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Let's update the documentation that any signal is sufficient, and add a
comment that not only checking for fatal signals is historical baggage:
changing it now could break existing user space. although unlikely.
For example, when an app provides a custom SIGALRM handler and triggers
memory offlining, the timeout cmd would no longer stop memory offlining,
because SIGALRM would no longer be considered a fatal signal.
Note that using signal_pending() instead of fatal_signal_pending() is
an anti-pattern, but slowly deprecating that behavior to eventually
change it in the far future is probably not worth the effort. If this
ever becomes relevant for user-space, we might want to rethink.
Link: https://lkml.kernel.org/r/20230711174050.603820-1-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The only caller of check_for_memory() is free_area_init(), which is
annotated with __init, so it should be safe to also mark the former as
__init.
Link: https://lkml.kernel.org/r/20230710093750.1294-1-haifeng.xu@shopee.com
Signed-off-by: Haifeng Xu <haifeng.xu@shopee.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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obj_tagged() is not needed at this point, because objects can only have
one tag: OBJ_ALLOCATED_TAG. We needed obj_tagged() for the zsmalloc LRU
implementation, which has now been removed. Simplify zsmalloc code and
revert to the previous implementation that was in place before the
zsmalloc LRU series.
Link: https://lkml.kernel.org/r/20230709025817.3842416-1-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The behavior here is the same as it is for anon/shmem. This is done
separately because hugetlb pte marker handling is a bit different.
Link: https://lkml.kernel.org/r/20230707215540.2324998-6-axelrasmussen@google.com
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
Acked-by: Peter Xu <peterx@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gaosheng Cui <cuigaosheng1@huawei.com>
Cc: Huang, Ying <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Jan Alexander Steffens (heftig) <heftig@archlinux.org>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: ZhangPeng <zhangpeng362@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Smatch has observed that pte_offset_map_lock() is now allowed to fail, and
then ptl should not be unlocked. Use -EAGAIN here like elsewhere.
Link: https://lkml.kernel.org/r/bc7bba61-d34f-ad3a-ccf1-c191585ef851@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Axel Rasmussen <axelrasmussen@google.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The basic idea here is to "simulate" memory poisoning for VMs. A VM
running on some host might encounter a memory error, after which some
page(s) are poisoned (i.e., future accesses SIGBUS). They expect that
once poisoned, pages can never become "un-poisoned". So, when we live
migrate the VM, we need to preserve the poisoned status of these pages.
When live migrating, we try to get the guest running on its new host as
quickly as possible. So, we start it running before all memory has been
copied, and before we're certain which pages should be poisoned or not.
So the basic way to use this new feature is:
- On the new host, the guest's memory is registered with userfaultfd, in
either MISSING or MINOR mode (doesn't really matter for this purpose).
- On any first access, we get a userfaultfd event. At this point we can
communicate with the old host to find out if the page was poisoned.
- If so, we can respond with a UFFDIO_POISON - this places a swap marker
so any future accesses will SIGBUS. Because the pte is now "present",
future accesses won't generate more userfaultfd events, they'll just
SIGBUS directly.
UFFDIO_POISON does not handle unmapping previously-present PTEs. This
isn't needed, because during live migration we want to intercept all
accesses with userfaultfd (not just writes, so WP mode isn't useful for
this). So whether minor or missing mode is being used (or both), the PTE
won't be present in any case, so handling that case isn't needed.
Similarly, UFFDIO_POISON won't replace existing PTE markers. This might
be okay to do, but it seems to be safer to just refuse to overwrite any
existing entry (like a UFFD_WP PTE marker).
Link: https://lkml.kernel.org/r/20230707215540.2324998-5-axelrasmussen@google.com
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
Acked-by: Peter Xu <peterx@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gaosheng Cui <cuigaosheng1@huawei.com>
Cc: Huang, Ying <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Jan Alexander Steffens (heftig) <heftig@archlinux.org>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: ZhangPeng <zhangpeng362@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This code is already duplicated twice, and UFFDIO_POISON will do the same
check a third time. So, it's worth extracting into a helper to save
repetitive lines of code.
Link: https://lkml.kernel.org/r/20230707215540.2324998-4-axelrasmussen@google.com
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gaosheng Cui <cuigaosheng1@huawei.com>
Cc: Huang, Ying <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Jan Alexander Steffens (heftig) <heftig@archlinux.org>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: ZhangPeng <zhangpeng362@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "add UFFDIO_POISON to simulate memory poisoning with UFFD",
v4.
This series adds a new userfaultfd feature, UFFDIO_POISON. See commit 4
for a detailed description of the feature.
This patch (of 8):
Future patches will reuse PTE_MARKER_SWAPIN_ERROR to implement
UFFDIO_POISON, so make some various preparations for that:
First, rename it to just PTE_MARKER_POISONED. The "SWAPIN" can be
confusing since we're going to re-use it for something not really related
to swap. This can be particularly confusing for things like hugetlbfs,
which doesn't support swap whatsoever. Also rename some various helper
functions.
Next, fix pte marker copying for hugetlbfs. Previously, it would WARN on
seeing a PTE_MARKER_SWAPIN_ERROR, since hugetlbfs doesn't support swap.
But, since we're going to re-use it, we want it to go ahead and copy it
just like non-hugetlbfs memory does today. Since the code to do this is
more complicated now, pull it out into a helper which can be re-used in
both places. While we're at it, also make it slightly more explicit in
its handling of e.g. uffd wp markers.
For non-hugetlbfs page faults, instead of returning VM_FAULT_SIGBUS for an
error entry, return VM_FAULT_HWPOISON. For most cases this change doesn't
matter, e.g. a userspace program would receive a SIGBUS either way. But
for UFFDIO_POISON, this change will let KVM guests get an MCE out of the
box, instead of giving a SIGBUS to the hypervisor and requiring it to
somehow inject an MCE.
Finally, for hugetlbfs faults, handle PTE_MARKER_POISONED, and return
VM_FAULT_HWPOISON_LARGE in such cases. Note that this can't happen today
because the lack of swap support means we'll never end up with such a PTE
anyway, but this behavior will be needed once such entries *can* show up
via UFFDIO_POISON.
Link: https://lkml.kernel.org/r/20230707215540.2324998-1-axelrasmussen@google.com
Link: https://lkml.kernel.org/r/20230707215540.2324998-2-axelrasmussen@google.com
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
Acked-by: Peter Xu <peterx@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gaosheng Cui <cuigaosheng1@huawei.com>
Cc: Huang, Ying <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Jan Alexander Steffens (heftig) <heftig@archlinux.org>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: T.J. Alumbaugh <talumbau@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: ZhangPeng <zhangpeng362@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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MEM_CGROUP_ID_MAX is only used when CONFIG_MEMCG is configured. So remove
unneeded !CONFIG_MEMCG variant. Also it's only used in
mem_cgroup_alloc(), so move it from memcontrol.h to memcontrol.c. And
further define it as:
#define MEM_CGROUP_ID_MAX ((1UL << MEM_CGROUP_ID_SHIFT) - 1)
so if someone changes MEM_CGROUP_ID_SHIFT in the future, then
MEM_CGROUP_ID_MAX will be updated accordingly, as suggested by Muchun.
Link: https://lkml.kernel.org/r/20230708023304.1184111-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Saves one implicit call to compound_head().
Link: https://lkml.kernel.org/r/20230706163847.403202-4-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: ZhangPeng <zhangpeng362@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Saves three implicit calls to compound_head().
Link: https://lkml.kernel.org/r/20230706163847.403202-3-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: ZhangPeng <zhangpeng362@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Saves six implicit calls to compound_head().
Link: https://lkml.kernel.org/r/20230706163847.403202-2-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: ZhangPeng <zhangpeng362@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Saves one implicit call to compound_head().
Link: https://lkml.kernel.org/r/20230706163847.403202-1-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: ZhangPeng <zhangpeng362@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The local variable @page in __split_vmemmap_huge_pmd() to obtain a pmd
page without holding page_table_lock may possiblely get the page table
page instead of a huge pmd page.
The effect may be in set_pte_at() since we may pass an invalid page
struct, if set_pte_at() wants to access the page struct (e.g.
CONFIG_PAGE_TABLE_CHECK is enabled), it may crash the kernel.
So fix it. And inline __split_vmemmap_huge_pmd() since it only has one
user.
Link: https://lkml.kernel.org/r/20230707033859.16148-1-songmuchun@bytedance.com
Fixes: d8d55f5616cf ("mm: sparsemem: use page table lock to protect kernel pmd operations")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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next_present_section_nr() has already ensured that
'section_nr<=__highest_present_section_nr', so this check is removed.
Link: https://lkml.kernel.org/r/20230707060501.29184-1-liuq131@chinatelecom.cn
Signed-off-by: liuq <liuq131@chinatelecom.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Just like commit 9721fd82351d ("mm: compaction: skip memory hole
rapidly when isolating migratable pages"), I can see it will also take
more time to skip the larger memory hole (range: 0x1000000000 -
0x1800000000) when isolating free pages on my machine with below memory
layout. So like commit 9721fd82351d, adding a new helper to skip the
memory hole rapidly, which can reduce the time consumed from about 70us
to less than 1us.
[ 0.000000] Zone ranges:
[ 0.000000] DMA [mem 0x0000000040000000-0x00000000ffffffff]
[ 0.000000] DMA32 empty
[ 0.000000] Normal [mem 0x0000000100000000-0x0000001fa7ffffff]
[ 0.000000] Movable zone start for each node
[ 0.000000] Early memory node ranges
[ 0.000000] node 0: [mem 0x0000000040000000-0x0000000fffffffff]
[ 0.000000] node 0: [mem 0x0000001800000000-0x0000001fa3c7ffff]
[ 0.000000] node 0: [mem 0x0000001fa3c80000-0x0000001fa3ffffff]
[ 0.000000] node 0: [mem 0x0000001fa4000000-0x0000001fa402ffff]
[ 0.000000] node 0: [mem 0x0000001fa4030000-0x0000001fa40effff]
[ 0.000000] node 0: [mem 0x0000001fa40f0000-0x0000001fa73cffff]
[ 0.000000] node 0: [mem 0x0000001fa73d0000-0x0000001fa745ffff]
[ 0.000000] node 0: [mem 0x0000001fa7460000-0x0000001fa746ffff]
[ 0.000000] node 0: [mem 0x0000001fa7470000-0x0000001fa758ffff]
[ 0.000000] node 0: [mem 0x0000001fa7590000-0x0000001fa7ffffff]
[shikemeng@huaweicloud.com: avoid missing last page block in section after skip offline sections]
Link: https://lkml.kernel.org/r/20230804110454.2935878-1-shikemeng@huaweicloud.com
Link: https://lkml.kernel.org/r/20230804110454.2935878-2-shikemeng@huaweicloud.com
Link: https://lkml.kernel.org/r/d2ba7e41ee566309b594311207ffca736375fc16.1688715750.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Use the page->buddy_list instead of page->lru to clarify the correct type
of list for free pages.
Link: https://lkml.kernel.org/r/b21cd8e2e32b9a1d9bc9e43ebf8acaf35e87f8df.1688715750.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Huang, Ying <ying.huang@intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Add description of @mm_wr_locked and @mm.
to silence the warnings:
mm/memory.c:1716: warning: Function parameter or member 'mm_wr_locked' not described in 'unmap_vmas'
mm/memory.c:5110: warning: Function parameter or member 'mm' not described in 'mm_account_fault'
Link: https://lkml.kernel.org/r/20230707090034.125511-1-yang.lee@linux.alibaba.com
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Commit 2aff7a4755bed ("mm: Convert page_vma_mapped_walk to work on PFNs")
replaced page with pfns in page_vma_mapped_walk structure and updated
"@pvmw->page" to "@pvmw->pfn" in comment of function page_vma_mapped_walk.
This patch update stale "page" to "pfn" in comment of check_pte.
Link: https://lkml.kernel.org/r/20230707153953.1380615-1-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Fscache has an optimisation by which reads from the cache are skipped
until we know that (a) there's data there to be read and (b) that data
isn't entirely covered by pages resident in the netfs pagecache. This is
done with two flags manipulated by fscache_note_page_release():
if (...
test_bit(FSCACHE_COOKIE_HAVE_DATA, &cookie->flags) &&
test_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags))
clear_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags);
where the NO_DATA_TO_READ flag causes cachefiles_prepare_read() to
indicate that netfslib should download from the server or clear the page
instead.
The fscache_note_page_release() function is intended to be called from
->releasepage() - but that only gets called if PG_private or PG_private_2
is set - and currently the former is at the discretion of the network
filesystem and the latter is only set whilst a page is being written to
the cache, so sometimes we miss clearing the optimisation.
Fix this by following Willy's suggestion[1] and adding an address_space
flag, AS_RELEASE_ALWAYS, that causes filemap_release_folio() to always call
->release_folio() if it's set, even if PG_private or PG_private_2 aren't
set.
Note that this would require folio_test_private() and page_has_private() to
become more complicated. To avoid that, in the places[*] where these are
used to conditionalise calls to filemap_release_folio() and
try_to_release_page(), the tests are removed the those functions just
jumped to unconditionally and the test is performed there.
[*] There are some exceptions in vmscan.c where the check guards more than
just a call to the releaser. I've added a function, folio_needs_release()
to wrap all the checks for that.
AS_RELEASE_ALWAYS should be set if a non-NULL cookie is obtained from
fscache and cleared in ->evict_inode() before truncate_inode_pages_final()
is called.
Additionally, the FSCACHE_COOKIE_NO_DATA_TO_READ flag needs to be cleared
and the optimisation cancelled if a cachefiles object already contains data
when we open it.
[dwysocha@redhat.com: call folio_mapping() inside folio_needs_release()]
Link: https://github.com/DaveWysochanskiRH/kernel/commit/902c990e311120179fa5de99d68364b2947b79ec
Link: https://lkml.kernel.org/r/20230628104852.3391651-3-dhowells@redhat.com
Fixes: 1f67e6d0b188 ("fscache: Provide a function to note the release of a page")
Fixes: 047487c947e8 ("cachefiles: Implement the I/O routines")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Reported-by: Rohith Surabattula <rohiths.msft@gmail.com>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Tested-by: SeongJae Park <sj@kernel.org>
Cc: Daire Byrne <daire.byrne@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steve French <sfrench@samba.org>
Cc: Shyam Prasad N <nspmangalore@gmail.com>
Cc: Rohith Surabattula <rohiths.msft@gmail.com>
Cc: Dave Wysochanski <dwysocha@redhat.com>
Cc: Dominique Martinet <asmadeus@codewreck.org>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jingbo Xu <jefflexu@linux.alibaba.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm, netfs, fscache: Stop read optimisation when folio
removed from pagecache", v7.
This fixes an optimisation in fscache whereby we don't read from the cache
for a particular file until we know that there's data there that we don't
have in the pagecache. The problem is that I'm no longer using PG_fscache
(aka PG_private_2) to indicate that the page is cached and so I don't get
a notification when a cached page is dropped from the pagecache.
The first patch merges some folio_has_private() and
filemap_release_folio() pairs and introduces a helper,
folio_needs_release(), to indicate if a release is required.
The second patch is the actual fix. Following Willy's suggestions[1], it
adds an AS_RELEASE_ALWAYS flag to an address_space that will make
filemap_release_folio() always call ->release_folio(), even if
PG_private/PG_private_2 aren't set. folio_needs_release() is altered to
add a check for this.
This patch (of 2):
Make filemap_release_folio() check folio_has_private(). Then, in most
cases, where a call to folio_has_private() is immediately followed by a
call to filemap_release_folio(), we can get rid of the test in the pair.
There are a couple of sites in mm/vscan.c that this can't so easily be
done. In shrink_folio_list(), there are actually three cases (something
different is done for incompletely invalidated buffers), but
filemap_release_folio() elides two of them.
In shrink_active_list(), we don't have have the folio lock yet, so the
check allows us to avoid locking the page unnecessarily.
A wrapper function to check if a folio needs release is provided for those
places that still need to do it in the mm/ directory. This will acquire
additional parts to the condition in a future patch.
After this, the only remaining caller of folio_has_private() outside of
mm/ is a check in fuse.
Link: https://lkml.kernel.org/r/20230628104852.3391651-1-dhowells@redhat.com
Link: https://lkml.kernel.org/r/20230628104852.3391651-2-dhowells@redhat.com
Reported-by: Rohith Surabattula <rohiths.msft@gmail.com>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steve French <sfrench@samba.org>
Cc: Shyam Prasad N <nspmangalore@gmail.com>
Cc: Rohith Surabattula <rohiths.msft@gmail.com>
Cc: Dave Wysochanski <dwysocha@redhat.com>
Cc: Dominique Martinet <asmadeus@codewreck.org>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Xiubo Li <xiubli@redhat.com>
Cc: Jingbo Xu <jefflexu@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The lone caller already has the folio, so pass it in instead of deriving
it from the page again.
Link: https://lkml.kernel.org/r/20230706195251.2707542-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
CMA allocation can happen either from global cma or from dedicated cma
region.
Thus it is helpful to print cma name as well during initial
debugging to confirm cma regions were getting initialized or not.
Link: https://lkml.kernel.org/r/1688668414-12350-1-git-send-email-quic_pintu@quicinc.com
Signed-off-by: Pintu Kumar <quic_pintu@quicinc.com>
Signed-off-by: Pintu Agarwal <pintu.ping@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
It appears that destroy_memory_type() isn't a very good name because we
usually will not free the memory_type here. So rename it to a more
appropriate name i.e. put_memory_type().
Link: https://lkml.kernel.org/r/20230706063905.543800-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Suggested-by: Huang, Ying <ying.huang@intel.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Xiao Yang <yangx.jy@fujitsu.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "mm/memfd: fix sysctl MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED", v2.
When sysctl vm.memfd_noexec is 2 (MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED),
memfd_create(.., MFD_EXEC) should fail.
This complies with how MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED is defined -
"memfd_create() without MFD_NOEXEC_SEAL will be rejected"
Thanks to Dominique Martinet <asmadeus@codewreck.org> who reported the bug.
see [1] for context.
[1] https://lore.kernel.org/linux-mm/CABi2SkXUX_QqTQ10Yx9bBUGpN1wByOi_=gZU6WEy5a8MaQY3Jw@mail.gmail.com/T/
This patch (of 2):
When vm.memfd_noexec is 2 (MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED),
memfd_create(.., MFD_EXEC) should fail.
This complies with how MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED is
defined - "memfd_create() without MFD_NOEXEC_SEAL will be rejected"
Link: https://lkml.kernel.org/r/20230705063315.3680666-1-jeffxu@google.com
Link: https://lkml.kernel.org/r/20230705063315.3680666-2-jeffxu@google.com
Fixes: 105ff5339f49 ("mm/memfd: add MFD_NOEXEC_SEAL and MFD_EXEC")
Reported-by: Dominique Martinet <asmadeus@codewreck.org>
Closes: https://lore.kernel.org/linux-mm/CABi2SkXUX_QqTQ10Yx9bBUGpN1wByOi_=gZU6WEy5a8MaQY3Jw@mail.gmail.com/T/
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202306301351.kkbSegQW-lkp@intel.com/
Signed-off-by: Jeff Xu <jeffxu@google.com>
Cc: Daniel Verkamp <dverkamp@chromium.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jorge Lucangeli Obes <jorgelo@chromium.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
kmem.limit_in_bytes (v1 way to limit kernel memory usage) has been
deprecated since 58056f77502f ("memcg, kmem: further deprecate
kmem.limit_in_bytes") merged in 5.16. We haven't heard about any serious
users since then but it seems that the mere presence of the file is
causing more harm thatn good. We (SUSE) have had several bug reports from
customers where Docker based containers started to fail because a write to
kmem.limit_in_bytes has failed.
This was unexpected because runc code only expects ENOENT (kmem disabled)
or EBUSY (tasks already running within cgroup). So a new error code was
unexpected and the whole container startup failed. This has been later
addressed by
https://github.com/opencontainers/runc/commit/52390d68040637dfc77f9fda6bbe70952423d380
so current Docker runtimes do not suffer from the problem anymore. There
are still older version of Docker in use and likely hard to get rid of
completely.
Address this by wiping out the file completely and effectively get back to
pre 4.5 era and CONFIG_MEMCG_KMEM=n configuration.
I would recommend backporting to stable trees which have picked up
58056f77502f ("memcg, kmem: further deprecate kmem.limit_in_bytes").
[mhocko@suse.com: restore _KMEM switch case]
Link: https://lkml.kernel.org/r/ZKe5wxdbvPi5Cwd7@dhcp22.suse.cz
Link: https://lkml.kernel.org/r/20230704115240.14672-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
If pfn is outside zone boundaries in the first round, ret will be set to
1. But if pfn is changed to inside the zone boundaries in zone span
seqretry path, ret is still set to 1 leading to false page outside zone
error info.
This is from code inspection. The race window should be really small thus
hard to trigger in real world.
[akpm@linux-foundation.org: code simplification, per Matthew]
Link: https://lkml.kernel.org/r/20230704111823.940331-1-linmiaohe@huawei.com
Fixes: bdc8cb984576 ("[PATCH] memory hotplug locking: zone span seqlock")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
When use_zero_pages is enabled, the calculation of ksm profit is not
correct because ksm zero pages is not counted in. So update the
calculation of KSM profit including the documentation.
Link: https://lkml.kernel.org/r/20230613030942.186041-1-yang.yang29@zte.com.cn
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Xiaokai Ran <ran.xiaokai@zte.com.cn>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Cc: Jiang Xuexin <jiang.xuexin@zte.com.cn>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
As the number of ksm zero pages is not included in ksm_merging_pages per
process when enabling use_zero_pages, it's unclear of how many actual
pages are merged by KSM. To let users accurately estimate their memory
demands when unsharing KSM zero-pages, it's necessary to show KSM zero-
pages per process. In addition, it help users to know the actual KSM
profit because KSM-placed zero pages are also benefit from KSM.
since unsharing zero pages placed by KSM accurately is achieved, then
tracking empty pages merging and unmerging is not a difficult thing any
longer.
Since we already have /proc/<pid>/ksm_stat, just add the information of
'ksm_zero_pages' in it.
Link: https://lkml.kernel.org/r/20230613030938.185993-1-yang.yang29@zte.com.cn
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Xiaokai Ran <ran.xiaokai@zte.com.cn>
Reviewed-by: Yang Yang <yang.yang29@zte.com.cn>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Xuexin Jiang <jiang.xuexin@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
As pages_sharing and pages_shared don't include the number of zero pages
merged by KSM, we cannot know how many pages are zero pages placed by KSM
when enabling use_zero_pages, which leads to KSM not being transparent
with all actual merged pages by KSM. In the early days of use_zero_pages,
zero-pages was unable to get unshared by the ways like MADV_UNMERGEABLE so
it's hard to count how many times one of those zeropages was then
unmerged.
But now, unsharing KSM-placed zero page accurately has been achieved, so
we can easily count both how many times a page full of zeroes was merged
with zero-page and how many times one of those pages was then unmerged.
and so, it helps to estimate memory demands when each and every shared
page could get unshared.
So we add ksm_zero_pages under /sys/kernel/mm/ksm/ to show the number
of all zero pages placed by KSM. Meanwhile, we update the Documentation.
Link: https://lkml.kernel.org/r/20230613030934.185944-1-yang.yang29@zte.com.cn
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Xuexin Jiang <jiang.xuexin@zte.com.cn>
Reviewed-by: Xiaokai Ran <ran.xiaokai@zte.com.cn>
Reviewed-by: Yang Yang <yang.yang29@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "ksm: support tracking KSM-placed zero-pages", v10.
The core idea of this patch set is to enable users to perceive the number
of any pages merged by KSM, regardless of whether use_zero_page switch has
been turned on, so that users can know how much free memory increase is
really due to their madvise(MERGEABLE) actions. But the problem is, when
enabling use_zero_pages, all empty pages will be merged with kernel zero
pages instead of with each other as use_zero_pages is disabled, and then
these zero-pages are no longer monitored by KSM.
The motivations to do this is seen at:
https://lore.kernel.org/lkml/202302100915227721315@zte.com.cn/
In one word, we hope to implement the support for KSM-placed zero pages
tracking without affecting the feature of use_zero_pages, so that app
developer can also benefit from knowing the actual KSM profit by getting
KSM-placed zero pages to optimize applications eventually when
/sys/kernel/mm/ksm/use_zero_pages is enabled.
This patch (of 5):
When use_zero_pages of ksm is enabled, madvise(addr, len,
MADV_UNMERGEABLE) and other ways (like write 2 to /sys/kernel/mm/ksm/run)
to trigger unsharing will *not* actually unshare the shared zeropage as
placed by KSM (which is against the MADV_UNMERGEABLE documentation). As
these KSM-placed zero pages are out of the control of KSM, the related
counts of ksm pages don't expose how many zero pages are placed by KSM
(these special zero pages are different from those initially mapped zero
pages, because the zero pages mapped to MADV_UNMERGEABLE areas are
expected to be a complete and unshared page).
To not blindly unshare all shared zero_pages in applicable VMAs, the patch
use pte_mkdirty (related with architecture) to mark KSM-placed zero pages.
Thus, MADV_UNMERGEABLE will only unshare those KSM-placed zero pages.
In addition, we'll reuse this mechanism to reliably identify KSM-placed
ZeroPages to properly account for them (e.g., calculating the KSM profit
that includes zeropages) in the latter patches.
The patch will not degrade the performance of use_zero_pages as it doesn't
change the way of merging empty pages in use_zero_pages's feature.
Link: https://lkml.kernel.org/r/202306131104554703428@zte.com.cn
Link: https://lkml.kernel.org/r/20230613030928.185882-1-yang.yang29@zte.com.cn
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Xuexin Jiang <jiang.xuexin@zte.com.cn>
Reviewed-by: Xiaokai Ran <ran.xiaokai@zte.com.cn>
Reviewed-by: Yang Yang <yang.yang29@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Migrating file pages and swapcache pages into device memory is not
supported. Try to get rid of the swap cache, and if successful, go ahead
as with other anonymous pages.
Link: https://lkml.kernel.org/r/20230607172944.11713-1-mpenttil@redhat.com
Signed-off-by: Mika Penttilä <mpenttil@redhat.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
local_irq_save().
__build_all_zonelists() acquires zonelist_update_seq by first disabling
interrupts via local_irq_save() and then acquiring the seqlock with
write_seqlock(). This is troublesome and leads to problems on PREEMPT_RT.
The problem is that the inner spinlock_t becomes a sleeping lock on
PREEMPT_RT and must not be acquired with disabled interrupts.
The API provides write_seqlock_irqsave() which does the right thing in one
step. printk_deferred_enter() has to be invoked in non-migrate-able
context to ensure that deferred printing is enabled and disabled on the
same CPU. This is the case after zonelist_update_seq has been acquired.
There was discussion on the first submission that the order should be:
local_irq_disable();
printk_deferred_enter();
write_seqlock();
to avoid pitfalls like having an unaccounted printk() coming from
write_seqlock_irqsave() before printk_deferred_enter() is invoked. The
only origin of such a printk() can be a lockdep splat because the lockdep
annotation happens after the sequence count is incremented. This is
exceptional and subject to change.
It was also pointed that PREEMPT_RT can be affected by the printk problem
since its write_seqlock_irqsave() does not really disable interrupts.
This isn't the case because PREEMPT_RT's printk implementation differs
from the mainline implementation in two important aspects:
- Printing happens in a dedicated threads and not at during the
invocation of printk().
- In emergency cases where synchronous printing is used, a different
driver is used which does not use tty_port::lock.
Acquire zonelist_update_seq with write_seqlock_irqsave() and then defer
printk output.
Link: https://lkml.kernel.org/r/20230623201517.yw286Knb@linutronix.de
Fixes: 1007843a91909 ("mm/page_alloc: fix potential deadlock on zonelist_update_seq seqlock")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
__zs_compact always putback src_zspage into class list after
migrate_zspage. Thus, we don't need to keep last position of src_zspage
any more. Let's remove it.
Link: https://lkml.kernel.org/r/20230624053120.643409-4-senozhatsky@chromium.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Alexey Romanov <avromanov@sberdevices.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Destination zspage fullness check need to be done after zs_object_copy()
because that's where source and destination zspages fullness change.
Checking destination zspage fullness before zs_object_copy() may cause
migration to loop through source zspage sub-pages scanning for allocate
objects just to find out at the end that the destination zspage is full.
Link: https://lkml.kernel.org/r/20230624053120.643409-3-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Alexey Romanov <avromanov@sberdevices.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Patch series "zsmalloc: small compaction improvements", v2.
A tiny series that can reduce the number of find_alloced_obj() invocations
(which perform a linear scan of sub-page) during compaction. Inspired by
Alexey Romanov's findings.
This patch (of 3):
zspage migration can terminate as soon as it moves the last allocated
object from the source zspage. Add a simple helper zspage_empty() that
tests zspage ->inuse on each migration iteration.
Link: https://lkml.kernel.org/r/20230624053120.643409-2-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Suggested-by: Alexey Romanov <AVRomanov@sberdevices.ru>
Reviewed-by: Alexey Romanov <avromanov@sberdevices.ru>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
HASH_SMALL only works when parameter numentries is 0. But the sole caller
futex_init() never calls alloc_large_system_hash() with numentries set to
0. So HASH_SMALL is obsolete and remove it.
Link: https://lkml.kernel.org/r/20230625021323.849147-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: André Almeida <andrealmeid@igalia.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The current calculation of min_free_kbytes only uses ZONE_DMA and
ZONE_NORMAL pages,but the ZONE_MOVABLE zone->_watermark[WMARK_MIN] will
also divide part of min_free_kbytes.This will cause the min watermark of
ZONE_NORMAL to be too small in the presence of ZONE_MOVEABLE.
__GFP_HIGH and PF_MEMALLOC allocations usually don't need movable zone
pages, so just like ZONE_HIGHMEM, cap pages_min to a small value in
__setup_per_zone_wmarks().
On my testing machine with 16GB of memory (transparent hugepage is turned
off by default, and movablecore=12G is configured) The following is a
comparative test data of watermark_min
no patch add patch
ZONE_DMA 1 8
ZONE_DMA32 151 709
ZONE_NORMAL 233 1113
ZONE_MOVABLE 1434 128
min_free_kbytes 7288 7326
Link: https://lkml.kernel.org/r/20230625031656.23941-1-liuq131@chinatelecom.cn
Signed-off-by: liuq <liuq131@chinatelecom.cn>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Remove unneeded 'inline' annotation from num_poisoned_pages_inc() and
num_poisoned_pages_sub(). No functional change intended.
Link: https://lkml.kernel.org/r/20230626114343.1846587-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Use helper function destroy_memory_type() to release memtype instead of
open code it to help improve code readability a bit. No functional change
intended.
Link: https://lkml.kernel.org/r/20230626121053.1916447-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Wei Xu <weixugc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Remove unneeded PageLRU(p) and is_free_buddy_page(p) check as slab caches
are not shrunk now. This check can be added back when a lightweight range
based shrinker is available.
Link: https://lkml.kernel.org/r/20230628014929.3441386-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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ra->prev_pos tracks the last visited byte in the previous read request.
It is used to check whether it is sequential read in ondemand_readahead
and thus affects the readahead window.
After commit 06c0444290ce ("mm/filemap.c: generic_file_buffered_read() now
uses find_get_pages_contig"), update logic of prev_pos is changed. It
updates prev_pos after each return from filemap_get_pages(). But the read
request from user may be not fully completed at this point. The updated
prev_pos impacts the subsequent readahead window.
The real problem is performance drop of fsck_msdos between linux-5.4 and
linux-5.15(also linux-6.4). Comparing to linux-5.4,It spends about 110%
time and read 140% pages. The read pattern of fsck_msdos is not fully
sequential.
Simplified read pattern of fsck_msdos likes below:
1.read at page offset 0xa,size 0x1000
2.read at other page offset like 0x20,size 0x1000
3.read at page offset 0xa,size 0x4000
4.read at page offset 0xe,size 0x1000
Here is the read status on linux-6.4:
1.after read at page offset 0xa,size 0x1000
->page ofs 0xa go into pagecache
2.after read at page offset 0x20,size 0x1000
->page ofs 0x20 go into pagecache
3.read at page offset 0xa,size 0x4000
->filemap_get_pages read ofs 0xa from pagecache and returns
->prev_pos is updated to 0xb and goto next loop
->filemap_get_pages tends to read ofs 0xb,size 0x3000
->initial_readahead case in ondemand_readahead since prev_pos is
the same as request ofs.
->read 8 pages while async size is 5 pages
(PageReadahead flag at page 0xe)
4.read at page offset 0xe,size 0x1000
->hit page 0xe with PageReadahead flag set,double the ra_size.
read 16 pages while async size is 16 pages
Now it reads 24 pages while actually uses 5 pages
on linux-5.4:
1.the same as 6.4
2.the same as 6.4
3.read at page offset 0xa,size 0x4000
->read ofs 0xa from pagecache
->read ofs 0xb,size 0x3000 using page_cache_sync_readahead
read 3 pages
->prev_pos is updated to 0xd before generic_file_buffered_read
returns
4.read at page offset 0xe,size 0x1000
->initial_readahead case in ondemand_readahead since
request ofs-prev_pos==1
->read 4 pages while async size is 3 pages
Now it reads 7 pages while actually uses 5 pages.
In above demo, the initial_readahead case is triggered by offset of user
request on linux-5.4. While it may be triggered by update logic of
prev_pos on linux-6.4.
To fix the performance drop, update prev_pos after finishing one read
request.
Link: https://lkml.kernel.org/r/20230628110220.120134-1-haibo.li@mediatek.com
Signed-off-by: Haibo Li <haibo.li@mediatek.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Now __get_user_pages() should be well prepared to handle thp completely,
as long as hugetlb gup requests even without the hugetlb's special path.
Time to retire follow_hugetlb_page().
Tweak misc comments to reflect reality of follow_hugetlb_page()'s removal.
Link: https://lkml.kernel.org/r/20230628215310.73782-7-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A . Shutemov <kirill@shutemov.name>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The acceleration of THP was done with ctx.page_mask, however it'll be
ignored if **pages is non-NULL.
The old optimization was introduced in 2013 in 240aadeedc4a ("mm:
accelerate mm_populate() treatment of THP pages"). It didn't explain why
we can't optimize the **pages non-NULL case. It's possible that at that
time the major goal was for mm_populate() which should be enough back
then.
Optimize thp for all cases, by properly looping over each subpage, doing
cache flushes, and boost refcounts / pincounts where needed in one go.
This can be verified using gup_test below:
# chrt -f 1 ./gup_test -m 512 -t -L -n 1024 -r 10
Before: 13992.50 ( +-8.75%)
After: 378.50 (+-69.62%)
Link: https://lkml.kernel.org/r/20230628215310.73782-6-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A . Shutemov <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The only path that doesn't use generic "**pages" handling is the gate vma.
Make it use the same path, meanwhile tune the next_page label upper to
cover "**pages" handling. This prepares for THP handling for "**pages".
Link: https://lkml.kernel.org/r/20230628215310.73782-5-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A . Shutemov <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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follow_page() doesn't need it, but we'll start to need it when unifying
gup for hugetlb.
Link: https://lkml.kernel.org/r/20230628215310.73782-4-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A . Shutemov <kirill@shutemov.name>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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follow_page() doesn't use FOLL_PIN, meanwhile hugetlb seems to not be the
target of FOLL_WRITE either. However add the checks.
Namely, either the need to CoW due to missing write bit, or proper
unsharing on !AnonExclusive pages over R/O pins to reject the follow page.
That brings this function closer to follow_hugetlb_page().
So we don't care before, and also for now. But we'll care if we switch
over slow-gup to use hugetlb_follow_page_mask(). We'll also care when to
return -EMLINK properly, as that's the gup internal api to mean "we should
unshare". Not really needed for follow page path, though.
When at it, switching the try_grab_page() to use WARN_ON_ONCE(), to be
clear that it just should never fail. When error happens, instead of
setting page==NULL, capture the errno instead.
Link: https://lkml.kernel.org/r/20230628215310.73782-3-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A . Shutemov <kirill@shutemov.name>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series "mm/gup: Unify hugetlb, speed up thp", v4.
Hugetlb has a special path for slow gup that follow_page_mask() is
actually skipped completely along with faultin_page(). It's not only
confusing, but also duplicating a lot of logics that generic gup already
has, making hugetlb slightly special.
This patchset tries to dedup the logic, by first touching up the slow gup
code to be able to handle hugetlb pages correctly with the current follow
page and faultin routines (where we're mostly there.. due to 10 years ago
we did try to optimize thp, but half way done; more below), then at the
last patch drop the special path, then the hugetlb gup will always go the
generic routine too via faultin_page().
Note that hugetlb is still special for gup, mostly due to the pgtable
walking (hugetlb_walk()) that we rely on which is currently per-arch. But
this is still one small step forward, and the diffstat might be a proof
too that this might be worthwhile.
Then for the "speed up thp" side: as a side effect, when I'm looking at
the chunk of code, I found that thp support is actually partially done.
It doesn't mean that thp won't work for gup, but as long as **pages
pointer passed over, the optimization will be skipped too. Patch 6 should
address that, so for thp we now get full speed gup.
For a quick number, "chrt -f 1 ./gup_test -m 512 -t -L -n 1024 -r 10"
gives me 13992.50us -> 378.50us. Gup_test is an extreme case, but just to
show how it affects thp gups.
This patch (of 8):
Firstly, the no_page_table() is meaningless for hugetlb which is a no-op
there, because a hugetlb page always satisfies:
- vma_is_anonymous() == false
- vma->vm_ops->fault != NULL
So we can already safely remove it in hugetlb_follow_page_mask(), alongside
with the page* variable.
Meanwhile, what we do in follow_hugetlb_page() actually makes sense for a
dump: we try to fault in the page only if the page cache is already
allocated. Let's do the same here for follow_page_mask() on hugetlb.
It should so far has zero effect on real dumps, because that still goes
into follow_hugetlb_page(). But this may start to influence a bit on
follow_page() users who mimics a "dump page" scenario, but hopefully in a
good way. This also paves way for unifying the hugetlb gup-slow.
Link: https://lkml.kernel.org/r/20230628215310.73782-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20230628215310.73782-2-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A . Shutemov <kirill@shutemov.name>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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We would like to move away from requiring architectures to restore
metadata from swap in the set_pte_at() implementation, as this is not only
error-prone but adds complexity to the arch-specific code. This requires
us to call arch_swap_restore() before calling swap_free() whenever pages
are restored from swap. We are currently doing so everywhere except in
unuse_pte(); do so there as well.
Link: https://lkml.kernel.org/r/20230523004312.1807357-3-pcc@google.com
Link: https://linux-review.googlesource.com/id/I68276653e612d64cde271ce1b5a99ae05d6bbc4f
Signed-off-by: Peter Collingbourne <pcc@google.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: Chinwen Chang <chinwen.chang@mediatek.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: kasan-dev <kasan-dev@googlegroups.com>
Cc: "Kuan-Ying Lee (李冠穎)" <Kuan-Ying.Lee@mediatek.com>
Cc: Qun-Wei Lin <qun-wei.lin@mediatek.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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All callers of show_free_areas() pass 0 and NULL, so we can directly use
show_mem() instead of show_free_areas(0, NULL), which could make
show_free_areas() a static function.
Link: https://lkml.kernel.org/r/20230630062253.189440-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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