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2021-07-01mm/page_alloc: move prototype for find_suitable_fallbackMel Gorman
make W=1 generates the following warning in mmap_lock.c for allnoconfig mm/page_alloc.c:2670:5: warning: no previous prototype for `find_suitable_fallback' [-Wmissing-prototypes] int find_suitable_fallback(struct free_area *area, unsigned int order, ^~~~~~~~~~~~~~~~~~~~~~ find_suitable_fallback is only shared outside of page_alloc.c for CONFIG_COMPACTION but to suppress the warning, move the protype outside of CONFIG_COMPACTION. It is not worth the effort at this time to find a clever way of allowing compaction.c to share the code or avoid the use entirely as the function is called on relatively slow paths. Link: https://lkml.kernel.org/r/20210520084809.8576-14-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Yang Shi <shy828301@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dan Streetman <ddstreet@ieee.org> Cc: David Hildenbrand <david@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01mm/mmap_lock: remove dead code for !CONFIG_TRACING configurationsMel Gorman
make W=1 generates the following warning in mmap_lock.c for allnoconfig mm/mmap_lock.c:213:6: warning: no previous prototype for `__mmap_lock_do_trace_start_locking' [-Wmissing-prototypes] void __mmap_lock_do_trace_start_locking(struct mm_struct *mm, bool write) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ mm/mmap_lock.c:219:6: warning: no previous prototype for `__mmap_lock_do_trace_acquire_returned' [-Wmissing-prototypes] void __mmap_lock_do_trace_acquire_returned(struct mm_struct *mm, bool write, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ mm/mmap_lock.c:226:6: warning: no previous prototype for `__mmap_lock_do_trace_released' [-Wmissing-prototypes] void __mmap_lock_do_trace_released(struct mm_struct *mm, bool write) On !CONFIG_TRACING configurations, the code is dead so put it behind an #ifdef. [cuibixuan@huawei.com: fix warning when CONFIG_TRACING is not defined] Link: https://lkml.kernel.org/r/20210531033426.74031-1-cuibixuan@huawei.com Link: https://lkml.kernel.org/r/20210520084809.8576-13-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Bixuan Cui <cuibixuan@huawei.com> Reviewed-by: Yang Shi <shy828301@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dan Streetman <ddstreet@ieee.org> Cc: David Hildenbrand <david@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01mm/z3fold: add kerneldoc fields for z3fold_poolMel Gorman
make W=1 generates the following warning for z3fold_pool mm/z3fold.c:171: warning: Function parameter or member 'zpool' not described in 'z3fold_pool' mm/z3fold.c:171: warning: Function parameter or member 'zpool_ops' not described in 'z3fold_pool' Commit 9a001fc19ccc ("z3fold: the 3-fold allocator for compressed pages") simply did not document the fields at the time. Add rudimentary documentation. Link: https://lkml.kernel.org/r/20210520084809.8576-11-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Yang Shi <shy828301@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dan Streetman <ddstreet@ieee.org> Cc: David Hildenbrand <david@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01mm/zbud: add kerneldoc fields for zbud_poolMel Gorman
make W=1 generates the following warning for zbud_pool mm/zbud.c:105: warning: Function parameter or member 'zpool' not described in 'zbud_pool' mm/zbud.c:105: warning: Function parameter or member 'zpool_ops' not described in 'zbud_pool' Commit 479305fd7172 ("zpool: remove zpool_evict()") removed the zpool_evict helper and added the associated zpool and operations structure in struct zbud_pool but did not add documentation for the fields. Add rudimentary documentation. Link: https://lkml.kernel.org/r/20210520084809.8576-10-mgorman@techsingularity.net Fixes: 479305fd7172 ("zpool: remove zpool_evict()") Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Yang Shi <shy828301@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dan Streetman <ddstreet@ieee.org> Cc: David Hildenbrand <david@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01mm/memory_hotplug: fix kerneldoc comment for __remove_memoryMel Gorman
make W=1 generates the following warning for __remove_memory mm/memory_hotplug.c:2044: warning: expecting prototype for remove_memory(). Prototype was for __remove_memory() instead Commit eca499ab3749 ("mm/hotplug: make remove_memory() interface usable") introduced the kerneldoc comment and function but the kerneldoc name and function name did not match. Link: https://lkml.kernel.org/r/20210520084809.8576-9-mgorman@techsingularity.net Fixes: eca499ab3749 ("mm/hotplug: make remove_memory() interface usable") Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Yang Shi <shy828301@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01mm/memory_hotplug: fix kerneldoc comment for __try_online_nodeMel Gorman
make W=1 generates the following warning for try_online_node mm/memory_hotplug.c:1087: warning: expecting prototype for try_online_node(). Prototype was for __try_online_node() instead Commit b9ff036082cd ("mm/memory_hotplug.c: make add_memory_resource use __try_online_node") renamed the function but did not update the associated kerneldoc. The function is static and somewhat specialised in nature so it's not clear it warrants being a kerneldoc by moving the comment to try_online_node. Hence, leave the comment of the internal helper in place but leave it out of kerneldoc and correct the function name in the comment. Link: https://lkml.kernel.org/r/20210520084809.8576-8-mgorman@techsingularity.net Fixes: Commit b9ff036082cd ("mm/memory_hotplug.c: make add_memory_resource use __try_online_node") Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Yang Shi <shy828301@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01mm/memcontrol.c: fix kerneldoc comment for mem_cgroup_calculate_protectionMel Gorman
make W=1 generates the following warning for mem_cgroup_calculate_protection mm/memcontrol.c:6468: warning: expecting prototype for mem_cgroup_protected(). Prototype was for mem_cgroup_calculate_protection() instead Commit 45c7f7e1ef17 ("mm, memcg: decouple e{low,min} state mutations from protection checks") changed the function definition but not the associated kerneldoc comment. Link: https://lkml.kernel.org/r/20210520084809.8576-7-mgorman@techsingularity.net Fixes: 45c7f7e1ef17 ("mm, memcg: decouple e{low,min} state mutations from protection checks") Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Yang Shi <shy828301@gmail.com> Acked-by: Chris Down <chris@chrisdown.name> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dan Streetman <ddstreet@ieee.org> Cc: David Hildenbrand <david@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01mm/mapping_dirty_helpers: remove double Note in kerneldocMel Gorman
make W=1 generates the following warning for mm/mapping_dirty_helpers.c mm/mapping_dirty_helpers.c:325: warning: duplicate section name 'Note' The helper function is very specific to one driver -- vmwgfx. While the two notes are separate, all of it needs to be taken into account when using the helper so make it one note. Link: https://lkml.kernel.org/r/20210520084809.8576-5-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Yang Shi <shy828301@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dan Streetman <ddstreet@ieee.org> Cc: David Hildenbrand <david@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01mm/page_alloc: make should_fail_alloc_page() staticMel Gorman
make W=1 generates the following warning for mm/page_alloc.c mm/page_alloc.c:3651:15: warning: no previous prototype for `should_fail_alloc_page' [-Wmissing-prototypes] noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order) ^~~~~~~~~~~~~~~~~~~~~~ This function is deliberately split out for BPF to allow errors to be injected. The function is not used anywhere else so it is local to the file. Make it static which should still allow error injection to be used similar to how block/blk-core.c:should_fail_bio() works. Link: https://lkml.kernel.org/r/20210520084809.8576-4-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Yang Shi <shy828301@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dan Streetman <ddstreet@ieee.org> Cc: David Hildenbrand <david@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01mm/vmalloc: include header for prototype of set_iounmap_nonlazyMel Gorman
make W=1 generates the following warning for mm/vmalloc.c mm/vmalloc.c:1599:6: warning: no previous prototype for `set_iounmap_nonlazy' [-Wmissing-prototypes] void set_iounmap_nonlazy(void) ^~~~~~~~~~~~~~~~~~~ This is an arch-generic function only used by x86. On other arches, it's dead code. Include the header with the definition and make it x86-64 specific. Link: https://lkml.kernel.org/r/20210520084809.8576-3-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Yang Shi <shy828301@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Dan Streetman <ddstreet@ieee.org> Cc: David Hildenbrand <david@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01mm/vmscan: remove kerneldoc-like comment from isolate_lru_pagesMel Gorman
Patch series "Clean W=1 build warnings for mm/". This is a janitorial only. During development of a tool to catch build warnings early to avoid tripping the Intel lkp-robot, I noticed that mm/ is not clean for W=1. This is generally harmless but there is no harm in cleaning it up. It disrupts git blame a little but on relatively obvious lines that are unlikely to be git blame targets. This patch (of 13): make W=1 generates the following warning for vmscan.c mm/vmscan.c:1814: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst It is not a kerneldoc comment and isolate_lru_pages() is a static function. While the detailed comment is nice, it does not need to be exposed via kernel-doc. Link: https://lkml.kernel.org/r/20210520084809.8576-1-mgorman@techsingularity.net Link: https://lkml.kernel.org/r/20210520084809.8576-2-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Yang Shi <shy828301@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Dan Streetman <ddstreet@ieee.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01mm: fix spelling mistakesZhen Lei
Fix some spelling mistakes in comments: each having differents usage ==> each has a different usage statments ==> statements adresses ==> addresses aggresive ==> aggressive datas ==> data posion ==> poison higer ==> higher precisly ==> precisely wont ==> won't We moves tha ==> We move the endianess ==> endianness Link: https://lkml.kernel.org/r/20210519065853.7723-2-thunder.leizhen@huawei.com Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Reviewed-by: Souptick Joarder <jrdr.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01mm: fix typos and grammar error in commentsHyeonggon Yoo
We moves tha -> We move that in mm/swap.c statments -> statements in include/linux/mm.h Link: https://lkml.kernel.org/r/20210509063444.GA24745@hyeyoo Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01mm/zsmalloc.c: improve readability for async_free_zspage()Miaohe Lin
The class is extracted from pool->size_class[class_idx] again before calling __free_zspage(). It looks like class will change after we fetch the class lock. But this is misleading as class will stay unchanged. Link: https://lkml.kernel.org/r/20210624123930.1769093-4-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01mm/zsmalloc.c: remove confusing code in obj_free()Miaohe Lin
Patch series "Cleanup for zsmalloc". This series contains cleanups to remove confusing code in obj_free(), combine two atomic ops and improve readability for async_free_zspage(). More details can be found in the respective changelogs. This patch (of 2): OBJ_ALLOCATED_TAG is only set for handle to indicate allocated object. It's irrelevant with obj. So remove this misleading code to improve readability. Link: https://lkml.kernel.org/r/20210624123930.1769093-1-linmiaohe@huawei.com Link: https://lkml.kernel.org/r/20210624123930.1769093-2-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm/zswap.c: fix two bugs in zswap_writeback_entry()Miaohe Lin
In the ZSWAP_SWAPCACHE_FAIL and ZSWAP_SWAPCACHE_EXIST case, we forgot to call zpool_unmap_handle() when zpool can't sleep. And we might sleep in zswap_get_swap_cache_page() while zpool can't sleep. To fix all of these, zpool_unmap_handle() should be done before zswap_get_swap_cache_page() when zpool can't sleep. Link: https://lkml.kernel.org/r/20210522092242.3233191-4-linmiaohe@huawei.com Fixes: fc6697a89f56 ("mm/zswap: add the flag can_sleep_mapped") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Seth Jennings <sjenning@redhat.com> Cc: Tian Tao <tiantao6@hisilicon.com> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm/zswap.c: avoid unnecessary copy-in at map timeMiaohe Lin
The buf mapped via zpool_map_handle() is only used to store compressed page buffer and there is no information to extract from it. So we could use ZPOOL_MM_WO instead to avoid unnecessary copy-in at map time. Link: https://lkml.kernel.org/r/20210522092242.3233191-3-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Seth Jennings <sjenning@redhat.com> Cc: Tian Tao <tiantao6@hisilicon.com> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm/zswap.c: remove unused function zswap_debugfs_exit()Miaohe Lin
Patch series "Cleanup and fixup for zswap". This series contains cleanups to remove unused function and avoid unnecessary copy-in at map time. Also this fixes two bugs in the function zswap_writeback_entry(). More details can be found in the respective changelogs. This patch (of 3): zswap_debugfs_exit() is unused, remove it. Link: https://lkml.kernel.org/r/20210522092242.3233191-1-linmiaohe@huawei.com Link: https://lkml.kernel.org/r/20210522092242.3233191-2-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Colin Ian King <colin.king@canonical.com> Cc: Tian Tao <tiantao6@hisilicon.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm,memory_hotplug: drop unneeded lockingOscar Salvador
Currently, memory-hotplug code takes zone's span_writelock and pgdat's resize_lock when resizing the node/zone's spanned pages via {move_pfn_range_to_zone(),remove_pfn_range_from_zone()} and when resizing node and zone's present pages via adjust_present_page_count(). These locks are also taken during the initialization of the system at boot time, where it protects parallel struct page initialization, but they should not really be needed in memory-hotplug where all operations are a) synchronized on device level and b) serialized by the mem_hotplug_lock lock. [akpm@linux-foundation.org: remove now-unused locals] Link: https://lkml.kernel.org/r/20210531093958.15021-1-osalvador@suse.de Signed-off-by: Oscar Salvador <osalvador@suse.de> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm/memory_hotplug: rate limit page migration warningsLiam Mark
When offlining memory the system can attempt to migrate a lot of pages, if there are problems with migration this can flood the logs. Printing all the data hogs the CPU and cause some RT threads to run for a long time, which may have some bad consequences. Rate limit the page migration warnings in order to avoid this. Link: https://lkml.kernel.org/r/20210505140542.24935-1-georgi.djakov@linaro.org Signed-off-by: Liam Mark <lmark@codeaurora.org> Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org> Cc: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm/madvise: introduce MADV_POPULATE_(READ|WRITE) to prefault page tablesDavid Hildenbrand
I. Background: Sparse Memory Mappings When we manage sparse memory mappings dynamically in user space - also sometimes involving MAP_NORESERVE - we want to dynamically populate/ discard memory inside such a sparse memory region. Example users are hypervisors (especially implementing memory ballooning or similar technologies like virtio-mem) and memory allocators. In addition, we want to fail in a nice way (instead of generating SIGBUS) if populating does not succeed because we are out of backend memory (which can happen easily with file-based mappings, especially tmpfs and hugetlbfs). While MADV_DONTNEED, MADV_REMOVE and FALLOC_FL_PUNCH_HOLE allow for reliably discarding memory for most mapping types, there is no generic approach to populate page tables and preallocate memory. Although mmap() supports MAP_POPULATE, it is not applicable to the concept of sparse memory mappings, where we want to populate/discard dynamically and avoid expensive/problematic remappings. In addition, we never actually report errors during the final populate phase - it is best-effort only. fallocate() can be used to preallocate file-based memory and fail in a safe way. However, it cannot really be used for any private mappings on anonymous files via memfd due to COW semantics. In addition, fallocate() does not actually populate page tables, so we still always get pagefaults on first access - which is sometimes undesired (i.e., real-time workloads) and requires real prefaulting of page tables, not just a preallocation of backend storage. There might be interesting use cases for sparse memory regions along with mlockall(MCL_ONFAULT) which fallocate() cannot satisfy as it does not prefault page tables. II. On preallcoation/prefaulting from user space Because we don't have a proper interface, what applications (like QEMU and databases) end up doing is touching (i.e., reading+writing one byte to not overwrite existing data) all individual pages. However, that approach 1) Can result in wear on storage backing, because we end up reading/writing each page; this is especially a problem for dax/pmem. 2) Can result in mmap_sem contention when prefaulting via multiple threads. 3) Requires expensive signal handling, especially to catch SIGBUS in case of hugetlbfs/shmem/file-backed memory. For example, this is problematic in hypervisors like QEMU where SIGBUS handlers might already be used by other subsystems concurrently to e.g, handle hardware errors. "Simply" doing preallocation concurrently from other thread is not that easy. III. On MADV_WILLNEED Extending MADV_WILLNEED is not an option because 1. It would change the semantics: "Expect access in the near future." and "might be a good idea to read some pages" vs. "Definitely populate/ preallocate all memory and definitely fail on errors.". 2. Existing users (like virtio-balloon in QEMU when deflating the balloon) don't want populate/prealloc semantics. They treat this rather as a hint to give a little performance boost without too much overhead - and don't expect that a lot of memory might get consumed or a lot of time might be spent. IV. MADV_POPULATE_READ and MADV_POPULATE_WRITE Let's introduce MADV_POPULATE_READ and MADV_POPULATE_WRITE, inspired by MAP_POPULATE, with the following semantics: 1. MADV_POPULATE_READ can be used to prefault page tables just like manually reading each individual page. This will not break any COW mappings. The shared zero page might get mapped and no backend storage might get preallocated -- allocation might be deferred to write-fault time. Especially shared file mappings require an explicit fallocate() upfront to actually preallocate backend memory (blocks in the file system) in case the file might have holes. 2. If MADV_POPULATE_READ succeeds, all page tables have been populated (prefaulted) readable once. 3. MADV_POPULATE_WRITE can be used to preallocate backend memory and prefault page tables just like manually writing (or reading+writing) each individual page. This will break any COW mappings -- e.g., the shared zeropage is never populated. 4. If MADV_POPULATE_WRITE succeeds, all page tables have been populated (prefaulted) writable once. 5. MADV_POPULATE_READ and MADV_POPULATE_WRITE cannot be applied to special mappings marked with VM_PFNMAP and VM_IO. Also, proper access permissions (e.g., PROT_READ, PROT_WRITE) are required. If any such mapping is encountered, madvise() fails with -EINVAL. 6. If MADV_POPULATE_READ or MADV_POPULATE_WRITE fails, some page tables might have been populated. 7. MADV_POPULATE_READ and MADV_POPULATE_WRITE will return -EHWPOISON when encountering a HW poisoned page in the range. 8. Similar to MAP_POPULATE, MADV_POPULATE_READ and MADV_POPULATE_WRITE cannot protect from the OOM (Out Of Memory) handler killing the process. While the use case for MADV_POPULATE_WRITE is fairly obvious (i.e., preallocate memory and prefault page tables for VMs), one issue is that whenever we prefault pages writable, the pages have to be marked dirty, because the CPU could dirty them any time. while not a real problem for hugetlbfs or dax/pmem, it can be a problem for shared file mappings: each page will be marked dirty and has to be written back later when evicting. MADV_POPULATE_READ allows for optimizing this scenario: Pre-read a whole mapping from backend storage without marking it dirty, such that eviction won't have to write it back. As discussed above, shared file mappings might require an explciit fallocate() upfront to achieve preallcoation+prepopulation. Although sparse memory mappings are the primary use case, this will also be useful for other preallocate/prefault use cases where MAP_POPULATE is not desired or the semantics of MAP_POPULATE are not sufficient: as one example, QEMU users can trigger preallocation/prefaulting of guest RAM after the mapping was created -- and don't want errors to be silently suppressed. Looking at the history, MADV_POPULATE was already proposed in 2013 [1], however, the main motivation back than was performance improvements -- which should also still be the case. V. Single-threaded performance comparison I did a short experiment, prefaulting page tables on completely *empty mappings/files* and repeated the experiment 10 times. The results correspond to the shortest execution time. In general, the performance benefit for huge pages is negligible with small mappings. V.1: Private mappings POPULATE_READ and POPULATE_WRITE is fastest. Note that Reading/POPULATE_READ will populate the shared zeropage where applicable -- which result in short population times. The fastest way to allocate backend storage (here: swap or huge pages) and prefault page tables is POPULATE_WRITE. V.2: Shared mappings fallocate() is fastest, however, doesn't prefault page tables. POPULATE_WRITE is faster than simple writes and read/writes. POPULATE_READ is faster than simple reads. Without a fd, the fastest way to allocate backend storage and prefault page tables is POPULATE_WRITE. With an fd, the fastest way is usually FALLOCATE+POPULATE_READ or FALLOCATE+POPULATE_WRITE respectively; one exception are actual files: FALLOCATE+Read is slightly faster than FALLOCATE+POPULATE_READ. The fastest way to allocate backend storage prefault page tables is FALLOCATE+POPULATE_WRITE -- except when dealing with actual files; then, FALLOCATE+POPULATE_READ is fastest and won't directly mark all pages as dirty. v.3: Detailed results ================================================== 2 MiB MAP_PRIVATE: ************************************************** Anon 4 KiB : Read : 0.119 ms Anon 4 KiB : Write : 0.222 ms Anon 4 KiB : Read/Write : 0.380 ms Anon 4 KiB : POPULATE_READ : 0.060 ms Anon 4 KiB : POPULATE_WRITE : 0.158 ms Memfd 4 KiB : Read : 0.034 ms Memfd 4 KiB : Write : 0.310 ms Memfd 4 KiB : Read/Write : 0.362 ms Memfd 4 KiB : POPULATE_READ : 0.039 ms Memfd 4 KiB : POPULATE_WRITE : 0.229 ms Memfd 2 MiB : Read : 0.030 ms Memfd 2 MiB : Write : 0.030 ms Memfd 2 MiB : Read/Write : 0.030 ms Memfd 2 MiB : POPULATE_READ : 0.030 ms Memfd 2 MiB : POPULATE_WRITE : 0.030 ms tmpfs : Read : 0.033 ms tmpfs : Write : 0.313 ms tmpfs : Read/Write : 0.406 ms tmpfs : POPULATE_READ : 0.039 ms tmpfs : POPULATE_WRITE : 0.285 ms file : Read : 0.033 ms file : Write : 0.351 ms file : Read/Write : 0.408 ms file : POPULATE_READ : 0.039 ms file : POPULATE_WRITE : 0.290 ms hugetlbfs : Read : 0.030 ms hugetlbfs : Write : 0.030 ms hugetlbfs : Read/Write : 0.030 ms hugetlbfs : POPULATE_READ : 0.030 ms hugetlbfs : POPULATE_WRITE : 0.030 ms ************************************************** 4096 MiB MAP_PRIVATE: ************************************************** Anon 4 KiB : Read : 237.940 ms Anon 4 KiB : Write : 708.409 ms Anon 4 KiB : Read/Write : 1054.041 ms Anon 4 KiB : POPULATE_READ : 124.310 ms Anon 4 KiB : POPULATE_WRITE : 572.582 ms Memfd 4 KiB : Read : 136.928 ms Memfd 4 KiB : Write : 963.898 ms Memfd 4 KiB : Read/Write : 1106.561 ms Memfd 4 KiB : POPULATE_READ : 78.450 ms Memfd 4 KiB : POPULATE_WRITE : 805.881 ms Memfd 2 MiB : Read : 357.116 ms Memfd 2 MiB : Write : 357.210 ms Memfd 2 MiB : Read/Write : 357.606 ms Memfd 2 MiB : POPULATE_READ : 356.094 ms Memfd 2 MiB : POPULATE_WRITE : 356.937 ms tmpfs : Read : 137.536 ms tmpfs : Write : 954.362 ms tmpfs : Read/Write : 1105.954 ms tmpfs : POPULATE_READ : 80.289 ms tmpfs : POPULATE_WRITE : 822.826 ms file : Read : 137.874 ms file : Write : 987.025 ms file : Read/Write : 1107.439 ms file : POPULATE_READ : 80.413 ms file : POPULATE_WRITE : 857.622 ms hugetlbfs : Read : 355.607 ms hugetlbfs : Write : 355.729 ms hugetlbfs : Read/Write : 356.127 ms hugetlbfs : POPULATE_READ : 354.585 ms hugetlbfs : POPULATE_WRITE : 355.138 ms ************************************************** 2 MiB MAP_SHARED: ************************************************** Anon 4 KiB : Read : 0.394 ms Anon 4 KiB : Write : 0.348 ms Anon 4 KiB : Read/Write : 0.400 ms Anon 4 KiB : POPULATE_READ : 0.326 ms Anon 4 KiB : POPULATE_WRITE : 0.273 ms Anon 2 MiB : Read : 0.030 ms Anon 2 MiB : Write : 0.030 ms Anon 2 MiB : Read/Write : 0.030 ms Anon 2 MiB : POPULATE_READ : 0.030 ms Anon 2 MiB : POPULATE_WRITE : 0.030 ms Memfd 4 KiB : Read : 0.412 ms Memfd 4 KiB : Write : 0.372 ms Memfd 4 KiB : Read/Write : 0.419 ms Memfd 4 KiB : POPULATE_READ : 0.343 ms Memfd 4 KiB : POPULATE_WRITE : 0.288 ms Memfd 4 KiB : FALLOCATE : 0.137 ms Memfd 4 KiB : FALLOCATE+Read : 0.446 ms Memfd 4 KiB : FALLOCATE+Write : 0.330 ms Memfd 4 KiB : FALLOCATE+Read/Write : 0.454 ms Memfd 4 KiB : FALLOCATE+POPULATE_READ : 0.379 ms Memfd 4 KiB : FALLOCATE+POPULATE_WRITE : 0.268 ms Memfd 2 MiB : Read : 0.030 ms Memfd 2 MiB : Write : 0.030 ms Memfd 2 MiB : Read/Write : 0.030 ms Memfd 2 MiB : POPULATE_READ : 0.030 ms Memfd 2 MiB : POPULATE_WRITE : 0.030 ms Memfd 2 MiB : FALLOCATE : 0.030 ms Memfd 2 MiB : FALLOCATE+Read : 0.031 ms Memfd 2 MiB : FALLOCATE+Write : 0.031 ms Memfd 2 MiB : FALLOCATE+Read/Write : 0.031 ms Memfd 2 MiB : FALLOCATE+POPULATE_READ : 0.030 ms Memfd 2 MiB : FALLOCATE+POPULATE_WRITE : 0.030 ms tmpfs : Read : 0.416 ms tmpfs : Write : 0.369 ms tmpfs : Read/Write : 0.425 ms tmpfs : POPULATE_READ : 0.346 ms tmpfs : POPULATE_WRITE : 0.295 ms tmpfs : FALLOCATE : 0.139 ms tmpfs : FALLOCATE+Read : 0.447 ms tmpfs : FALLOCATE+Write : 0.333 ms tmpfs : FALLOCATE+Read/Write : 0.454 ms tmpfs : FALLOCATE+POPULATE_READ : 0.380 ms tmpfs : FALLOCATE+POPULATE_WRITE : 0.272 ms file : Read : 0.191 ms file : Write : 0.511 ms file : Read/Write : 0.524 ms file : POPULATE_READ : 0.196 ms file : POPULATE_WRITE : 0.434 ms file : FALLOCATE : 0.004 ms file : FALLOCATE+Read : 0.197 ms file : FALLOCATE+Write : 0.554 ms file : FALLOCATE+Read/Write : 0.480 ms file : FALLOCATE+POPULATE_READ : 0.201 ms file : FALLOCATE+POPULATE_WRITE : 0.381 ms hugetlbfs : Read : 0.030 ms hugetlbfs : Write : 0.030 ms hugetlbfs : Read/Write : 0.030 ms hugetlbfs : POPULATE_READ : 0.030 ms hugetlbfs : POPULATE_WRITE : 0.030 ms hugetlbfs : FALLOCATE : 0.030 ms hugetlbfs : FALLOCATE+Read : 0.031 ms hugetlbfs : FALLOCATE+Write : 0.031 ms hugetlbfs : FALLOCATE+Read/Write : 0.030 ms hugetlbfs : FALLOCATE+POPULATE_READ : 0.030 ms hugetlbfs : FALLOCATE+POPULATE_WRITE : 0.030 ms ************************************************** 4096 MiB MAP_SHARED: ************************************************** Anon 4 KiB : Read : 1053.090 ms Anon 4 KiB : Write : 913.642 ms Anon 4 KiB : Read/Write : 1060.350 ms Anon 4 KiB : POPULATE_READ : 893.691 ms Anon 4 KiB : POPULATE_WRITE : 782.885 ms Anon 2 MiB : Read : 358.553 ms Anon 2 MiB : Write : 358.419 ms Anon 2 MiB : Read/Write : 357.992 ms Anon 2 MiB : POPULATE_READ : 357.533 ms Anon 2 MiB : POPULATE_WRITE : 357.808 ms Memfd 4 KiB : Read : 1078.144 ms Memfd 4 KiB : Write : 942.036 ms Memfd 4 KiB : Read/Write : 1100.391 ms Memfd 4 KiB : POPULATE_READ : 925.829 ms Memfd 4 KiB : POPULATE_WRITE : 804.394 ms Memfd 4 KiB : FALLOCATE : 304.632 ms Memfd 4 KiB : FALLOCATE+Read : 1163.359 ms Memfd 4 KiB : FALLOCATE+Write : 933.186 ms Memfd 4 KiB : FALLOCATE+Read/Write : 1187.304 ms Memfd 4 KiB : FALLOCATE+POPULATE_READ : 1013.660 ms Memfd 4 KiB : FALLOCATE+POPULATE_WRITE : 794.560 ms Memfd 2 MiB : Read : 358.131 ms Memfd 2 MiB : Write : 358.099 ms Memfd 2 MiB : Read/Write : 358.250 ms Memfd 2 MiB : POPULATE_READ : 357.563 ms Memfd 2 MiB : POPULATE_WRITE : 357.334 ms Memfd 2 MiB : FALLOCATE : 356.735 ms Memfd 2 MiB : FALLOCATE+Read : 358.152 ms Memfd 2 MiB : FALLOCATE+Write : 358.331 ms Memfd 2 MiB : FALLOCATE+Read/Write : 358.018 ms Memfd 2 MiB : FALLOCATE+POPULATE_READ : 357.286 ms Memfd 2 MiB : FALLOCATE+POPULATE_WRITE : 357.523 ms tmpfs : Read : 1087.265 ms tmpfs : Write : 950.840 ms tmpfs : Read/Write : 1107.567 ms tmpfs : POPULATE_READ : 922.605 ms tmpfs : POPULATE_WRITE : 810.094 ms tmpfs : FALLOCATE : 306.320 ms tmpfs : FALLOCATE+Read : 1169.796 ms tmpfs : FALLOCATE+Write : 933.730 ms tmpfs : FALLOCATE+Read/Write : 1191.610 ms tmpfs : FALLOCATE+POPULATE_READ : 1020.474 ms tmpfs : FALLOCATE+POPULATE_WRITE : 798.945 ms file : Read : 654.101 ms file : Write : 1259.142 ms file : Read/Write : 1289.509 ms file : POPULATE_READ : 661.642 ms file : POPULATE_WRITE : 1106.816 ms file : FALLOCATE : 1.864 ms file : FALLOCATE+Read : 656.328 ms file : FALLOCATE+Write : 1153.300 ms file : FALLOCATE+Read/Write : 1180.613 ms file : FALLOCATE+POPULATE_READ : 668.347 ms file : FALLOCATE+POPULATE_WRITE : 996.143 ms hugetlbfs : Read : 357.245 ms hugetlbfs : Write : 357.413 ms hugetlbfs : Read/Write : 357.120 ms hugetlbfs : POPULATE_READ : 356.321 ms hugetlbfs : POPULATE_WRITE : 356.693 ms hugetlbfs : FALLOCATE : 355.927 ms hugetlbfs : FALLOCATE+Read : 357.074 ms hugetlbfs : FALLOCATE+Write : 357.120 ms hugetlbfs : FALLOCATE+Read/Write : 356.983 ms hugetlbfs : FALLOCATE+POPULATE_READ : 356.413 ms hugetlbfs : FALLOCATE+POPULATE_WRITE : 356.266 ms ************************************************** [1] https://lkml.org/lkml/2013/6/27/698 [akpm@linux-foundation.org: coding style fixes] Link: https://lkml.kernel.org/r/20210419135443.12822-3-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@surriel.com> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Helge Deller <deller@gmx.de> Cc: Chris Zankel <chris@zankel.net> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Peter Xu <peterx@redhat.com> Cc: Rolf Eike Beer <eike-kernel@sf-tec.de> Cc: Ram Pai <linuxram@us.ibm.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm: make variable names for populate_vma_page_range() consistentDavid Hildenbrand
Patch series "mm/madvise: introduce MADV_POPULATE_(READ|WRITE) to prefault page tables", v2. Excessive details on MADV_POPULATE_(READ|WRITE) can be found in patch #2. This patch (of 5): Let's make the variable names in the function declaration match the variable names used in the definition. Link: https://lkml.kernel.org/r/20210419135443.12822-1-david@redhat.com Link: https://lkml.kernel.org/r/20210419135443.12822-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Peter Xu <peterx@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Chris Zankel <chris@zankel.net> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Helge Deller <deller@gmx.de> Cc: Hugh Dickins <hughd@google.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Jann Horn <jannh@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Ram Pai <linuxram@us.ibm.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Rik van Riel <riel@surriel.com> Cc: Rolf Eike Beer <eike-kernel@sf-tec.de> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm: generalize ZONE_[DMA|DMA32]Kefeng Wang
ZONE_[DMA|DMA32] configs have duplicate definitions on platforms that subscribe to them. Instead, just make them generic options which can be selected on applicable platforms. Also only x86/arm64 architectures could enable both ZONE_DMA and ZONE_DMA32 if EXPERT, add ARCH_HAS_ZONE_DMA_SET to make dma zone configurable and visible on the two architectures. Link: https://lkml.kernel.org/r/20210528074557.17768-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64] Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k] Acked-by: Mike Rapoport <rppt@linux.ibm.com> Acked-by: Palmer Dabbelt <palmerdabbelt@google.com> [RISC-V] Acked-by: Michal Simek <michal.simek@xilinx.com> [microblaze] Acked-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc] Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: "David S. Miller" <davem@davemloft.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Richard Henderson <rth@twiddle.net> Cc: Russell King <linux@armlinux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm/nommu: unexport do_munmap()Liam Howlett
do_munmap() does not take the mmap_write_lock(). vm_munmap() should be used instead. Link: https://lkml.kernel.org/r/20210604194002.648037-1-Liam.Howlett@Oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30nommu: remove __GFP_HIGHMEM in vmalloc/vzallocChen Li
mm/nommu.c: void *__vmalloc(unsigned long size, gfp_t gfp_mask) { /* * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc() * returns only a logical address. */ return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM); } nommu's __vmalloc just uses kmalloc internally and elimitates __GFP_HIGHMEM, so it makes no sense to add __GFP_HIGHMEM for nommu's vmalloc/vzalloc. [akpm@linux-foundation.org: coding style fixes] Link: https://lkml.kernel.org/r/875z00rnp8.wl-chenli@uniontech.com Signed-off-by: Chen Li <chenli@uniontech.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm/thp: fix strncpy warningMatthew Wilcox (Oracle)
Using MAX_INPUT_BUF_SZ as the maximum length of the string makes fortify complain as it thinks the string might be longer than the buffer, and if it is, we will end up with a "string" that is missing a NUL terminator. It's trivial to show that 'tok' points to a NUL-terminated string which is less than MAX_INPUT_BUF_SZ in length, so we may as well just use strcpy() and avoid the warning. Link: https://lkml.kernel.org/r/20210615200242.1716568-4-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm: hwpoison_user_mappings() try_to_unmap() with TTU_SYNCHugh Dickins
TTU_SYNC prevents an unlikely race, when try_to_unmap() returns shortly before the page is accounted as unmapped. It is unlikely to coincide with hwpoisoning, but now that we have the flag, hwpoison_user_mappings() would do well to use it. Link: https://lkml.kernel.org/r/329c28ed-95df-9a2c-8893-b444d8a6d340@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Jan Kara <jack@suse.cz> Cc: Jue Wang <juew@google.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Wang Yugui <wangyugui@e16-tech.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm/thp: remap_page() is only needed on anonymous THPHugh Dickins
THP splitting's unmap_page() only sets TTU_SPLIT_FREEZE when PageAnon, and migration entries are only inserted when TTU_MIGRATION (unused here) or TTU_SPLIT_FREEZE is set: so it's just a waste of time for remap_page() to search for migration entries to remove when !PageAnon. Link: https://lkml.kernel.org/r/f987bc44-f28e-688d-2424-b4722153ed8@google.com Fixes: baa355fd3314 ("thp: file pages support for split_huge_page()") Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Yang Shi <shy828301@gmail.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Jan Kara <jack@suse.cz> Cc: Jue Wang <juew@google.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Wang Yugui <wangyugui@e16-tech.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm: rmap: make try_to_unmap() void functionYang Shi
Currently try_to_unmap() return bool value by checking page_mapcount(), however this may return false positive since page_mapcount() doesn't check all subpages of compound page. The total_mapcount() could be used instead, but its cost is higher since it traverses all subpages. Actually the most callers of try_to_unmap() don't care about the return value at all. So just need check if page is still mapped by page_mapped() when necessary. And page_mapped() does bail out early when it finds mapped subpage. Link: https://lkml.kernel.org/r/bb27e3fe-6036-b637-5086-272befbfe3da@google.com Suggested-by: Hugh Dickins <hughd@google.com> Signed-off-by: Yang Shi <shy828301@gmail.com> Acked-by: Minchan Kim <minchan@kernel.org> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Jan Kara <jack@suse.cz> Cc: Jue Wang <juew@google.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Wang Yugui <wangyugui@e16-tech.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm: thp: skip make PMD PROT_NONE if THP migration is not supportedYang Shi
A quick grep shows x86_64, PowerPC (book3s), ARM64 and S390 support both NUMA balancing and THP. But S390 doesn't support THP migration so NUMA balancing actually can't migrate any misplaced pages. Skip make PMD PROT_NONE for such case otherwise CPU cycles may be wasted by pointless NUMA hinting faults on S390. Link: https://lkml.kernel.org/r/20210518200801.7413-8-shy828301@gmail.com Signed-off-by: Yang Shi <shy828301@gmail.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm: migrate: check mapcount for THP instead of refcountYang Shi
The generic migration path will check refcount, so no need check refcount here. But the old code actually prevents from migrating shared THP (mapped by multiple processes), so bail out early if mapcount is > 1 to keep the behavior. Link: https://lkml.kernel.org/r/20210518200801.7413-7-shy828301@gmail.com Signed-off-by: Yang Shi <shy828301@gmail.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm: migrate: don't split THP for misplaced NUMA pageYang Shi
The old behavior didn't split THP if migration is failed due to lack of memory on the target node. But the THP migration does split THP, so keep the old behavior for misplaced NUMA page migration. Link: https://lkml.kernel.org/r/20210518200801.7413-6-shy828301@gmail.com Signed-off-by: Yang Shi <shy828301@gmail.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm: migrate: account THP NUMA migration counters correctlyYang Shi
Now both base page and THP NUMA migration is done via migrate_misplaced_page(), keep the counters correctly for THP. Link: https://lkml.kernel.org/r/20210518200801.7413-5-shy828301@gmail.com Signed-off-by: Yang Shi <shy828301@gmail.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm: thp: refactor NUMA fault handlingYang Shi
When the THP NUMA fault support was added THP migration was not supported yet. So the ad hoc THP migration was implemented in NUMA fault handling. Since v4.14 THP migration has been supported so it doesn't make too much sense to still keep another THP migration implementation rather than using the generic migration code. This patch reworks the NUMA fault handling to use generic migration implementation to migrate misplaced page. There is no functional change. After the refactor the flow of NUMA fault handling looks just like its PTE counterpart: Acquire ptl Prepare for migration (elevate page refcount) Release ptl Isolate page from lru and elevate page refcount Migrate the misplaced THP If migration fails just restore the old normal PMD. In the old code anon_vma lock was needed to serialize THP migration against THP split, but since then the THP code has been reworked a lot, it seems anon_vma lock is not required anymore to avoid the race. The page refcount elevation when holding ptl should prevent from THP split. Use migrate_misplaced_page() for both base page and THP NUMA hinting fault and remove all the dead and duplicate code. [dan.carpenter@oracle.com: fix a double unlock bug] Link: https://lkml.kernel.org/r/YLX8uYN01JmfLnlK@mwanda Link: https://lkml.kernel.org/r/20210518200801.7413-4-shy828301@gmail.com Signed-off-by: Yang Shi <shy828301@gmail.com> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm: memory: make numa_migrate_prep() non-staticYang Shi
The numa_migrate_prep() will be used by huge NUMA fault as well in the following patch, make it non-static. Link: https://lkml.kernel.org/r/20210518200801.7413-3-shy828301@gmail.com Signed-off-by: Yang Shi <shy828301@gmail.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm: memory: add orig_pmd to struct vm_faultYang Shi
Pach series "mm: thp: use generic THP migration for NUMA hinting fault", v3. When the THP NUMA fault support was added THP migration was not supported yet. So the ad hoc THP migration was implemented in NUMA fault handling. Since v4.14 THP migration has been supported so it doesn't make too much sense to still keep another THP migration implementation rather than using the generic migration code. It is definitely a maintenance burden to keep two THP migration implementation for different code paths and it is more error prone. Using the generic THP migration implementation allows us remove the duplicate code and some hacks needed by the old ad hoc implementation. A quick grep shows x86_64, PowerPC (book3s), ARM64 ans S390 support both THP and NUMA balancing. The most of them support THP migration except for S390. Zi Yan tried to add THP migration support for S390 before but it was not accepted due to the design of S390 PMD. For the discussion, please see: https://lkml.org/lkml/2018/4/27/953. Per the discussion with Gerald Schaefer in v1 it is acceptible to skip huge PMD for S390 for now. I saw there were some hacks about gup from git history, but I didn't figure out if they have been removed or not since I just found FOLL_NUMA code in the current gup implementation and they seems useful. Patch #1 ~ #2 are preparation patches. Patch #3 is the real meat. Patch #4 ~ #6 keep consistent counters and behaviors with before. Patch #7 skips change huge PMD to prot_none if thp migration is not supported. Test ---- Did some tests to measure the latency of do_huge_pmd_numa_page. The test VM has 80 vcpus and 64G memory. The test would create 2 processes to consume 128G memory together which would incur memory pressure to cause THP splits. And it also creates 80 processes to hog cpu, and the memory consumer processes are bound to different nodes periodically in order to increase NUMA faults. The below test script is used: echo 3 > /proc/sys/vm/drop_caches # Run stress-ng for 24 hours ./stress-ng/stress-ng --vm 2 --vm-bytes 64G --timeout 24h & PID=$! ./stress-ng/stress-ng --cpu $NR_CPUS --timeout 24h & # Wait for vm stressors forked sleep 5 PID_1=`pgrep -P $PID | awk 'NR == 1'` PID_2=`pgrep -P $PID | awk 'NR == 2'` JOB1=`pgrep -P $PID_1` JOB2=`pgrep -P $PID_2` # Bind load jobs to different nodes periodically to force generate # cross node memory access while [ -d "/proc/$PID" ] do taskset -apc 8 $JOB1 taskset -apc 8 $JOB2 sleep 300 taskset -apc 58 $JOB1 taskset -apc 58 $JOB2 sleep 300 done With the above test the histogram of latency of do_huge_pmd_numa_page is as shown below. Since the number of do_huge_pmd_numa_page varies drastically for each run (should be due to scheduler), so I converted the raw number to percentage. patched base @us[stress-ng]: [0] 3.57% 0.16% [1] 55.68% 18.36% [2, 4) 10.46% 40.44% [4, 8) 7.26% 17.82% [8, 16) 21.12% 13.41% [16, 32) 1.06% 4.27% [32, 64) 0.56% 4.07% [64, 128) 0.16% 0.35% [128, 256) < 0.1% < 0.1% [256, 512) < 0.1% < 0.1% [512, 1K) < 0.1% < 0.1% [1K, 2K) < 0.1% < 0.1% [2K, 4K) < 0.1% < 0.1% [4K, 8K) < 0.1% < 0.1% [8K, 16K) < 0.1% < 0.1% [16K, 32K) < 0.1% < 0.1% [32K, 64K) < 0.1% < 0.1% Per the result, patched kernel is even slightly better than the base kernel. I think this is because the lock contention against THP split is less than base kernel due to the refactor. To exclude the affect from THP split, I also did test w/o memory pressure. No obvious regression is spotted. The below is the test result *w/o* memory pressure. patched base @us[stress-ng]: [0] 7.97% 18.4% [1] 69.63% 58.24% [2, 4) 4.18% 2.63% [4, 8) 0.22% 0.17% [8, 16) 1.03% 0.92% [16, 32) 0.14% < 0.1% [32, 64) < 0.1% < 0.1% [64, 128) < 0.1% < 0.1% [128, 256) < 0.1% < 0.1% [256, 512) 0.45% 1.19% [512, 1K) 15.45% 17.27% [1K, 2K) < 0.1% < 0.1% [2K, 4K) < 0.1% < 0.1% [4K, 8K) < 0.1% < 0.1% [8K, 16K) 0.86% 0.88% [16K, 32K) < 0.1% 0.15% [32K, 64K) < 0.1% < 0.1% [64K, 128K) < 0.1% < 0.1% [128K, 256K) < 0.1% < 0.1% The series also survived a series of tests that exercise NUMA balancing migrations by Mel. This patch (of 7): Add orig_pmd to struct vm_fault so the "orig_pmd" parameter used by huge page fault could be removed, just like its PTE counterpart does. Link: https://lkml.kernel.org/r/20210518200801.7413-1-shy828301@gmail.com Link: https://lkml.kernel.org/r/20210518200801.7413-2-shy828301@gmail.com Signed-off-by: Yang Shi <shy828301@gmail.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Hugh Dickins <hughd@google.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm, thp: relax the VM_DENYWRITE constraint on file-backed THPsCollin Fijalkovich
Transparent huge pages are supported for read-only non-shmem files, but are only used for vmas with VM_DENYWRITE. This condition ensures that file THPs are protected from writes while an application is running (ETXTBSY). Any existing file THPs are then dropped from the page cache when a file is opened for write in do_dentry_open(). Since sys_mmap ignores MAP_DENYWRITE, this constrains the use of file THPs to vmas produced by execve(). Systems that make heavy use of shared libraries (e.g. Android) are unable to apply VM_DENYWRITE through the dynamic linker, preventing them from benefiting from the resultant reduced contention on the TLB. This patch reduces the constraint on file THPs allowing use with any executable mapping from a file not opened for write (see inode_is_open_for_write()). It also introduces additional conditions to ensure that files opened for write will never be backed by file THPs. Restricting the use of THPs to executable mappings eliminates the risk that a read-only file later opened for write would encounter significant latencies due to page cache truncation. The ld linker flag '-z max-page-size=(hugepage size)' can be used to produce executables with the necessary layout. The dynamic linker must map these file's segments at a hugepage size aligned vma for the mapping to be backed with THPs. Comparison of the performance characteristics of 4KB and 2MB-backed libraries follows; the Android dex2oat tool was used to AOT compile an example application on a single ARM core. 4KB Pages: ========== count event_name # count / runtime 598,995,035,942 cpu-cycles # 1.800861 GHz 81,195,620,851 raw-stall-frontend # 244.112 M/sec 347,754,466,597 iTLB-loads # 1.046 G/sec 2,970,248,900 iTLB-load-misses # 0.854122% miss rate Total test time: 332.854998 seconds. 2MB Pages: ========== count event_name # count / runtime 592,872,663,047 cpu-cycles # 1.800358 GHz 76,485,624,143 raw-stall-frontend # 232.261 M/sec 350,478,413,710 iTLB-loads # 1.064 G/sec 803,233,322 iTLB-load-misses # 0.229182% miss rate Total test time: 329.826087 seconds A check of /proc/$(pidof dex2oat64)/smaps shows THPs in use: /apex/com.android.art/lib64/libart.so FilePmdMapped: 4096 kB /apex/com.android.art/lib64/libart-compiler.so FilePmdMapped: 2048 kB Link: https://lkml.kernel.org/r/20210406000930.3455850-1-cfijalkovich@google.com Signed-off-by: Collin Fijalkovich <cfijalkovich@google.com> Acked-by: Hugh Dickins <hughd@google.com> Reviewed-by: William Kucharski <william.kucharski@oracle.com> Acked-by: Song Liu <song@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Hridya Valsaraju <hridya@google.com> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Tim Murray <timmurray@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm: migrate: fix missing update page_private to hugetlb_page_subpoolMuchun Song
Since commit d6995da31122 ("hugetlb: use page.private for hugetlb specific page flags") converts page.private for hugetlb specific page flags. We should use hugetlb_page_subpool() to get the subpool pointer instead of page_private(). This 'could' prevent the migration of hugetlb pages. page_private(hpage) is now used for hugetlb page specific flags. At migration time, the only flag which could be set is HPageVmemmapOptimized. This flag will only be set if the new vmemmap reduction feature is enabled. In addition, !page_mapping() implies an anonymous mapping. So, this will prevent migration of hugetb pages in anonymous mappings if the vmemmap reduction feature is enabled. In addition, that if statement checked for the rare race condition of a page being migrated while in the process of being freed. Since that check is now wrong, we could leak hugetlb subpool usage counts. The commit forgot to update it in the page migration routine. So fix it. [songmuchun@bytedance.com: fix compiler error when !CONFIG_HUGETLB_PAGE reported by Randy] Link: https://lkml.kernel.org/r/20210521022747.35736-1-songmuchun@bytedance.com Link: https://lkml.kernel.org/r/20210520025949.1866-1-songmuchun@bytedance.com Fixes: d6995da31122 ("hugetlb: use page.private for hugetlb specific page flags") Signed-off-by: Muchun Song <songmuchun@bytedance.com> Reported-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Acked-by: Michal Hocko <mhocko@suse.com> Tested-by: Anshuman Khandual <anshuman.khandual@arm.com> [arm64] Cc: Oscar Salvador <osalvador@suse.de> Cc: David Hildenbrand <david@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Xiongchun Duan <duanxiongchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30memblock: update initialization of reserved pagesMike Rapoport
The struct pages representing a reserved memory region are initialized using reserve_bootmem_range() function. This function is called for each reserved region just before the memory is freed from memblock to the buddy page allocator. The struct pages for MEMBLOCK_NOMAP regions are kept with the default values set by the memory map initialization which makes it necessary to have a special treatment for such pages in pfn_valid() and pfn_valid_within(). Split out initialization of the reserved pages to a function with a meaningful name and treat the MEMBLOCK_NOMAP regions the same way as the reserved regions and mark struct pages for the NOMAP regions as PageReserved. Link: https://lkml.kernel.org/r/20210511100550.28178-3-rppt@kernel.org Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm/mempolicy: use unified 'nodes' for bind/interleave/prefer policiesBen Widawsky
Current structure 'mempolicy' uses a union to store the node info for bind/interleave/perfer policies. union { short preferred_node; /* preferred */ nodemask_t nodes; /* interleave/bind */ /* undefined for default */ } v; Since preferred node can also be represented by a nodemask_t with only ont bit set, unify these policies with using one nodemask_t 'nodes', which can remove a union, simplify the code and make it easier to support future's new policy's node info. Link: https://lore.kernel.org/r/20200630212517.308045-7-ben.widawsky@intel.com Link: https://lkml.kernel.org/r/1623399825-75651-1-git-send-email-feng.tang@intel.com Co-developed-by: Feng Tang <feng.tang@intel.com> Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Signed-off-by: Feng Tang <feng.tang@intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andi Kleen <ak@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm: mempolicy: don't have to split pmd for huge zero pageYang Shi
When trying to migrate pages to obey mempolicy, the huge zero page is split by inserting base zero pfn to all PTEs, then the page table walk fallback to PTE level and just skips zero page. Skipping zero page for mempolicy has been the behavior of kernel since v2.6.16 due to commit f4598c8b3678 ("[PATCH] migration: make sure there is no attempt to migrate reserved pages."). So it seems pointless to split huge zero page, it could be just skipped like base zero page. Set ACTION_CONTINUE to prevent the walk_page_range() split the pmd for this case. Link: https://lkml.kernel.org/r/20210609172146.3594-1-shy828301@gmail.com Link: https://lkml.kernel.org/r/20210604203513.240709-1-shy828301@gmail.com Signed-off-by: Yang Shi <shy828301@gmail.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm/mempolicy: unify the parameter sanity check for mbind and set_mempolicyFeng Tang
Currently the kernel_mbind() and kernel_set_mempolicy() do almost the same operation for parameter sanity check. Add a helper function to unify the code to reduce the redundancy, and make it easier for changing the sanity check code in future. [thanks to David Rientjes for suggesting using helper function instead of macro]. [feng.tang@intel.com: add comment] Link: https://lkml.kernel.org/r/1622560492-1294-4-git-send-email-feng.tang@intel.com Link: https://lkml.kernel.org/r/1622469956-82897-4-git-send-email-feng.tang@intel.com Signed-off-by: Feng Tang <feng.tang@intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: David Rientjes <rientjes@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Ben Widawsky <ben.widawsky@intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andi Kleen <ak@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm/mempolicy: don't handle MPOL_LOCAL like a fake MPOL_PREFERRED policyFeng Tang
MPOL_LOCAL policy has been setup as a real policy, but it is still handled like a faked POL_PREFERRED policy with one internal MPOL_F_LOCAL flag bit set, and there are many places having to judge the real 'prefer' or the 'local' policy, which are quite confusing. In current code, there are 4 cases that MPOL_LOCAL are used: 1. user specifies 'local' policy 2. user specifies 'prefer' policy, but with empty nodemask 3. system 'default' policy is used 4. 'prefer' policy + valid 'preferred' node with MPOL_F_STATIC_NODES flag set, and when it is 'rebind' to a nodemask which doesn't contains the 'preferred' node, it will perform as 'local' policy So make 'local' a real policy instead of a fake 'prefer' one, and kill MPOL_F_LOCAL bit, which can greatly reduce the confusion for code reading. For case 4, the logic of mpol_rebind_preferred() is confusing, as Michal Hocko pointed out: : I do believe that rebinding preferred policy is just bogus and it should : be dropped altogether on the ground that a preference is a mere hint from : userspace where to start the allocation. Unless I am missing something : cpusets will be always authoritative for the final placement. The : preferred node just acts as a starting point and it should be really : preserved when cpusets changes. Otherwise we have a very subtle behavior : corner cases. So dump all the tricky transformation between 'prefer' and 'local', and just record the new nodemask of rebinding. [feng.tang@intel.com: fix a problem in mpol_set_nodemask(), per Michal Hocko] Link: https://lkml.kernel.org/r/1622560492-1294-3-git-send-email-feng.tang@intel.com [feng.tang@intel.com: refine code and comments of mpol_set_nodemask(), per Michal] Link: https://lkml.kernel.org/r/20210603081807.GE56979@shbuild999.sh.intel.com Link: https://lkml.kernel.org/r/1622469956-82897-3-git-send-email-feng.tang@intel.com Signed-off-by: Feng Tang <feng.tang@intel.com> Suggested-by: Michal Hocko <mhocko@suse.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Ben Widawsky <ben.widawsky@intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm/mempolicy: cleanup nodemask intersection check for oomFeng Tang
Patch series "mm/mempolicy: some fix and semantics cleanup", v4. Current memory policy code has some confusing and ambiguous part about MPOL_LOCAL policy, as it is handled as a faked MPOL_PREFERRED one, and there are many places having to distinguish them. Also the nodemask intersection check needs cleanup to be more explicit for OOM use, and handle MPOL_INTERLEAVE correctly. This patchset cleans up these and unifies the parameter sanity check for mbind() and set_mempolicy(). This patch (of 3): mempolicy_nodemask_intersects seem to be a general purpose mempolicy function. In fact it is partially tailored for the OOM purpose instead. The oom proper is the only existing user so rename the function to make that purpose explicit. While at it drop the MPOL_INTERLEAVE as those allocations never has a nodemask defined (see alloc_page_interleave) so this is a dead code and a confusing one because MPOL_INTERLEAVE is a hint rather than a hard requirement so it shouldn't be considered during the OOM. The final code can be reduced to a check for MPOL_BIND which is the only memory policy that is a hard requirement and thus relevant to a constrained OOM logic. [mhocko@suse.com: changelog edits] Link: https://lkml.kernel.org/r/1622560492-1294-1-git-send-email-feng.tang@intel.com Link: https://lkml.kernel.org/r/1622560492-1294-2-git-send-email-feng.tang@intel.com Link: https://lkml.kernel.org/r/1622469956-82897-1-git-send-email-feng.tang@intel.com Link: https://lkml.kernel.org/r/1622469956-82897-2-git-send-email-feng.tang@intel.com Signed-off-by: Feng Tang <feng.tang@intel.com> Suggested-by: Michal Hocko <mhocko@suse.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Ben Widawsky <ben.widawsky@intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm/compaction: fix 'limit' in fast_isolate_freepagesWonhyuk Yang
Because of 'min(1, ...)', fast_isolate_freepages set 'limit' to 0 or 1. This takes away the opportunities of find candinate pages. So, by making enough scans available, increases the probability of finding the appropriate freepage. Tested it on the thpscale and the results are as follows. 5.12.0 5.12.0 valnilla patched Amean fault-both-1 598.15 ( 0.00%) 592.56 ( 0.93%) Amean fault-both-3 1494.47 ( 0.00%) 1514.35 ( -1.33%) Amean fault-both-5 2519.48 ( 0.00%) 2471.76 ( 1.89%) Amean fault-both-7 3173.85 ( 0.00%) 3079.19 ( 2.98%) Amean fault-both-12 8063.83 ( 0.00%) 7858.29 ( 2.55%) Amean fault-both-18 8781.20 ( 0.00%) 7827.70 * 10.86%* Amean fault-both-24 12576.44 ( 0.00%) 12250.20 ( 2.59%) Amean fault-both-30 18503.27 ( 0.00%) 17528.11 * 5.27%* Amean fault-both-32 16133.69 ( 0.00%) 13874.24 * 14.00%* 5.12.0 5.12.0 vanilla patched Ops Compaction migrate scanned 6547133.00 5963901.00 Ops Compaction free scanned 32452453.00 26609101.00 5.12 5.12 vanilla patched Duration User 27.99 28.84 Duration System 244.08 236.76 Duration Elapsed 78.27 78.38 Link: https://lkml.kernel.org/r/20210626082443.22547-1-vvghjk1234@gmail.com Fixes: 5a811889de10f ("mm, compaction: use free lists to quickly locate a migration target") Signed-off-by: Wonhyuk Yang <vvghjk1234@gmail.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm: compaction: remove duplicate !list_empty(&sublist) checkLiu Xiang
The list_splice_tail(&sublist, freelist) also do !list_empty(&sublist) check, so remove the duplicate call. Link: https://lkml.kernel.org/r/20210609095409.19920-1-liu.xiang@zlingsmart.com Signed-off-by: Liu Xiang <liu.xiang@zlingsmart.com> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm/compaction: use DEVICE_ATTR_WO macroYueHaibing
Use DEVICE_ATTR_WO helper instead of plain DEVICE_ATTR, which makes the code a bit shorter and easier to read. Link: https://lkml.kernel.org/r/20210523064521.32912-1-yuehaibing@huawei.com Signed-off-by: YueHaibing <yuehaibing@huawei.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm/zbud: don't export any zbud APIMiaohe Lin
The zbud doesn't need to export any API and it is meant to be used via zpool API since the commit 12d79d64bfd3 ("mm/zpool: update zswap to use zpool"). So we can remove the unneeded zbud.h and move down zpool API to avoid any forward declaration. [linmiaohe@huawei.com: fix unused function warnings when CONFIG_ZPOOL is disabled] Link: https://lkml.kernel.org/r/20210619025508.1239386-1-linmiaohe@huawei.com Link: https://lkml.kernel.org/r/20210608114515.206992-3-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Seth Jennings <sjenning@redhat.com> Cc: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm/zbud: reuse unbuddied[0] as buddied in zbud_poolMiaohe Lin
Patch series "Cleanups for zbud", v2. This series contains just cleanups to save some possible memory in zbud_pool and avoid exporting any unneeded zbud API. More details can be found in the respective changelogs This patch (of 2): Since commit 9d8c5b5284e4 ("mm: zbud: fix condition check on allocation size"), zbud_pool.unbuddied[0] is always unused. We can reuse it as buddied field to save some possible memory. Link: https://lkml.kernel.org/r/20210608114515.206992-1-linmiaohe@huawei.com Link: https://lkml.kernel.org/r/20210608114515.206992-2-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Dan Streetman <ddstreet@ieee.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-30mm/z3fold: use release_z3fold_page_locked() to release locked z3fold pageMiaohe Lin
We should use release_z3fold_page_locked() to release z3fold page when it's locked, although it looks harmless to use release_z3fold_page() now. Link: https://lkml.kernel.org/r/20210619093151.1492174-7-linmiaohe@huawei.com Fixes: dcf5aedb24f8 ("z3fold: stricter locking and more careful reclaim") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Vitaly Wool <vitaly.wool@konsulko.com> Cc: Hillf Danton <hdanton@sina.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
generated by cgit (git 2.34.1) at 2024-04-28 10:07:00 +0000