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refresh_zone_stat_thresholds function has two loops which is expensive for
higher number of CPUs and NUMA nodes.
Below is the rough estimation of total iterations done by these loops
based on number of NUMA and CPUs.
Total number of iterations: nCPU * 2 * Numa * mCPU
Where:
nCPU = total number of CPUs
Numa = total number of NUMA nodes
mCPU = mean value of total CPUs (e.g., 512 for 1024 total CPUs)
For the system under test with 16 NUMA nodes and 1024 CPUs, this results
in a substantial increase in the number of loop iterations during boot-up
when NUMA is enabled:
No NUMA = 1024*2*1*512 = 1,048,576 : Here refresh_zone_stat_thresholds
takes around 224 ms total for all the CPUs in the system under test.
16 NUMA = 1024*2*16*512 = 16,777,216 : Here refresh_zone_stat_thresholds
takes around 4.5 seconds total for all the CPUs in the system under test.
Calling this for each CPU is expensive when there are large number of CPUs
along with multiple NUMAs. Fix this by deferring
refresh_zone_stat_thresholds to be called later at once when all the
secondary CPUs are up. Also, register the DYN hooks to keep the existing
hotplug functionality intact.
Link: https://lkml.kernel.org/r/1723443220-20623-1-git-send-email-ssengar@linux.microsoft.com
Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Acked-by: Christoph Lameter <cl@linux.com>
Reviewed-by: Srivatsa S. Bhat (Microsoft) <srivatsa@csail.mit.edu>
Cc: Saurabh Singh Sengar <ssengar@microsoft.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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reclaim_folio_list uses a dummy reclaim_stat and is not being used. To
know the memory stat, add a new trace event. This is useful how how many
pages are not reclaimed or why.
This is an example:
mm_vmscan_reclaim_pages: nid=0 nr_scanned=112 nr_reclaimed=112 nr_dirty=0 nr_writeback=0 nr_congested=0 nr_immediate=0 nr_activate_anon=0 nr_activate_file=0 nr_ref_keep=0 nr_unmap_fail=0
Currently reclaim_folio_list is only called by reclaim_pages, and
reclaim_pages is used by damon and madvise. In the latest Android,
reclaim_pages is also used by shmem to reclaim all pages in a
address_space.
[jaewon31.kim@samsung.com: use sc.nr_scanned rather than new counting]
Link: https://lkml.kernel.org/r/20241016143227.961162-1-jaewon31.kim@samsung.com
Link: https://lkml.kernel.org/r/20241011124928.1224813-1-jaewon31.kim@samsung.com
Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Jaewon Kim <jaewon31.kim@samsung.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Commit 6471384af2a6 ("mm: security: introduce init_on_alloc=1 and
init_on_free=1 boot options") forces allocated page to be zeroed in
post_alloc_hook() when init_on_alloc=1.
For order-0 folios, if arch does not define
vma_alloc_zeroed_movable_folio(), the default implementation again zeros
the page return from the buddy allocator. So the page is zeroed twice.
Fix it by passing __GFP_ZERO instead to avoid double page zeroing. At the
moment, s390,arm64,x86,alpha,m68k are not impacted since they define their
own vma_alloc_zeroed_movable_folio().
For >0 order folios (mTHP and PMD THP), folio_zero_user() is called to
zero the folio again. Fix it by calling folio_zero_user() only if
init_on_alloc is set. All arch are impacted.
Add alloc_zeroed() helper to encapsulate the init_on_alloc check.
[ziy@nvidia.com: comment fixes, per David]
Link: https://lkml.kernel.org/r/97DB52E1-C594-49B5-9736-89AC302FAB01@nvidia.com
Link: https://lkml.kernel.org/r/20241011150304.709590-1-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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zswap_invalidation simply calls xa_erase, which acquires the Xarray lock
first, then does a look up. This has a higher overhead even if zswap is
not used or the tree is empty.
So instead, do a very lightweight xa_empty check first, if there is
nothing to erase, don't touch the lock or the tree.
Using xa_empty rather than zswap_never_enabled is more helpful as it cover
both case where zswap wes never used or the particular range doesn't have
any zswap entry. And it's safe as the swap slot should be currently
pinned by caller with HAS_CACHE.
Sequential SWAP in/out tests with zswap disabled showed a minor
performance gain, SWAP in of zero page with zswap enabled also showed a
performance gain. (swapout is basically unchanged so only test one case):
Swapout of 2G zero page using brd as SWAP, zswap disabled
(total time, 4 testrun, +0.1%):
Before: 1705013 us 1703119 us 1704335 us 1705848 us.
After: 1703579 us 1710640 us 1703625 us 1708699 us.
Swapin of 2G zero page using brd as SWAP, zswap disabled
(total time, 4 testrun, -3.5%):
Before: 1912312 us 1915692 us 1905837 us 1912706 us.
After: 1845354 us 1849691 us 1845868 us 1841828 us.
Swapin of 2G zero page using brd as SWAP, zswap enabled
(total time, 4 testrun, -3.3%):
Before: 1897994 us 1894681 us 1899982 us 1898333 us
After: 1835894 us 1834113 us 1832047 us 1833125 us
Swapin of 2G random page using brd as SWAP, zswap enabled
(total time, 4 testrun, -0.1%):
Before: 4519747 us 4431078 us 4430185 us 4439999 us
After: 4492176 us 4437796 us 4434612 us 4434289 us
And the performance is very slightly better or unchanged for
build kernel test with zswap enabled or disabled.
Build Linux Kernel with defconfig and -j32 in 1G memory cgroup,
using brd SWAP, zswap disabled (sys time in seconds, 6 testrun, -0.1%):
Before: 1648.83 1653.52 1666.34 1665.95 1663.06 1656.67
After: 1651.36 1661.89 1645.70 1657.45 1662.07 1652.83
Build Linux Kernel with defconfig and -j32 in 2G memory cgroup,
using brd SWAP zswap enabled (sys time in seconds, 6 testrun, -0.3%):
Before: 1240.25 1254.06 1246.77 1265.92 1244.23 1227.74
After: 1226.41 1218.21 1249.12 1249.13 1244.39 1233.01
Link: https://lkml.kernel.org/r/20241011171950.62684-1-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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When HVO is enabled and huge page memory allocs are made, the freed memory
can be aggregated into higher order memory in the following paths, which
facilitates further allocs for higher order memory.
echo 200000 > /proc/sys/vm/nr_hugepages
echo 200000 > /sys/devices/system/node/node*/hugepages/hugepages-2048kB/nr_hugepages
grub default_hugepagesz=2M hugepagesz=2M hugepages=200000
Currently not support for releasing aggregations to higher order in the
following way, which will releasing to lower order.
grub: default_hugepagesz=2M hugepagesz=2M hugepages=0:100000,1:100000
This patch supports the release of huge page optimizations aggregates to
higher order memory.
eg:
cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-xxx ... default_hugepagesz=2M hugepagesz=2M hugepages=0:100000,1:100000
Before:
Free pages count per migrate type at order 0 1 2 3 4 5 6 7 8 9 10
...
Node 0, zone Normal, type Unmovable 55282 97039 99307 0 1 1 0 1 1 1 0
Node 0, zone Normal, type Movable 25 11 345 87 48 21 2 20 9 3 75061
Node 0, zone Normal, type Reclaimable 4 2 2 4 3 0 2 1 1 1 0
Node 0, zone Normal, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
...
Free pages count per migrate type at order 0 1 2 3 4 5 6 7 8 9 10
Node 1, zone Normal, type Unmovable 98888 99650 99679 2 3 1 2 2 2 0 0
Node 1, zone Normal, type Movable 1 1 0 1 1 0 1 0 1 1 75937
Node 1, zone Normal, type Reclaimable 0 0 0 0 0 0 0 0 0 0 0
Node 1, zone Normal, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
After:
Free pages count per migrate type at order 0 1 2 3 4 5 6 7 8 9 10
...
Node 0, zone Normal, type Unmovable 152 158 37 2 2 0 3 4 2 6 717
Node 0, zone Normal, type Movable 1 37 53 3 55 49 16 6 2 1 75000
Node 0, zone Normal, type Reclaimable 1 4 3 1 2 1 1 1 1 1 0
Node 0, zone Normal, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
...
Free pages count per migrate type at order 0 1 2 3 4 5 6 7 8 9 10
Node 1, zone Normal, type Unmovable 5 3 2 1 3 4 2 2 2 0 779
Node 1, zone Normal, type Movable 1 0 1 1 1 0 1 0 1 1 75849
Node 1, zone Normal, type Reclaimable 0 0 0 0 0 0 0 0 0 0 0
Node 1, zone Normal, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
Link: https://lkml.kernel.org/r/20241012070802.1876-1-suhua1@kingsoft.com
Signed-off-by: suhua <suhua1@kingsoft.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The memcg stats are maintained in rstat infrastructure which provides very
fast updates side and reasonable read side. However memcg added plethora
of stats and made the read side, which is cgroup rstat flush, very slow.
To solve that, threshold was added in the memcg stats read side i.e. no
need to flush the stats if updates are within the threshold.
This threshold based improvement worked for sometime but more stats were
added to memcg and also the read codepath was getting triggered in the
performance sensitive paths which made threshold based ratelimiting
ineffective. We need more visibility into the hot and cold stats i.e.
stats with a lot of updates. Let's add trace to get that visibility.
[shakeel.butt@linux.dev: use unsigned long type for memcg_rstat_events, per Yosry]
Link: https://lkml.kernel.org/r/20241015213721.3804209-1-shakeel.butt@linux.dev
Link: https://lkml.kernel.org/r/20241010003550.3695245-1-shakeel.butt@linux.dev
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: T.J. Mercier <tjmercier@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: JP Kobryn <inwardvessel@gmail.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The hugepage parameter was deprecated since commit ddc1a5cbc05d
("mempolicy: alloc_pages_mpol() for NUMA policy without vma"), for
PMD-sized THP, it still tries only preferred node if possible in
vma_alloc_folio() by checking the order of the folio allocation.
Link: https://lkml.kernel.org/r/20241010061556.1846751-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Barry Song <baohua@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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When we do not set percpu_pagelist_high_fraction the kernel will compute
the pcp high_min/max by itself, which makes it hard to determine the
current high_min/max values.
So output the pcp high_min/max values to /proc/zoneinfo.
Link: https://lkml.kernel.org/r/20241010120935.656619-1-mengensun@tencent.com
Signed-off-by: MengEn Sun <mengensun@tencent.com>
Reviewed-by: Jinliang Zheng <alexjlzheng@tencent.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Replace "corresponding to the give pointer" with "corresponding to the
given pointer"
Link: https://lkml.kernel.org/r/20241010155439.554416-1-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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For clarity. It's increasingly hard to reason about the code, when KASLR
is moving around the boundaries. In this case where KASLR is randomizing
the location of the kernel image within physical memory, the maximum
number of address bits for physical memory has not changed.
What has changed is the ending address of memory that is allowed to be
directly mapped by the kernel.
Let's name the variable, and the associated macro accordingly.
Also, enhance the comment above the direct_map_physmem_end definition,
to further clarify how this all works.
Link: https://lkml.kernel.org/r/20241009025024.89813-1-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@amd.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Jordan Niethe <jniethe@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Introduce do_huge_zero_wp_pmd() to handle wp-fault on a hugezeropage and
replace it with a PMD-mapped THP. Remember to flush TLB entry
corresponding to the hugezeropage. In case of failure, fallback to
splitting the PMD.
Link: https://lkml.kernel.org/r/20241008061746.285961-3-dev.jain@arm.com
Signed-off-by: Dev Jain <dev.jain@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Lameter <cl@gentwo.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "Do not shatter hugezeropage on wp-fault", v7.
It was observed at [1] and [2] that the current kernel behaviour of
shattering a hugezeropage is inconsistent and suboptimal. For a VMA with
a THP allowable order, when we write-fault on it, the kernel installs a
PMD-mapped THP. On the other hand, if we first get a read fault, we get a
PMD pointing to the hugezeropage; subsequent write will trigger a
write-protection fault, shattering the hugezeropage into one writable
page, and all the other PTEs write-protected. The conclusion being, as
compared to the case of a single write-fault, applications have to suffer
512 extra page faults if they were to use the VMA as such, plus we get the
overhead of khugepaged trying to replace that area with a THP anyway.
Instead, replace the hugezeropage with a THP on wp-fault.
[1]: https://lore.kernel.org/all/3743d7e1-0b79-4eaf-82d5-d1ca29fe347d@arm.com/
[2]: https://lore.kernel.org/all/1cfae0c0-96a2-4308-9c62-f7a640520242@arm.com/
This patch (of 2):
In preparation for the second patch, abstract away the THP allocation
logic present in the create_huge_pmd() path, which corresponds to the
faulting case when no page is present.
There should be no functional change as a result of applying this patch,
except that, as David notes at [1], a PMD-aligned address should be passed
to update_mmu_cache_pmd().
[1]: https://lore.kernel.org/all/ddd3fcd2-48b3-4170-bcaa-2fe66e093f43@redhat.com/
Link: https://lkml.kernel.org/r/20241008061746.285961-1-dev.jain@arm.com
Link: https://lkml.kernel.org/r/20241008061746.285961-2-dev.jain@arm.com
Signed-off-by: Dev Jain <dev.jain@arm.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Lameter <cl@gentwo.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Fixes: d61ea1cb0095 ("userfaultfd: UFFD_FEATURE_WP_ASYNC")
Reported-by: Jeongjun Park <aha310510@gmail.com>
Closes: https://lkml.kernel.org/r/20241007065307.4158-1-aha310510@gmail.com
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Fixes the data race by moving the read to be behind the pcpu_lock. This
is okay because the code (initially) above it will not increase the
empty populated page count because it is populating backing pages that
already have allocations served out of them.
Link: https://lkml.kernel.org/r/20241008001942.8114-1-dennis@kernel.org
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202407191651.f24e499d-oliver.sang@intel.com
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "Unify hugetlb into arch_get_unmapped_area functions", v4.
This is an attempt to get rid of a fair amount of duplicated code wrt.
hugetlb and *get_unmapped_area* functions.
HugeTLB registers a .get_unmapped_area function which gets called from
__get_unmapped_area().
hugetlb_get_unmapped_area() is defined by a bunch of architectures and
it also has a generic definition for those that do not define it.
Short-long story is that there is a ton of duplicated code between
specific hugetlb *_get_unmapped_area_* functions and mm-core functions,
so we can do better by teaching arch_get_unmapped_area* functions how
to deal with hugetlb mappings.
Note that not a lot of things need to be taught though.
hugetlb_get_unmapped_area, that gets called for hugetlb mappings, runs
some sanity checks prior to calling mm_get_unmapped_area_vmflags(), so we
do not need to that down the road in the respective
{generic,arch}_get_unmapped_area* functions.
More information can be found in the respective patches.
LTP mmapstress hugetlb selftests were ran succesfully on:
This patch (of 9):
We want to stop special casing hugetlb mappings and make them go through
generic channels, so teach generic_get_unmapped_area{_topdown} to handle
those. The main difference is that we set info.align_mask for huge
mappings.
Link: https://lkml.kernel.org/r/20241007075037.267650-1-osalvador@suse.de
Link: https://lkml.kernel.org/r/20241007075037.267650-2-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Performance analysis using branch annotation on a fleet of 200 hosts
running web servers revealed that the 'unlikely' hint in
vms_gather_munmap_vmas() was 100% consistently incorrect. In all observed
cases, the branch behavior contradicted the hint.
Remove the 'unlikely' qualifier from the condition checking 'vms->uf'. By
doing so, we allow the compiler to make optimization decisions based on
its own heuristics and profiling data, rather than relying on a static
hint that has proven to be inaccurate in real-world scenarios.
Link: https://lkml.kernel.org/r/20241004164832.218681-1-leitao@debian.org
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Currently mapping_try_invalidate() and invalidate_inode_pages2_range()
traverses the xarray in batches and then for each batch, maintains and
sets the flag named xa_has_values if the batch has a shadow entry to clear
the entries at the end of the iteration.
However they forgot to reset the flag at the end of the iteration which
causes them to always try to clear the shadow entries in the subsequent
iterations where there might not be any shadow entries.
Fix this inefficiency.
Link: https://lkml.kernel.org/r/20241002225150.2334504-1-shakeel.butt@linux.dev
Fixes: 61c663e020d2 ("mm/truncate: batch-clear shadow entries")
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Yu Zhao <yuzhao@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In commit 246d3aa3e531 ("mm: cleanup count_mthp_stat() definition"), Ryan
Roberts has pointed out the merits of mm code that does not require THP,
to be compile-able without requiring THP ifdefs. As a step in that
direction, he has moved count_mthp_stat() to be always defined, resolving
to a no-op if THP is not defined.
Barry Song referred me to Ryan's commit when I was working on the "mm:
zswap swap-out of large folios" patch-series [1].
This patch propagates the benefits of the above change to page_io.c and
vmscan.c. As a result, there is one less reason to have the ifdef THP in
these code sections.
[1]: https://patchwork.kernel.org/project/linux-mm/list/?series=894347
Link: https://lkml.kernel.org/r/20241002225822.9006-1-kanchana.p.sridhar@intel.com
Signed-off-by: Kanchana P Sridhar <kanchana.p.sridhar@intel.com>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Wajdi Feghali <wajdi.k.feghali@intel.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Barry Song <21cnbao@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
We already have the folio here, so just use it, removing three hidden
calls to compound_head().
Link: https://lkml.kernel.org/r/20241002151403.1345296-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
All callers have been converted to use folio_test_ksm() or
PageAnonNotKsm(), so we can remove this wrapper.
Link: https://lkml.kernel.org/r/20241002152533.1350629-6-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Alex Shi <alexs@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Remove a call to PageKSM() by passing the folio containing tmp_page to
should_skip_rmap_item. Removes a hidden call to compound_head().
Link: https://lkml.kernel.org/r/20241002152533.1350629-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Alex Shi <alexs@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
By making try_to_merge_two_pages() and stable_tree_search() return a
folio, we can replace kpage with kfolio. This replaces 7 calls to
compound_head() with one.
[cuigaosheng1@huawei.com: add IS_ERR_OR_NULL check for stable_tree_search()]
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Link: https://lkml.kernel.org/r/20241002152533.1350629-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Alex Shi <alexs@kernel.org>
Cc: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "Remove PageKsm()".
The KSM flag is almost always tested on the folio rather than on the page.
This series removes the final users of PageKsm() and makes the flag only
This patch (of 5):
It is safe to use a folio here because all callers took a refcount on this
page. The one wrinkle is that we have to recalculate the value of folio
after splitting the page, since it has probably changed. Replaces nine
calls to compound_head() with one.
Link: https://lkml.kernel.org/r/20241002152533.1350629-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20241002152533.1350629-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Alex Shi <alexs@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Instead of using fs_initcall(), initialize sysfs with the rest of the
filesystem. This is the right way to do it because otherwise any error
during tmpfs_sysfs_init() would get silently ignored. It's also useful
if tmpfs' sysfs ever need to display runtime information.
Signed-off-by: André Almeida <andrealmeid@igalia.com>
Link: https://lore.kernel.org/r/20241101164251.327884-4-andrealmeid@igalia.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
DEVICE_STRING_ATTR_RO should be only used by device drivers since it
relies on `struct device` to use device_show_string() function. Using
this with non device code led to a kCFI violation:
> cat /sys/fs/tmpfs/features/casefold
[ 70.558496] CFI failure at kobj_attr_show+0x2c/0x4c (target: device_show_string+0x0/0x38; expected type: 0xc527b809)
Like the other filesystems, fix this by manually declaring the attribute
using kobj_attribute() and writing a proper show() function.
Also, leave macros for anyone that need to expand tmpfs sysfs' with
more attributes.
Fixes: 5132f08bd332 ("tmpfs: Expose filesystem features via sysfs")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Closes: https://lore.kernel.org/lkml/20241031051822.GA2947788@thelio-3990X/
Signed-off-by: André Almeida <andrealmeid@igalia.com>
Link: https://lore.kernel.org/r/20241101164251.327884-3-andrealmeid@igalia.com
Tested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
These three functions follow the same pattern. To deduplicate the code,
let's introduce a common helper __kmemdup_nul().
Link: https://lkml.kernel.org/r/20241007144911.27693-7-laoar.shao@gmail.com
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Cc: Simon Horman <horms@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Alejandro Colomar <alx@kernel.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@gmail.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Matus Jokay <matus.jokay@stuba.sk>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Ondrej Mosnacek <omosnace@redhat.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Quentin Monnet <qmo@kernel.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In kstrdup(), it is critical to ensure that the dest string is always
NUL-terminated. However, potential race condition can occur between a
writer and a reader.
Consider the following scenario involving task->comm:
reader writer
len = strlen(s) + 1;
strlcpy(tsk->comm, buf, sizeof(tsk->comm));
memcpy(buf, s, len);
In this case, there is a race condition between the reader and the writer.
The reader calculates the length of the string `s` based on the old value
of task->comm. However, during the memcpy(), the string `s` might be
updated by the writer to a new value of task->comm.
If the new task->comm is larger than the old one, the `buf` might not be
NUL-terminated. This can lead to undefined behavior and potential
security vulnerabilities.
Let's fix it by explicitly adding a NUL terminator after the memcpy. It
is worth noting that memcpy() is not atomic, so the new string can be
shorter when memcpy() already copied past the new NUL.
Link: https://lkml.kernel.org/r/20241007144911.27693-6-laoar.shao@gmail.com
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Cc: Alejandro Colomar <alx@kernel.org>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@gmail.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matus Jokay <matus.jokay@stuba.sk>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Ondrej Mosnacek <omosnace@redhat.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Quentin Monnet <qmo@kernel.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Simon Horman <horms@kernel.org>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
There is a unnecessary return statement at the end of void function
cma_activate_area. This can be dropped.
While at it, also fix another warning related to unsigned.
These are reported by checkpatch as well.
WARNING: Prefer 'unsigned int' to bare use of 'unsigned'
+unsigned cma_area_count;
WARNING: void function return statements are not generally useful
+ return;
+}
Link: https://lkml.kernel.org/r/20240927181637.19941-1-quic_pintu@quicinc.com
Signed-off-by: Pintu Kumar <quic_pintu@quicinc.com>
Cc: Pintu Agarwal <pintu.ping@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The kernel invalidates the page cache in batches of PAGEVEC_SIZE. For
each batch, it traverses the page cache tree and collects the entries
(folio and shadow entries) in the struct folio_batch. For the shadow
entries present in the folio_batch, it has to traverse the page cache tree
for each individual entry to remove them. This patch optimize this by
removing them in a single tree traversal.
To evaluate the changes, we created 200GiB file on a fuse fs and in a
memcg. We created the shadow entries by triggering reclaim through
memory.reclaim in that specific memcg and measure the simple
fadvise(DONTNEED) operation.
# time xfs_io -c 'fadvise -d 0 ${file_size}' file
time (sec)
Without 5.12 +- 0.061
With-patch 4.19 +- 0.086 (18.16% decrease)
Link: https://lkml.kernel.org/r/20240925224716.2904498-3-shakeel.butt@linux.dev
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Chris Mason <clm@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm: optimize shadow entries removal", v2.
Some of our production workloads which processes a large amount of data
spends considerable amount of CPUs on truncation and invalidation of large
sized files (100s of GiBs of size). Tracing the operations showed that
most of the time is in shadow entries removal. This patch series
optimizes the truncation and invalidation operations.
This patch (of 2):
The kernel truncates the page cache in batches of PAGEVEC_SIZE. For each
batch, it traverses the page cache tree and collects the entries (folio
and shadow entries) in the struct folio_batch. For the shadow entries
present in the folio_batch, it has to traverse the page cache tree for
each individual entry to remove them. This patch optimize this by
removing them in a single tree traversal.
On large machines in our production which run workloads manipulating large
amount of data, we have observed that a large amount of CPUs are spent on
truncation of very large files (100s of GiBs file sizes). More
specifically most of time was spent on shadow entries cleanup, so
optimizing the shadow entries cleanup, even a little bit, has good impact.
To evaluate the changes, we created 200GiB file on a fuse fs and in a
memcg. We created the shadow entries by triggering reclaim through
memory.reclaim in that specific memcg and measure the simple truncation
operation.
# time truncate -s 0 file
time (sec)
Without 5.164 +- 0.059
With-patch 4.21 +- 0.066 (18.47% decrease)
Link: https://lkml.kernel.org/r/20240925224716.2904498-1-shakeel.butt@linux.dev
Link: https://lkml.kernel.org/r/20240925224716.2904498-2-shakeel.butt@linux.dev
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Chris Mason <clm@fb.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Bits of LRU_REFS_MASK are not inherited during migration which lead to new
folio start from tier0 when MGLRU enabled. Try to bring as much bits of
folio->flags as possible since compaction and alloc_contig_range which
introduce migration do happen at times.
Link: https://lkml.kernel.org/r/20240926050647.5653-1-zhaoyang.huang@unisoc.com
Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
Suggested-by: Yu Zhao <yuzhao@google.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Now no users are using the pte_offset_map_nolock(), remove it.
Link: https://lkml.kernel.org/r/d04f9bbbcde048fb6ffa6f2bdbc6f9b22d5286f9.1727332572.git.zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In walk_pte_range(), we may modify the pte entry after holding the ptl, so
convert it to using pte_offset_map_rw_nolock(). At this time, the
pte_same() check is not performed after the ptl held, so we should get
pmdval and do pmd_same() check to ensure the stability of pmd entry.
Link: https://lkml.kernel.org/r/7e9c194a5efacc9609cfd31abb9c7df88b53b530.1727332572.git.zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In move_pages_pte(), we may modify the dst_pte and src_pte after acquiring
the ptl, so convert it to using pte_offset_map_rw_nolock(). But since we
will use pte_same() to detect the change of the pte entry, there is no
need to get pmdval, so just pass a dummy variable to it.
Link: https://lkml.kernel.org/r/1530e8fdbfc72eacf3b095babe139ce3d715600a.1727332572.git.zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In the caller of map_pte(), we may modify the pvmw->pte after acquiring
the pvmw->ptl, so convert it to using pte_offset_map_rw_nolock(). At this
time, the pte_same() check is not performed after the pvmw->ptl held, so
we should get pmdval and do pmd_same() check to ensure the stability of
pvmw->pmd.
Link: https://lkml.kernel.org/r/2620a48f34c9f19864ab0169cdbf253d31a8fcaa.1727332572.git.zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In move_ptes(), we may modify the new_pte after acquiring the new_ptl, so
convert it to using pte_offset_map_rw_nolock(). Now new_pte is none, so
hpage_collapse_scan_file() path can not find this by traversing
file->f_mapping, so there is no concurrency with retract_page_tables().
In addition, we already hold the exclusive mmap_lock, so this new_pte page
is stable, so there is no need to get pmdval and do pmd_same() check.
Link: https://lkml.kernel.org/r/9d582a09dbcf12e562ac5fe0ba05e9248a58f5e0.1727332572.git.zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In copy_pte_range(), we may modify the src_pte entry after holding the
src_ptl, so convert it to using pte_offset_map_rw_nolock(). Since we
already hold the exclusive mmap_lock, and the copy_pte_range() and
retract_page_tables() are using vma->anon_vma to be exclusive, so the PTE
page is stable, there is no need to get pmdval and do pmd_same() check.
Link: https://lkml.kernel.org/r/9166f6fad806efbca72e318ab6f0f8af458056a9.1727332572.git.zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In collapse_pte_mapped_thp(), we may modify the pte and pmd entry after
acquiring the ptl, so convert it to using pte_offset_map_rw_nolock(). At
this time, the pte_same() check is not performed after the PTL held. So
we should get pgt_pmd and do pmd_same() check after the ptl held.
Link: https://lkml.kernel.org/r/055e42db68da00ac8ecab94bd2633c7cd965eb1c.1727332572.git.zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In handle_pte_fault(), we may modify the vmf->pte after acquiring the
vmf->ptl, so convert it to using pte_offset_map_rw_nolock(). But since we
will do the pte_same() check, so there is no need to get pmdval to do
pmd_same() check, just pass a dummy variable to it.
Link: https://lkml.kernel.org/r/af8d694853b44c5a6018403ae435440e275854c7.1727332572.git.zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
In __collapse_huge_page_swapin(), we just use the ptl for pte_same() check
in do_swap_page(). In other places, we directly use
pte_offset_map_lock(), so convert it to using pte_offset_map_ro_nolock().
Link: https://lkml.kernel.org/r/dc97a6c3cb9ea80cab30c5626eeea79959d93258.1727332572.git.zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In filemap_fault_recheck_pte_none(), we just do pte_none() check, so
convert it to using pte_offset_map_ro_nolock().
Link: https://lkml.kernel.org/r/9f7cbbaa772385ced1b8931b67a8b9d246c9b82d.1727332572.git.zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "introduce pte_offset_map_{ro|rw}_nolock()", v5.
As proposed by David Hildenbrand [1], this series introduces the following
two new helper functions to replace pte_offset_map_nolock().
1. pte_offset_map_ro_nolock()
2. pte_offset_map_rw_nolock()
As the name suggests, pte_offset_map_ro_nolock() is used for read-only
case. In this case, only read-only operations will be performed on PTE
page after the PTL is held. The RCU lock in pte_offset_map_nolock() will
ensure that the PTE page will not be freed, and there is no need to worry
about whether the pmd entry is modified. Therefore
pte_offset_map_ro_nolock() is just a renamed version of
pte_offset_map_nolock().
pte_offset_map_rw_nolock() is used for may-write case. In this case, the
pte or pmd entry may be modified after the PTL is held, so we need to
ensure that the pmd entry has not been modified concurrently. So in
addition to the name change, it also outputs the pmdval when successful.
The users should make sure the page table is stable like checking
pte_same() or checking pmd_same() by using the output pmdval before
performing the write operations.
This series will convert all pte_offset_map_nolock() into the above two
helper functions one by one, and finally completely delete it.
This also a preparation for reclaiming the empty user PTE page table
pages.
This patch (of 13):
Currently, the usage of pte_offset_map_nolock() can be divided into the
following two cases:
1) After acquiring PTL, only read-only operations are performed on the PTE
page. In this case, the RCU lock in pte_offset_map_nolock() will ensure
that the PTE page will not be freed, and there is no need to worry
about whether the pmd entry is modified.
2) After acquiring PTL, the pte or pmd entries may be modified. At this
time, we need to ensure that the pmd entry has not been modified
concurrently.
To more clearing distinguish between these two cases, this commit
introduces two new helper functions to replace pte_offset_map_nolock().
For 1), just rename it to pte_offset_map_ro_nolock(). For 2), in addition
to changing the name to pte_offset_map_rw_nolock(), it also outputs the
pmdval when successful. It is applicable for may-write cases where any
modification operations to the page table may happen after the
corresponding spinlock is held afterwards. But the users should make sure
the page table is stable like checking pte_same() or checking pmd_same()
by using the output pmdval before performing the write operations.
Note: "RO" / "RW" expresses the intended semantics, not that the *kmap*
will be read-only/read-write protected.
Subsequent commits will convert pte_offset_map_nolock() into the above
two functions one by one, and finally completely delete it.
Link: https://lkml.kernel.org/r/cover.1727332572.git.zhengqi.arch@bytedance.com
Link: https://lkml.kernel.org/r/5aeecfa131600a454b1f3a038a1a54282ca3b856.1727332572.git.zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The types of mm flags are now far beyond the core dump related features.
This patch moves mm flags from linux/sched/coredump.h to linux/mm_types.h.
The linux/sched/coredump.h has include the mm_types.h, so the C files
related to coredump does not need to change head file inclusion. In
addition, the inclusion of sched/coredump.h now can be deleted from the C
files that irrelevant to core dump.
Link: https://lkml.kernel.org/r/20240926074922.2721274-1-sunnanyong@huawei.com
Signed-off-by: Nanyong Sun <sunnanyong@huawei.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The process_madvise() call was introduced in commit ecb8ac8b1f14
("mm/madvise: introduce process_madvise() syscall: an external memory
hinting API") as a means of performing madvise() operations on another
process.
However, as it provides the means by which to perform multiple madvise()
operations in a batch via an iovec, it is useful to utilise the same
interface for performing operations on the current process rather than a
remote one.
Commit 22af8caff7d1 ("mm/madvise: process_madvise() drop capability check
if same mm") removed the need for a caller invoking process_madvise() on
its own pidfd to possess the CAP_SYS_NICE capability, however this leaves
the restrictions on operation in place.
Resolve this by only applying the restriction on operations when accessing
a remote process.
Moving forward we plan to implement a simpler means of specifying this
condition other than needing to establish a self pidfd, perhaps in the
form of a sentinel pidfd.
Also take the opportunity to refactor the system call implementation
abstracting the vectorised operation.
Link: https://lkml.kernel.org/r/20240926151019.82902-1-lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christian Brauner <brauner@kernel.org>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Fix typo in mempolicy.h and Correct the number of allowed memory policy
Link: https://lkml.kernel.org/r/20240926183516.4034-2-tanyaagarwal25699@gmail.com
Signed-off-by: Tanya Agarwal <tanyaagarwal25699@gmail.com>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Cc: Anup Sharma <anupnewsmail@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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It is needed to ensure sc->nr.unqueued_dirty > 0, which can avoid setting
PGDAT_DIRTY flag when sc->nr.unqueued_dirty and sc->nr.file_taken are both
zero.
Link: https://lkml.kernel.org/r/20240112012353.1387-1-justinjiang@vivo.com
Signed-off-by: Zhiguo Jiang <justinjiang@vivo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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mm_access() can return NULL if the mm is not found, but this is handled
the same as an error in all callers, with some translating this into an
-ESRCH error.
Only proc_mem_open() returns NULL if no mm is found, however in this case
it is clearer and makes more sense to explicitly handle the error.
Additionally we take the opportunity to refactor the function to eliminate
unnecessary nesting.
Simplify things by simply returning -ESRCH if no mm is found - this both
eliminates confusing use of the IS_ERR_OR_NULL() macro, and simplifies
callers which would return -ESRCH by returning this error directly.
[lorenzo.stoakes@oracle.com: prefer neater pointer error comparison]
Link: https://lkml.kernel.org/r/2fae1834-749a-45e1-8594-5e5979cf7103@lucifer.local
Link: https://lkml.kernel.org/r/20240924201023.193135-1-lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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into one operation
When compiling kernel source 'make -j $(nproc)' with the up-and-running
KASAN-enabled kernel on a 256-core machine, the following soft lockup is
shown:
watchdog: BUG: soft lockup - CPU#28 stuck for 22s! [kworker/28:1:1760]
CPU: 28 PID: 1760 Comm: kworker/28:1 Kdump: loaded Not tainted 6.10.0-rc5 #95
Workqueue: events drain_vmap_area_work
RIP: 0010:smp_call_function_many_cond+0x1d8/0xbb0
Code: 38 c8 7c 08 84 c9 0f 85 49 08 00 00 8b 45 08 a8 01 74 2e 48 89 f1 49 89 f7 48 c1 e9 03 41 83 e7 07 4c 01 e9 41 83 c7 03 f3 90 <0f> b6 01 41 38 c7 7c 08 84 c0 0f 85 d4 06 00 00 8b 45 08 a8 01 75
RSP: 0018:ffffc9000cb3fb60 EFLAGS: 00000202
RAX: 0000000000000011 RBX: ffff8883bc4469c0 RCX: ffffed10776e9949
RDX: 0000000000000002 RSI: ffff8883bb74ca48 RDI: ffffffff8434dc50
RBP: ffff8883bb74ca40 R08: ffff888103585dc0 R09: ffff8884533a1800
R10: 0000000000000004 R11: ffffffffffffffff R12: ffffed1077888d39
R13: dffffc0000000000 R14: ffffed1077888d38 R15: 0000000000000003
FS: 0000000000000000(0000) GS:ffff8883bc400000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005577b5c8d158 CR3: 0000000004850000 CR4: 0000000000350ef0
Call Trace:
<IRQ>
? watchdog_timer_fn+0x2cd/0x390
? __pfx_watchdog_timer_fn+0x10/0x10
? __hrtimer_run_queues+0x300/0x6d0
? sched_clock_cpu+0x69/0x4e0
? __pfx___hrtimer_run_queues+0x10/0x10
? srso_return_thunk+0x5/0x5f
? ktime_get_update_offsets_now+0x7f/0x2a0
? srso_return_thunk+0x5/0x5f
? srso_return_thunk+0x5/0x5f
? hrtimer_interrupt+0x2ca/0x760
? __sysvec_apic_timer_interrupt+0x8c/0x2b0
? sysvec_apic_timer_interrupt+0x6a/0x90
</IRQ>
<TASK>
? asm_sysvec_apic_timer_interrupt+0x16/0x20
? smp_call_function_many_cond+0x1d8/0xbb0
? __pfx_do_kernel_range_flush+0x10/0x10
on_each_cpu_cond_mask+0x20/0x40
flush_tlb_kernel_range+0x19b/0x250
? srso_return_thunk+0x5/0x5f
? kasan_release_vmalloc+0xa7/0xc0
purge_vmap_node+0x357/0x820
? __pfx_purge_vmap_node+0x10/0x10
__purge_vmap_area_lazy+0x5b8/0xa10
drain_vmap_area_work+0x21/0x30
process_one_work+0x661/0x10b0
worker_thread+0x844/0x10e0
? srso_return_thunk+0x5/0x5f
? __kthread_parkme+0x82/0x140
? __pfx_worker_thread+0x10/0x10
kthread+0x2a5/0x370
? __pfx_kthread+0x10/0x10
ret_from_fork+0x30/0x70
? __pfx_kthread+0x10/0x10
ret_from_fork_asm+0x1a/0x30
</TASK>
Debugging Analysis:
1. The following ftrace log shows that the lockup CPU spends too much
time iterating vmap_nodes and flushing TLB when purging vm_area
structures. (Some info is trimmed).
kworker: funcgraph_entry: | drain_vmap_area_work() {
kworker: funcgraph_entry: | mutex_lock() {
kworker: funcgraph_entry: 1.092 us | __cond_resched();
kworker: funcgraph_exit: 3.306 us | }
... ...
kworker: funcgraph_entry: | flush_tlb_kernel_range() {
... ...
kworker: funcgraph_exit: # 7533.649 us | }
... ...
kworker: funcgraph_entry: 2.344 us | mutex_unlock();
kworker: funcgraph_exit: $ 23871554 us | }
The drain_vmap_area_work() spends over 23 seconds.
There are 2805 flush_tlb_kernel_range() calls in the ftrace log.
* One is called in __purge_vmap_area_lazy().
* Others are called by purge_vmap_node->kasan_release_vmalloc.
purge_vmap_node() iteratively releases kasan vmalloc
allocations and flushes TLB for each vmap_area.
- [Rough calculation] Each flush_tlb_kernel_range() runs
about 7.5ms.
-- 2804 * 7.5ms = 21.03 seconds.
-- That's why a soft lock is triggered.
2. Extending the soft lockup time can work around the issue (For example,
# echo 60 > /proc/sys/kernel/watchdog_thresh). This confirms the
above-mentioned speculation: drain_vmap_area_work() spends too much
time.
If we combine all TLB flush operations of the KASAN shadow virtual
address into one operation in the call path
'purge_vmap_node()->kasan_release_vmalloc()', the running time of
drain_vmap_area_work() can be saved greatly. The idea is from the
flush_tlb_kernel_range() call in __purge_vmap_area_lazy(). And, the
soft lockup won't be triggered.
Here is the test result based on 6.10:
[6.10 wo/ the patch]
1. ftrace latency profiling (record a trace if the latency > 20s).
echo 20000000 > /sys/kernel/debug/tracing/tracing_thresh
echo drain_vmap_area_work > /sys/kernel/debug/tracing/set_graph_function
echo function_graph > /sys/kernel/debug/tracing/current_tracer
echo 1 > /sys/kernel/debug/tracing/tracing_on
2. Run `make -j $(nproc)` to compile the kernel source
3. Once the soft lockup is reproduced, check the ftrace log:
cat /sys/kernel/debug/tracing/trace
# tracer: function_graph
#
# CPU DURATION FUNCTION CALLS
# | | | | | | |
76) $ 50412985 us | } /* __purge_vmap_area_lazy */
76) $ 50412997 us | } /* drain_vmap_area_work */
76) $ 29165911 us | } /* __purge_vmap_area_lazy */
76) $ 29165926 us | } /* drain_vmap_area_work */
91) $ 53629423 us | } /* __purge_vmap_area_lazy */
91) $ 53629434 us | } /* drain_vmap_area_work */
91) $ 28121014 us | } /* __purge_vmap_area_lazy */
91) $ 28121026 us | } /* drain_vmap_area_work */
[6.10 w/ the patch]
1. Repeat step 1-2 in "[6.10 wo/ the patch]"
2. The soft lockup is not triggered and ftrace log is empty.
cat /sys/kernel/debug/tracing/trace
# tracer: function_graph
#
# CPU DURATION FUNCTION CALLS
# | | | | | | |
3. Setting 'tracing_thresh' to 10/5 seconds does not get any ftrace
log.
4. Setting 'tracing_thresh' to 1 second gets ftrace log.
cat /sys/kernel/debug/tracing/trace
# tracer: function_graph
#
# CPU DURATION FUNCTION CALLS
# | | | | | | |
23) $ 1074942 us | } /* __purge_vmap_area_lazy */
23) $ 1074950 us | } /* drain_vmap_area_work */
The worst execution time of drain_vmap_area_work() is about 1 second.
Link: https://lore.kernel.org/lkml/ZqFlawuVnOMY2k3E@pc638.lan/
Link: https://lkml.kernel.org/r/20240726165246.31326-1-ahuang12@lenovo.com
Fixes: 282631cb2447 ("mm: vmalloc: remove global purge_vmap_area_root rb-tree")
Signed-off-by: Adrian Huang <ahuang12@lenovo.com>
Co-developed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Tested-by: Jiwei Sun <sunjw10@lenovo.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In proactive memory reclamation scenarios, it is necessary to estimate the
pswpin and pswpout metrics of the cgroup to determine whether to continue
reclaiming anonymous pages in the current batch. This patch will collect
these metrics and expose them.
[linuszeng@tencent.com: v2]
Link: https://lkml.kernel.org/r/20240830082244.156923-1-jingxiangzeng.cas@gmail.com
Li nk: https://lkml.kernel.org/r/20240913084453.3605621-1-jingxiangzeng.cas@gmail.com
Link: https://lkml.kernel.org/r/20240830082244.156923-1-jingxiangzeng.cas@gmail.com
Signed-off-by: Jingxiang Zeng <linuszeng@tencent.com>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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sparse warns about zero initializing an array with {0,}, change it to
the equivalent {0}.
Fixes the sparse warning:
mm/damon/tests/vaddr-kunit.h:69:47: warning: missing braces around initializer
Link: https://lkml.kernel.org/r/xriwklcwjpwcz7eiavo6f7envdar4jychhsk6sfkj5klaznb6b@j6vrvr2sxjht
Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests")
Signed-off-by: Leo Stone <leocstone@gmail.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Jinjie Ruan <ruanjinjie@huawei.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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