Current call flow looks like this:
start_kernel
mm_core_init
mem_init
mem_init_print_info
rest_init
kernel_init
kernel_init_freeable
page_alloc_init_late
deferred_init_memmap
If CONFIG_DEFERRED_STRUCT_PAGE_INIT, the time mem_init_print_info()
calls, pages are not totally initialized and freed to buddy.
This has one issue
* nr_free_pages() just contains partial free pages in the system,
which is not we expect.
Let's print the mem info after defer_init is done.
Also this would help changing totalram_pages accounting, since we plan
to move the accounting into __free_pages_core().
Link: https://lkml.kernel.org/r/20240611145223.16872-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Setting 'limit' variable to 0 might seem like it means "no limit". But in
the memblock API, 0 actually means the 'MEMBLOCK_ALLOC_ACCESSIBLE' enum,
which limits the physical address range end based on
'memblock.current_limit'. This could be confusing.
Use the enum instead of 0 to make it clear.
Link: https://lkml.kernel.org/r/20240610151528.943680-1-lsahn@wewakecorp.com
Signed-off-by: Leesoo Ahn <lsahn@ooseel.net>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When the user no longer requires the pages, they would use
madvise(MADV_FREE) to mark the pages as lazy free. Subsequently, they
typically would not re-write to that memory again.
During memory reclaim, if we detect that the large folio and its PMD are
both still marked as clean and there are no unexpected references (such as
GUP), so we can just discard the memory lazily, improving the efficiency
of memory reclamation in this case.
On an Intel i5 CPU, reclaiming 1GiB of lazyfree THPs using
mem_cgroup_force_empty() results in the following runtimes in seconds
(shorter is better):
--------------------------------------------
| Old | New | Change |
--------------------------------------------
| 0.683426 | 0.049197 | -92.80% |
--------------------------------------------
[ioworker0@gmail.com: minor changes per David]
Link: https://lkml.kernel.org/r/20240622100057.3352-1-ioworker0@gmail.com
Link: https://lkml.kernel.org/r/20240614015138.31461-4-ioworker0@gmail.com
Signed-off-by: Lance Yang <ioworker0@gmail.com>
Suggested-by: Zi Yan <ziy@nvidia.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Cc: Bang Li <libang.li@antgroup.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Fangrui Song <maskray@google.com>
Cc: Jeff Xie <xiehuan09@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In preparation for supporting try_to_unmap_one() to unmap PMD-mapped
folios, start the pagewalk first, then call split_huge_pmd_address() to
split the folio.
Link: https://lkml.kernel.org/r/20240614015138.31461-3-ioworker0@gmail.com
Signed-off-by: Lance Yang <ioworker0@gmail.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Suggested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Cc: Bang Li <libang.li@antgroup.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Fangrui Song <maskray@google.com>
Cc: Jeff Xie <xiehuan09@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Reclaim lazyfree THP without splitting", v8.
This series adds support for reclaiming PMD-mapped THP marked as lazyfree
without needing to first split the large folio via
split_huge_pmd_address().
When the user no longer requires the pages, they would use
madvise(MADV_FREE) to mark the pages as lazy free. Subsequently, they
typically would not re-write to that memory again.
During memory reclaim, if we detect that the large folio and its PMD are
both still marked as clean and there are no unexpected references(such as
GUP), so we can just discard the memory lazily, improving the efficiency
of memory reclamation in this case.
Performance Testing
===================
On an Intel i5 CPU, reclaiming 1GiB of lazyfree THPs using
mem_cgroup_force_empty() results in the following runtimes in seconds
(shorter is better):
--------------------------------------------
| Old | New | Change |
--------------------------------------------
| 0.683426 | 0.049197 | -92.80% |
--------------------------------------------
This patch (of 8):
Introduce the labels walk_done and walk_abort as exit points to eliminate
duplicated exit code in the pagewalk loop.
Link: https://lkml.kernel.org/r/20240614015138.31461-1-ioworker0@gmail.com
Link: https://lkml.kernel.org/r/20240614015138.31461-2-ioworker0@gmail.com
Signed-off-by: Lance Yang <ioworker0@gmail.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Barry Song <baohua@kernel.org>
Cc: Bang Li <libang.li@antgroup.com>
Cc: Fangrui Song <maskray@google.com>
Cc: Jeff Xie <xiehuan09@gmail.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Most of the work done in folio_start_writeback is reversed in
folio_end_writeback. For e.g. NR_WRITEBACK and NR_ZONE_WRITE_PENDING are
incremented in start_writeback and decremented in end_writeback. Calling
end_writeback immediately after start_writeback (separated by
folio_unlock) cancels the affect of most of the work done in start hence
can be removed.
There is some extra work done in folio_end_writeback, however it is
incorrect/not applicable to zswap:
- folio_end_writeback incorrectly increments NR_WRITTEN counter,
eventhough the pages aren't written to disk, hence this change
corrects this behaviour.
- folio_end_writeback calls folio_rotate_reclaimable, but that only
makes sense for async writeback pages, while for zswap pages are
synchronously reclaimed.
Link: https://lkml.kernel.org/r/20240612100109.1616626-1-usamaarif642@gmail.com
Link: https://lkml.kernel.org/r/20240610143037.812955-1-usamaarif642@gmail.com
Signed-off-by: Usama Arif <usamaarif642@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>
Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
create_pagecache_thp_and_fd() in split_huge_page_test.c used the variable
dummy to perform mmap read.
However, this test was skipped even on XFS which has large folio support.
The issue was compiler (gcc 13.2.0) was optimizing out the dummy variable,
therefore, not creating huge page in the page cache.
Use asm volatile() trick to force the compiler not to optimize out the
loop where we read from the mmaped addr. This is similar to what is being
done in other tests (cow.c, etc)
As the variable is now used in the asm statement, remove the unused
attribute.
Link: https://lkml.kernel.org/r/20240606203619.677276-1-kernel@pankajraghav.com
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This patch leverages the new pte_needs_soft_dirty_wp() helper to optimize
a scenario where softdirty is enabled, but the softdirty flag has already
been set in do_swap_page(). In this situation, we can use pte_mkwrite
instead of applying write-protection since we don't depend on write
faults.
Link: https://lkml.kernel.org/r/20240607211358.4660-3-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm: introduce pmd|pte_needs_soft_dirty_wp helpers and
utilize them", v2.
This patchset introduces the pte_need_soft_dirty_wp and
pmd_need_soft_dirty_wp helpers to determine if write protection is
required for softdirty tracking. These helpers enhance code readability
and improve the overall appearance.
They are then utilized in gup, mprotect, swap, and other related
functions.
This patch (of 2):
This patch introduces the pte_needs_soft_dirty_wp and
pmd_needs_soft_dirty_wp helpers to determine if write protection is
required for softdirty tracking. This can enhance code readability and
improve its overall appearance. These new helpers are then utilized in
gup, huge_memory, and mprotect.
Link: https://lkml.kernel.org/r/20240607211358.4660-1-21cnbao@gmail.com
Link: https://lkml.kernel.org/r/20240607211358.4660-2-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
On Ubuntu 23.04, the kvm and mdwe selftests/mm build fails due to
missing a few items that are found in prctl.h. Here is an excerpt of the
build failures:
ksm_tests.c:252:13: error: use of undeclared identifier 'PR_SET_MEMORY_MERGE'
...
mdwe_test.c:26:18: error: use of undeclared identifier 'PR_SET_MDWE'
mdwe_test.c:38:18: error: use of undeclared identifier 'PR_GET_MDWE'
Fix these errors by adding a new tools/include/uapi/linux/prctl.h . This
file was created by running "make headers", and then copying a snapshot
over from ./usr/include/linux/prctl.h, as per the approach we settled on
in [1].
[1] commit e076eaca59 ("selftests: break the dependency upon local
header files")
Link: https://lkml.kernel.org/r/20240618022422.804305-6-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Andrei Vagin <avagin@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
On Ubuntu 23.04, on a clean git tree, the selftests/mm build fails due 10
or 20 missing items, all of which are found in fs.h, which is created via
"make headers". However, as per [1], the idea is to stop requiring "make
headers", and instead, take a snapshot of the files and check them in.
Here are a few of the build errors:
vm_util.c:34:21: error: variable has incomplete type 'struct pm_scan_arg'
struct pm_scan_arg arg;
...
vm_util.c:45:28: error: use of undeclared identifier 'PAGE_IS_WPALLOWED'
...
vm_util.c:55:21: error: variable has incomplete type 'struct page_region'
...
vm_util.c:105:20: error: use of undeclared identifier 'PAGE_IS_SOFT_DIRTY'
To fix this, add fs.h, taken from a snapshot of ./usr/include/linux/fs.h
after running "make headers".
[1] commit e076eaca59 ("selftests: break the dependency upon local
header files")
Link: https://lkml.kernel.org/r/20240618022422.804305-5-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Andrei Vagin <avagin@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Now that the test macros are factored out into their final location, and
simplified, it's time to rename TEST_END_CHECK to something that
represents its new functionality: REPORT_TEST_PASS.
Link: https://lkml.kernel.org/r/20240618022422.804305-4-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Jeff Xu <jeffxu@chromium.org>
Tested-by: Jeff Xu <jeffxu@chromium.org>
Cc: Andrei Vagin <avagin@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Clean up and move some copy-pasted items into a new mseal_helpers.h.
1. The test macros can be made safer and simpler, by observing that
they are invariably called when about to return. This means that the
macros do not need an intrusive label to goto; they can simply return.
2. PKEY* items. We cannot, unfortunately use pkey-helpers.h. The
best we can do is to factor out these few items into mseal_helpers.h.
3. These tests still need their own definition of u64, so also move
that to the header file.
4. Be sure to include the new mseal_helpers.h in the Makefile
dependencies.
[jhubbard@nvidia.com: include the new mseal_helpers.h in Makefile dependencies]
Link: https://lkml.kernel.org/r/01685978-f6b1-4c24-8397-22cd3c24b91a@nvidia.com
Link: https://lkml.kernel.org/r/20240618022422.804305-3-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Andrei Vagin <avagin@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "cleanups, fixes, and progress towards avoiding "make
headers"", v3.
Eventually, once the build succeeds on a sufficiently old distro, the idea
is to delete $(KHDR_INCLUDES) from the selftests/mm build, and then after
that, from selftests/lib.mk and all of the other selftest builds.
For now, this series merely achieves a clean build of selftests/mm on a
not-so-old distro: Ubuntu 23.04. In other words, after this series is
applied, it is possible to delete $(KHDR_INCLUDES) from
selftests/mm/Makefile and the build will still succeed.
1. Add tools/uapi/asm/unistd_[32|x32|64].h files, which include
definitions of __NR_mseal, and include them (indirectly) from the files
that use __NR_mseal. The new files are copied from ./usr/include/asm,
which is how we have agreed to do this sort of thing, see [1].
2. Add fs.h, similarly created: it was copied directly from a snapshot
of ./usr/include/linux/fs.h after running "make headers".
3. Add a few selected prctl.h values that the ksm and mdwe tests require.
4. Factor out some common code from mseal_test.c and seal_elf.c, into
a new mseal_helpers.h file.
5. Remove local __NR_* definitions and checks.
[1] commit e076eaca59 ("selftests: break the dependency upon local
header files")
This patch (of 6):
The selftests/mm build isn't exactly "broken", according to the current
documentation, which still claims that one must run "make headers",
before building the kselftests. However, according to the new plan to
get rid of that requirement [1], they are future-broken: attempting to
build selftests/mm *without* first running "make headers" will fail due
to not finding __NR_mseal.
Therefore, include asm-generic/unistd.h, which has all of the system
call numbers that are needed, abstracted across the various CPU arches.
Some explanation in support of this "asm-generic" approach:
For most user space programs, the header file inclusion behaves as per
this microblaze example, which comes from David Hildenbrand (thanks!):
arch/microblaze/include/asm/unistd.h
-> #include <uapi/asm/unistd.h>
arch/microblaze/include/uapi/asm/unistd.h
-> #include <asm/unistd_32.h>
-> Generated during "make headers"
usr/include/asm/unistd_32.h is generated via
arch/microblaze/kernel/syscalls/Makefile with the syshdr command.
So we never end up including asm-generic/unistd.h directly on
microblaze... [2]
However, those programs are installed on a single computer that has a
single set of asm and kernel headers installed.
In contrast, the kselftests are quite special, because they must
provide a set of user space programs that:
a) Mostly avoid using the installed (distro) system header files.
b) Build (and run) on all supported CPU architectures
c) Occasionally use symbols that have so new that they have not
yet been included in the distro's header files.
Doing (a) creates a new problem: how to get a set of cross-platform
headers that works in all cases.
Fortunately, asm-generic headers solve that one. Which is why we need
to use them here--at least, for particularly difficult headers such as
unistd.h.
The reason this hasn't really come up yet, is that until now, the
kselftests requirement (which I'm trying to eventually remove) was that
"make headers" must first be run. That allowed the selftests to get a
snapshot of sufficiently new header files that looked just like (and
conflict with) the installed system headers.
And as an aside, this is also an improvement over past practices of
simply open-coding in a single (not per-arch) definition of a new
symbol, directly into the selftest code.
[1] commit e076eaca59 ("selftests: break the dependency upon local
header files")
[2] https://lore.kernel.org/all/0b152bea-ccb6-403e-9c57-08ed5e828135@redhat.com/
Link: https://lkml.kernel.org/r/20240618022422.804305-1-jhubbard@nvidia.com
Link: https://lkml.kernel.org/r/20240618022422.804305-2-jhubbard@nvidia.com
Fixes: 4926c7a52d ("selftest mm/mseal memory sealing")
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Andrei Vagin <avagin@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit [1] introduced IO polling support duding swapin to reduce swap read
latency for block devices that can be polled. However later commit [2]
removed polling support. Commit [3] removed the remnants of polling
support from read_swap_cache_async() and __read_swap_cache_async().
However, it left behind some remnants in swap_read_folio(), the
'synchronous' argument.
swap_read_folio() reads the folio synchronously if synchronous=true or if
SWP_SYNCHRONOUS_IO is set in swap_info_struct. The only caller that
passes synchronous=true is in do_swap_page() in the SWP_SYNCHRONOUS_IO
case.
Hence, the argument is redundant, it is only set to true when the swap
read would have been synchronous anyway. Remove it.
[1] Commit 23955622ff ("swap: add block io poll in swapin path")
[2] Commit 9650b453a3 ("block: ignore RWF_HIPRI hint for sync dio")
[3] Commit b243dcbf2f ("swap: remove remnants of polling from read_swap_cache_async")
Link: https://lkml.kernel.org/r/20240607045515.1836558-1-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
It looks rather weird that totalhigh_pages() returns an "unsigned long"
but nr_free_highpages() returns an "unsigned int".
Let's return an "unsigned long" from nr_free_highpages() to be consistent.
While at it, use a plain "0" instead of a "0UL" in the !CONFIG_HIGHMEM
totalhigh_pages() implementation, to make these look alike as well.
Link: https://lkml.kernel.org/r/20240607083711.62833-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/highmem: don't track highmem pages manually".
Let's remove highmem special-casing from adjust_managed_page_count(), to
result in less confusion why memblock manually adjusts totalram_pages, and
__free_pages_core() only adjusts the zone's managed pages -- what about
the highmem pages that adjust_managed_page_count() updates?
Now, we only maintain totalram_pages and a zone's managed pages
independent of highmem support. We can derive the number of highmem pages
simply by looking at the relevant zone's managed pages. I don't think
there is any particular fast path that needs a maximum-efficient
totalhigh_pages() implementation.
Note that highmem memory is currently initialized using
free_highmem_page()->free_reserved_page(), not __free_pages_core(). In
the future we might want to also use __free_pages_core() to initialize
highmem memory, to make that less special, and consider moving
totalram_pages updates into __free_pages_core() [1], so we can just use
adjust_managed_page_count() in there as well.
Booting a simple kernel in QEMU reveals no highmem accounting change:
Before:
Memory: 3095448K/3145208K available (14802K kernel code, 2073K rwdata,
5000K rodata, 740K init, 556K bss, 49760K reserved, 0K cma-reserved,
2244488K highmem)
After:
Memory: 3095276K/3145208K available (14802K kernel code, 2073K rwdata,
5000K rodata, 740K init, 556K bss, 49932K reserved, 0K cma-reserved,
2244488K highmem)
[1] https://lkml.kernel.org/r/20240601133402.2675-1-richard.weiyang@gmail.com
This patch (of 2):
Can we get rid of the highmem ifdef in adjust_managed_page_count()?
Likely yes: we don't have that many totalhigh_pages() users, and they all
don't seem to be very performance critical.
So let's implement totalhigh_pages() like nr_free_highpages(), collecting
information from all zones. This is now similar to what we do in
si_meminfo_node() to collect the per-node highmem page count.
In the common case (single node, 3-4 zones), we really shouldn't care. We
could optimize a bit further (only walk ZONE_HIGHMEM and ZONE_MOVABLE if
required), but there doesn't seem a real need for that.
[david@redhat.com: fix build bot complaint]
Link: https://lkml.kernel.org/r/b57e5bc4-eb72-40e3-add4-57dfa6e03df6@redhat.com
Link: https://lkml.kernel.org/r/20240607083711.62833-1-david@redhat.com
Link: https://lkml.kernel.org/r/20240607083711.62833-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
That example was added in 2008. In 2015, we restricted access to the PFNs
in the pagemap to CAP_SYS_ADMIN, making that approach quite less usable.
It's 2024 now, and using that racy and low-lewel mechanism to calculate
the USS should not be considered a good example anymore. /proc/$pid/smaps
and /proc/$pid/smaps_rollup can do a much better job without any of that
low-level handling.
Let's just drop that example.
Link: https://lkml.kernel.org/r/20240607122357.115423-7-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Oscar Salvador <osalvador@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
... and rename it to folio_precise_page_mapcount(). fs/proc is the last
remaining user, and that should stay that way.
While at it, cleanup kpagecount_read() a bit: there are still some legacy
leftovers -- when the interface was introduced it returned the page
refcount, but was changed briefly afterwards to return the page mapcount.
Further, some simple folio conversion.
Once we stop using the per-page mapcounts of large folios, all
folio_precise_page_mapcount() users will have to implement an alternative
way to achieve what they are trying to achieve, possibly in a less precise
way.
[dan.carpenter@linaro.org: fix uninitialized variable in pagemap_pmd_range()]
Link: https://lkml.kernel.org/r/9d6eaba7-92f8-4a70-8765-38a519680a87@moroto.mountain
Link: https://lkml.kernel.org/r/20240607122357.115423-6-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Oscar Salvador <osalvador@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We currently rely on mapcount information for pages referenced by
non-present entries to calculate the USS (shared vs. private) and the
PSS.
However, relying on mapcounts for non-present entries doesn't make any
sense. We have to treat such entries as "maybe shared, but no idea how
often", implying that they will *not* get accounted towards the USS, and
will get fully accounted to the PSS (no idea how often shared).
There is one exception: device exclusive entries essentially behave like
present entries (e.g., mapcount incremented).
In smaps_pmd_entry(), use is_pfn_swap_entry() instead of
is_migration_entry(), which should not make a real difference but makes
the code look more similar to the PTE variant.
While at it, adjust the comments in smaps_account().
Link: https://lkml.kernel.org/r/20240607122357.115423-5-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Oscar Salvador <osalvador@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We added PM_MMAP_EXCLUSIVE in 2015 via commit 77bb499bb6 ("pagemap: add
mmap-exclusive bit for marking pages mapped only here"), when THPs could
not be partially mapped and page_mapcount() returned something that was
true for all pages of the THP.
In 2016, we added support for partially mapping THPs via commit
53f9263bab ("mm: rework mapcount accounting to enable 4k mapping of
THPs") but missed to determine PM_MMAP_EXCLUSIVE as well per page.
Checking page_mapcount() on the head page does not tell the whole story.
We should check each individual page. In a future without per-page
mapcounts it will be different, but we'll change that to be consistent
with PTE-mapped THPs once we deal with that.
Link: https://lkml.kernel.org/r/20240607122357.115423-4-david@redhat.com
Fixes: 53f9263bab ("mm: rework mapcount accounting to enable 4k mapping of THPs")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <ioworker0@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Relying on the mapcount for non-present PTEs that reference pages doesn't
make any sense: they are not accounted in the mapcount, so page_mapcount()
== 1 won't return the result we actually want to know.
While we don't check the mapcount for migration entries already, we could
end up checking it for swap, hwpoison, device exclusive, ... entries,
which we really shouldn't.
There is one exception: device private entries, which we consider
fake-present (e.g., incremented the mapcount). But we won't care about
that for now for PM_MMAP_EXCLUSIVE, because indicating PM_SWAP for them
although they are fake-present already sounds suspiciously wrong.
Let's never indicate PM_MMAP_EXCLUSIVE without PM_PRESENT.
Link: https://lkml.kernel.org/r/20240607122357.115423-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lance Yang <ioworker0@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "fs/proc: move page_mapcount() to fs/proc/internal.h".
With all other page_mapcount() users in the tree gone, move
page_mapcount() to fs/proc/internal.h, rename it and extend the
documentation to prevent future (ab)use.
... of course, I find some issues while working on that code that I sort
first ;)
We'll now only end up calling page_mapcount() [now
folio_precise_page_mapcount()] on pages mapped via present page table
entries. Except for /proc/kpagecount, that still does questionable
things, but we'll leave that legacy interface as is for now.
Did a quick sanity check. Likely we would want some better selfestest for
/proc/$/pagemap + smaps. I'll see if I can find some time to write some
more.
This patch (of 6):
Looks like we never taught pagemap_pmd_range() about the existence of
PMD-mapped file THPs. Seems to date back to the times when we first added
support for non-anon THPs in the form of shmem THP.
Link: https://lkml.kernel.org/r/20240607122357.115423-1-david@redhat.com
Link: https://lkml.kernel.org/r/20240607122357.115423-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Fixes: 800d8c63b2 ("shmem: add huge pages support")
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Lance Yang <ioworker0@gmail.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_hmm.o
Add the missing invocation of the MODULE_DESCRIPTION() macro.
Link: https://lkml.kernel.org/r/20240531-lib-md-test_hmm-v1-1-e4aa17daa57b@quicinc.com
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
make allmodconfig && make W=1 C=1 reports: WARNING: modpost: missing
MODULE_DESCRIPTION() in lib/test_maple_tree.o
Add the missing invocation of the MODULE_DESCRIPTION() macro.
Link: https://lkml.kernel.org/r/20240531-md-lib-test_maple_tree-v1-1-7b1b485aeec3@quicinc.com
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_ubsan.o
Add the missing invocation of the MODULE_DESCRIPTION() macro.
Link: https://lkml.kernel.org/r/20240531-md-lib-test_ubsan-v1-1-c2a80d258842@quicinc.com
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_xarray.o
Add the missing invocation of the MODULE_DESCRIPTION() macro.
Link: https://lkml.kernel.org/r/20240531-md-lib-test_xarray-v1-1-42fd6833bdd4@quicinc.com
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
After swapping out, we perform a swap-in operation. If we first read and
then write, we encounter a major fault in do_swap_page for reading, along
with additional minor faults in do_wp_page for writing. However, the
latter appears to be unnecessary and inefficient. Instead, we can
directly reuse in do_swap_page and completely eliminate the need for
do_wp_page.
This patch achieves that optimization specifically for exclusive folios.
The following microbenchmark demonstrates the significant reduction in
minor faults.
#define DATA_SIZE (2UL * 1024 * 1024)
#define PAGE_SIZE (4UL * 1024)
static void *read_write_data(char *addr)
{
char tmp;
for (int i = 0; i < DATA_SIZE; i += PAGE_SIZE) {
tmp = *(volatile char *)(addr + i);
*(volatile char *)(addr + i) = tmp;
}
}
int main(int argc, char **argv)
{
struct rusage ru;
char *addr = mmap(NULL, DATA_SIZE, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
memset(addr, 0x11, DATA_SIZE);
do {
long old_ru_minflt, old_ru_majflt;
long new_ru_minflt, new_ru_majflt;
madvise(addr, DATA_SIZE, MADV_PAGEOUT);
getrusage(RUSAGE_SELF, &ru);
old_ru_minflt = ru.ru_minflt;
old_ru_majflt = ru.ru_majflt;
read_write_data(addr);
getrusage(RUSAGE_SELF, &ru);
new_ru_minflt = ru.ru_minflt;
new_ru_majflt = ru.ru_majflt;
printf("minor faults:%ld major faults:%ld\n",
new_ru_minflt - old_ru_minflt,
new_ru_majflt - old_ru_majflt);
} while(0);
return 0;
}
w/o patch,
/ # ~/a.out
minor faults:512 major faults:512
w/ patch,
/ # ~/a.out
minor faults:0 major faults:512
Minor faults decrease to 0!
Link: https://lkml.kernel.org/r/20240602004502.26895-1-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The call for memblock_phys_free() in try_remove_memory() does not balance
any call to memblock_alloc() (or memblock_reserve() for that matter).
There are no memblock_reserve() calls in mm/memory_hotplug.c, no memblock
allocations possible after mm_core_init(), and even if memblock_add_node()
called from add_memory_resource() would need to allocate memory, that
memory would ba allocated from slab.
The patch f9126ab924 ("memory-hotplug: fix wrong edge when hot add a new
node") that introduced that call to memblock_free() does not provide
adequate description why that was required and tinkering with memblock in
the context of memory hotplug on x86 seems bogus because x86 never kept
memblock after boot anyway.
Drop memblock_phys_free() call in try_remove_memory().
[rppt@kernel.org: rewrite the commit message]
Link: https://lkml.kernel.org/r/20240605082049.973242-1-rppt@kernel.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in samples/kmemleak/kmemleak-test.o
Add the missing invocation of the MODULE_DESCRIPTION() macro.
Link: https://lkml.kernel.org/r/20240601-md-samples-kmemleak-v1-1-47186be7f0a8@quicinc.com
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add mTHP counters for anonymous shmem.
[baolin.wang@linux.alibaba.com: update Documentation/admin-guide/mm/transhuge.rst]
Link: https://lkml.kernel.org/r/d86e2e7f-4141-432b-b2ba-c6691f36ef0b@linux.alibaba.com
Link: https://lkml.kernel.org/r/4fd9e467d49ae4a747e428bcd821c7d13125ae67.1718090413.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Lance Yang <ioworker0@gmail.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Although the top-level hugepage allocation can be turned off, anonymous
shmem can still use mTHP by configuring the sysfs interface located at
'/sys/kernel/mm/transparent_hugepage/hugepage-XXkb/shmem_enabled'.
Therefore, add alignment for mTHP size to provide a suitable alignment
address in shmem_get_unmapped_area().
Link: https://lkml.kernel.org/r/0c549b57cf7db07503af692d8546ecfad0fcce52.1718090413.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Lance Yang <ioworker0@gmail.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit 19eaf44954 adds multi-size THP (mTHP) for anonymous pages, that
can allow THP to be configured through the sysfs interface located at
'/sys/kernel/mm/transparent_hugepage/hugepage-XXkb/enabled'.
However, the anonymous shmem will ignore the anonymous mTHP rule
configured through the sysfs interface, and can only use the PMD-mapped
THP, that is not reasonable. Users expect to apply the mTHP rule for all
anonymous pages, including the anonymous shmem, in order to enjoy the
benefits of mTHP. For example, lower latency than PMD-mapped THP, smaller
memory bloat than PMD-mapped THP, contiguous PTEs on ARM architecture to
reduce TLB miss etc. In addition, the mTHP interfaces can be extended to
support all shmem/tmpfs scenarios in the future, especially for the shmem
mmap() case.
The primary strategy is similar to supporting anonymous mTHP. Introduce a
new interface '/mm/transparent_hugepage/hugepage-XXkb/shmem_enabled',
which can have almost the same values as the top-level
'/sys/kernel/mm/transparent_hugepage/shmem_enabled', with adding a new
additional "inherit" option and dropping the testing options 'force' and
'deny'. By default all sizes will be set to "never" except PMD size,
which is set to "inherit". This ensures backward compatibility with the
anonymous shmem enabled of the top level, meanwhile also allows
independent control of anonymous shmem enabled for each mTHP.
Link: https://lkml.kernel.org/r/65796c1e72e51e15f3410195b5c2d5b6c160d411.1718090413.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
To support the use of mTHP with anonymous shmem, add a new sysfs interface
'shmem_enabled' in the '/sys/kernel/mm/transparent_hugepage/hugepages-kB/'
directory for each mTHP to control whether shmem is enabled for that mTHP,
with a value similar to the top level 'shmem_enabled', which can be set
to: "always", "inherit (to inherit the top level setting)", "within_size",
"advise", "never". An 'inherit' option is added to ensure compatibility
with these global settings, and the options 'force' and 'deny' are
dropped, which are rather testing artifacts from the old ages.
By default, PMD-sized hugepages have enabled="inherit" and all other
hugepage sizes have enabled="never" for
'/sys/kernel/mm/transparent_hugepage/hugepages-xxkB/shmem_enabled'.
In addition, if top level value is 'force', then only PMD-sized hugepages
have enabled="inherit", otherwise configuration will be failed and vice
versa. That means now we will avoid using non-PMD sized THP to override
the global huge allocation.
[baolin.wang@linux.alibaba.com: fix transhuge.rst indentation]
Link: https://lkml.kernel.org/r/b189d815-998b-4dfd-ba89-218ff51313f8@linux.alibaba.com
[akpm@linux-foundation.org: reflow transhuge.rst addition to 80 cols]
[baolin.wang@linux.alibaba.com: move huge_shmem_orders_lock under CONFIG_SYSFS]
Link: https://lkml.kernel.org/r/eb34da66-7f12-44f3-a39e-2bcc90c33354@linux.alibaba.com
[akpm@linux-foundation.org: huge_memory.c needs mm_types.h]
Link: https://lkml.kernel.org/r/ffddfa8b3cb4266ff963099ab78cfd7184c57ac7.1718090413.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In order to extend support for mTHP, add THP validation for PMD-mapped THP
related statistics to avoid statistical confusion.
Link: https://lkml.kernel.org/r/c4b04cbd51e6951cc2436a87be8eaa4a1516faec.1718090413.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Barry Song <v-songbaohua@oppo.com>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "add mTHP support for anonymous shmem", v5.
Anonymous pages have already been supported for multi-size (mTHP)
allocation through commit 19eaf44954, that can allow THP to be
configured through the sysfs interface located at
'/sys/kernel/mm/transparent_hugepage/hugepage-XXkb/enabled'.
However, the anonymous shmem will ignore the anonymous mTHP rule
configured through the sysfs interface, and can only use the PMD-mapped
THP, that is not reasonable. Many implement anonymous page sharing
through mmap(MAP_SHARED | MAP_ANONYMOUS), especially in database usage
scenarios, therefore, users expect to apply an unified mTHP strategy for
anonymous pages, also including the anonymous shared pages, in order to
enjoy the benefits of mTHP. For example, lower latency than PMD-mapped
THP, smaller memory bloat than PMD-mapped THP, contiguous PTEs on ARM
architecture to reduce TLB miss etc.
As discussed in the bi-weekly MM meeting[1], the mTHP controls should
control all of shmem, not only anonymous shmem, but support will be added
iteratively. Therefore, this patch set starts with support for anonymous
shmem.
The primary strategy is similar to supporting anonymous mTHP. Introduce a
new interface '/mm/transparent_hugepage/hugepage-XXkb/shmem_enabled',
which can have almost the same values as the top-level
'/sys/kernel/mm/transparent_hugepage/shmem_enabled', with adding a new
additional "inherit" option and dropping the testing options 'force' and
'deny'. By default all sizes will be set to "never" except PMD size,
which is set to "inherit". This ensures backward compatibility with the
anonymous shmem enabled of the top level, meanwhile also allows
independent control of anonymous shmem enabled for each mTHP.
Use the page fault latency tool to measure the performance of 1G anonymous shmem
with 32 threads on my machine environment with: ARM64 Architecture, 32 cores,
125G memory:
base: mm-unstable
user-time sys_time faults_per_sec_per_cpu faults_per_sec
0.04s 3.10s 83516.416 2669684.890
mm-unstable + patchset, anon shmem mTHP disabled
user-time sys_time faults_per_sec_per_cpu faults_per_sec
0.02s 3.14s 82936.359 2630746.027
mm-unstable + patchset, anon shmem 64K mTHP enabled
user-time sys_time faults_per_sec_per_cpu faults_per_sec
0.08s 0.31s 678630.231 17082522.495
From the data above, it is observed that the patchset has a minimal impact
when mTHP is not enabled (some fluctuations observed during testing).
When enabling 64K mTHP, there is a significant improvement of the page
fault latency.
[1] https://lore.kernel.org/all/f1783ff0-65bd-4b2b-8952-52b6822a0835@redhat.com/
This patch (of 6):
Add large folio mapping establishment support for finish_fault() as a
preparation, to support multi-size THP allocation of anonymous shmem pages
in the following patches.
Keep the same behavior (per-page fault) for non-anon shmem to avoid
inflating the RSS unintentionally, and we can discuss what size of mapping
to build when extending mTHP to control non-anon shmem in the future.
[baolin.wang@linux.alibaba.com: avoid going beyond the PMD pagetable size]
Link: https://lkml.kernel.org/r/b0e6a8b1-a32c-459e-ae67-fde5d28773e6@linux.alibaba.com
[baolin.wang@linux.alibaba.com: use 'PTRS_PER_PTE' instead of 'PTRS_PER_PTE - 1']
Link: https://lkml.kernel.org/r/e1f5767a-2c9b-4e37-afe6-1de26fe54e41@linux.alibaba.com
Link: https://lkml.kernel.org/r/cover.1718090413.git.baolin.wang@linux.alibaba.com
Link: https://lkml.kernel.org/r/3a190892355989d42f59cf9f2f98b94694b0d24d.1718090413.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Daniel Gomez <da.gomez@samsung.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Nobody checks the error flag any more, so setting it accomplishes nothing.
Remove the obsolete parts of this comment; it hasn't been true since
errseq_t was used to track writeback errors in 2017.
Link: https://lkml.kernel.org/r/20240531032938.2712870-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Replace PFNs with addresses in readahead window calculation. This
simplified the logic and reduce the code line number.
No functionality change is expected.
Link: https://lkml.kernel.org/r/20240531081230.310128-4-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When VMA based swap readahead is introduced in commit ec560175c0 ("mm,
swap: VMA based swap readahead"), "struct vma_swap_readahead" is defined
to describe the readahead window. Because we wanted to save the PTE
entries in the struct at that time. But after commit 4f8fcf4ced
("mm/swap: swap_vma_readahead() do the pte_offset_map()"), we no longer
save PTE entries in the struct. The size of the struct becomes so small,
that it's better to use the fields of the struct directly. This can
simplify the code to improve the code readability. The line number of
source code reduces too.
No functionality change is expected in this patch.
Link: https://lkml.kernel.org/r/20240531081230.310128-3-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm,swap: cleanup VMA based swap readahead window
calculation".
When VMA based swap readahead is introduced in commit ec560175c0 ("mm,
swap: VMA based swap readahead"), "struct vma_swap_readahead" is defined
to describe the readahead window. Because we wanted to save the PTE
entries in the struct at that time. But after commit 4f8fcf4ced
("mm/swap: swap_vma_readahead() do the pte_offset_map()"), we no longer
save PTE entries in the struct. The size of the struct becomes so small,
that it's better to use the fields of the struct directly. This can
simplify the code to improve the code readability. The line number of
source code reduces too.
A theoretical underflow issue and some related code cleanup is done in the
series too.
This patch (of 3):
In swap readahead window calculation, if the fault PFN is smaller than the
readahead window size, underflow may occurs. This is only possible in
theory, because the start of the virtual address space will not be used
for anonymous pages in practice. Even if underflow occurs, there will be
no functional bugs. In the worst cases, some swap entries may be swapped
in incorrectly and some pages may be allocate on the wrong nodes.
Anyway, we still needs to fix the issue via some underflow checking.
Link: https://lkml.kernel.org/r/20240531081230.310128-1-ying.huang@intel.com
Link: https://lkml.kernel.org/r/20240531081230.310128-2-ying.huang@intel.com
Fixes: ec560175c0 ("mm, swap: VMA based swap readahead")
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use existing swap() function rather than duplicating its implementation.
./mm/userfaultfd.c:1006:13-14: WARNING opportunity for swap()
Link: https://lkml.kernel.org/r/20240531091643.67778-1-jiapeng.chong@linux.alibaba.com
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=9266
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Consistently name the return variable with an _nr suffix, whenever calling
pfn_to_section_nr(), to avoid confusion with a (struct mem_section *).
Link: https://lkml.kernel.org/r/20240531124144.240399-1-dev.jain@arm.com
Signed-off-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In free_pagetable() we use the non-atomic version for clearing the
PageReserved bit from the page. free_pagetable() will either call
free_reserved_page() or put_page_bootmem(), which will eventually end up
calling free_reserved_page(), and in there we already clear the
PageReserved flag.
Link: https://lkml.kernel.org/r/20240527044523.29207-1-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
pxx_huge() has been removed in recent commit 9636f055da ("mm/treewide:
remove pXd_huge()"), however there are still three comments referencing
the API that got overlooked. Remove them.
Link: https://lkml.kernel.org/r/20240527154855.528816-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reported-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add a regression test to ensure that kmsan_unpoison_memory() works the
same as an unpoisoning operation added by the instrumentation.
The test has two subtests: one that checks the instrumentation, and one
that checks kmsan_unpoison_memory(). Each subtest initializes the first
byte of a 4-byte buffer, then checks that the other 3 bytes are
uninitialized.
[glider@google.com: change description, remove comment about failing test case]
Link: https://lkml.kernel.org/r/20240528104807.738758-2-glider@google.com
Signed-off-by: Brian Johannesmeyer <bjohannesmeyer@gmail.com>
Link: https://lore.kernel.org/lkml/20240524232804.1984355-1-bjohannesmeyer@gmail.com/T/
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kernel test robot reported [1] performance regression for will-it-scale
test suite's page_fault2 test case for the commit 70a64b7919 ("memcg:
dynamically allocate lruvec_stats"). After inspection it seems like the
commit has unintentionally introduced false cache sharing.
After the commit the fields of mem_cgroup_per_node which get read on the
performance critical path share the cacheline with the fields which get
updated often on LRU page allocations or deallocations. This has caused
contention on that cacheline and the workloads which manipulates a lot of
LRU pages are regressed as reported by the test report.
The solution is to rearrange the fields of mem_cgroup_per_node such that
the false sharing is eliminated. Let's move all the read only pointers at
the start of the struct, followed by memcg-v1 only fields and at the end
fields which get updated often.
Experiment setup: Ran fallocate1, fallocate2, page_fault1, page_fault2 and
page_fault3 from the will-it-scale test suite inside a three level memcg
with /tmp mounted as tmpfs on two different machines, one a single numa
node and the other one, two node machine.
$ ./[testcase]_processes -t $NR_CPUS -s 50
Results for single node, 52 CPU machine:
Testcase base with-patch
fallocate1 1031081 1431291 (38.80 %)
fallocate2 1029993 1421421 (38.00 %)
page_fault1 2269440 3405788 (50.07 %)
page_fault2 2375799 3572868 (50.30 %)
page_fault3 28641143 28673950 ( 0.11 %)
Results for dual node, 80 CPU machine:
Testcase base with-patch
fallocate1 2976288 3641185 (22.33 %)
fallocate2 2979366 3638181 (22.11 %)
page_fault1 6221790 7748245 (24.53 %)
page_fault2 6482854 7847698 (21.05 %)
page_fault3 28804324 28991870 ( 0.65 %)
Link: https://lkml.kernel.org/r/20240528164050.2625718-1-shakeel.butt@linux.dev
Fixes: 70a64b7919 ("memcg: dynamically allocate lruvec_stats")
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Reported-by: kernel test robot <oliver.sang@intel.com>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Feng Tang <feng.tang@intel.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
By using a folio in scan_movable_pages() we convert the last user of the
page-based hugetlb information macro functions to the folio version.
After this conversion, we can safely remove the page-based definitions
from include/linux/hugetlb.h.
Link: https://lkml.kernel.org/r/20240530171427.242018-1-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When a large folio is found in the swapcache, the current implementation
requires calling do_swap_page() nr_pages times, resulting in nr_pages page
faults. This patch opts to map the entire large folio at once to minimize
page faults. Additionally, redundant checks and early exits for ARM64 MTE
restoring are removed.
Link: https://lkml.kernel.org/r/20240529082824.150954-7-21cnbao@gmail.com
Signed-off-by: Chuanhua Han <hanchuanhua@oppo.com>
Co-developed-by: Barry Song <v-songbaohua@oppo.com>
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
