05 Mar, 2020
2 commits
-
commit f42f25526502d851d0e3ca1e46297da8aafce8a7 upstream.
If thp defrag setting "defer" is used and a newline is *not* used when
writing to the sysfs file, this is interpreted as the "defer+madvise"
option.This is because we do prefix matching and if five characters are written
without a newline, the current code ends up comparing to the first five
bytes of the "defer+madvise" option and using that instead.Use the more appropriate sysfs_streq() that handles the trailing newline
for us. Since this doubles as a nice cleanup, do it in enabled_store()
as well.The current implementation relies on prefix matching: the number of
bytes compared is either the number of bytes written or the length of
the option being compared. With a newline, "defer\n" does not match
"defer+"madvise"; without a newline, however, "defer" is considered to
match "defer+madvise" (prefix matching is only comparing the first five
bytes). End result is that writing "defer" is broken unless it has an
additional trailing character.This means that writing "madv" in the past would match and set
"madvise". With strict checking, that no longer is the case but it is
unlikely anybody is currently doing this.Link: http://lkml.kernel.org/r/alpine.DEB.2.21.2001171411020.56385@chino.kir.corp.google.com
Fixes: 21440d7eb904 ("mm, thp: add new defer+madvise defrag option")
Signed-off-by: David Rientjes
Suggested-by: Andrew Morton
Acked-by: Vlastimil Babka
Cc: Mel Gorman
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
Signed-off-by: Greg Kroah-Hartman -
commit cb829624867b5ab10bc6a7036d183b1b82bfe9f8 upstream.
The page could be a tail page, if this is the case, this BUG_ON will
never be triggered.Link: http://lkml.kernel.org/r/20200110032610.26499-1-richardw.yang@linux.intel.com
Fixes: e9b61f19858a ("thp: reintroduce split_huge_page()")Signed-off-by: Wei Yang
Acked-by: Kirill A. Shutemov
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
Signed-off-by: Greg Kroah-Hartman
23 Jan, 2020
1 commit
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commit 97d3d0f9a1cf132c63c0b8b8bd497b8a56283dd9 upstream.
Patch series "Fix two above-47bit hint address vs. THP bugs".
The two get_unmapped_area() implementations have to be fixed to provide
THP-friendly mappings if above-47bit hint address is specified.This patch (of 2):
Filesystems use thp_get_unmapped_area() to provide THP-friendly
mappings. For DAX in particular.Normally, the kernel doesn't create userspace mappings above 47-bit,
even if the machine allows this (such as with 5-level paging on x86-64).
Not all user space is ready to handle wide addresses. It's known that
at least some JIT compilers use higher bits in pointers to encode their
information.Userspace can ask for allocation from full address space by specifying
hint address (with or without MAP_FIXED) above 47-bits. If the
application doesn't need a particular address, but wants to allocate
from whole address space it can specify -1 as a hint address.Unfortunately, this trick breaks thp_get_unmapped_area(): the function
would not try to allocate PMD-aligned area if *any* hint address
specified.Modify the routine to handle it correctly:
- Try to allocate the space at the specified hint address with length
padding required for PMD alignment.
- If failed, retry without length padding (but with the same hint
address);
- If the returned address matches the hint address return it.
- Otherwise, align the address as required for THP and return.The user specified hint address is passed down to get_unmapped_area() so
above-47bit hint address will be taken into account without breaking
alignment requirements.Link: http://lkml.kernel.org/r/20191220142548.7118-2-kirill.shutemov@linux.intel.com
Fixes: b569bab78d8d ("x86/mm: Prepare to expose larger address space to userspace")
Signed-off-by: Kirill A. Shutemov
Reported-by: Thomas Willhalm
Tested-by: Dan Williams
Cc: "Aneesh Kumar K . V"
Cc: "Bruggeman, Otto G"
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
Signed-off-by: Greg Kroah-Hartman
19 Oct, 2019
1 commit
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Make sure split_huge_page_to_list() handles the state of shmem THP and
file THP properly.Link: http://lkml.kernel.org/r/20191017164223.2762148-3-songliubraving@fb.com
Fixes: 60fbf0ab5da1 ("mm,thp: stats for file backed THP")
Signed-off-by: Kirill A. Shutemov
Signed-off-by: Song Liu
Tested-by: Song Liu
Acked-by: Yang Shi
Cc: Matthew Wilcox (Oracle)
Cc: Oleg Nesterov
Cc: Srikar Dronamraju
Cc: William Kucharski
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
29 Sep, 2019
3 commits
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Merge hugepage allocation updates from David Rientjes:
"We (mostly Linus, Andrea, and myself) have been discussing offlist how
to implement a sane default allocation strategy for hugepages on NUMA
platforms.With these reverts in place, the page allocator will happily allocate
a remote hugepage immediately rather than try to make a local hugepage
available. This incurs a substantial performance degradation when
memory compaction would have otherwise made a local hugepage
available.This series reverts those reverts and attempts to propose a more sane
default allocation strategy specifically for hugepages. Andrea
acknowledges this is likely to fix the swap storms that he originally
reported that resulted in the patches that removed __GFP_THISNODE from
hugepage allocations.The immediate goal is to return 5.3 to the behavior the kernel has
implemented over the past several years so that remote hugepages are
not immediately allocated when local hugepages could have been made
available because the increased access latency is untenable.The next goal is to introduce a sane default allocation strategy for
hugepages allocations in general regardless of the configuration of
the system so that we prevent thrashing of local memory when
compaction is unlikely to succeed and can prefer remote hugepages over
remote native pages when the local node is low on memory."Note on timing: this reverts the hugepage VM behavior changes that got
introduced fairly late in the 5.3 cycle, and that fixed a huge
performance regression for certain loads that had been around since
4.18.Andrea had this note:
"The regression of 4.18 was that it was taking hours to start a VM
where 3.10 was only taking a few seconds, I reported all the details
on lkml when it was finally tracked down in August 2018.https://lore.kernel.org/linux-mm/20180820032640.9896-2-aarcange@redhat.com/
__GFP_THISNODE in MADV_HUGEPAGE made the above enterprise vfio
workload degrade like in the "current upstream" above. And it still
would have been that bad as above until 5.3-rc5"where the bad behavior ends up happening as you fill up a local node,
and without that change, you'd get into the nasty swap storm behavior
due to compaction working overtime to make room for more memory on the
nodes.As a result 5.3 got the two performance fix reverts in rc5.
However, David Rientjes then noted that those performance fixes in turn
regressed performance for other loads - although not quite to the same
degree. He suggested reverting the reverts and instead replacing them
with two small changes to how hugepage allocations are done (patch
descriptions rephrased by me):- "avoid expensive reclaim when compaction may not succeed": just admit
that the allocation failed when you're trying to allocate a huge-page
and compaction wasn't successful.- "allow hugepage fallback to remote nodes when madvised": when that
node-local huge-page allocation failed, retry without forcing the
local node.but by then I judged it too late to replace the fixes for a 5.3 release.
So 5.3 was released with behavior that harked back to the pre-4.18 logic.But now we're in the merge window for 5.4, and we can see if this
alternate model fixes not just the horrendous swap storm behavior, but
also restores the performance regression that the late reverts caused.Fingers crossed.
* emailed patches from David Rientjes :
mm, page_alloc: allow hugepage fallback to remote nodes when madvised
mm, page_alloc: avoid expensive reclaim when compaction may not succeed
Revert "Revert "Revert "mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask""
Revert "Revert "mm, thp: restore node-local hugepage allocations"" -
This reverts commit 92717d429b38e4f9f934eed7e605cc42858f1839.
Since commit a8282608c88e ("Revert "mm, thp: restore node-local hugepage
allocations"") is reverted in this series, it is better to restore the
previous 5.2 behavior between the thp allocation and the page allocator
rather than to attempt any consolidation or cleanup for a policy that is
now reverted. It's less risky during an rc cycle and subsequent patches
in this series further modify the same policy that the pre-5.3 behavior
implements.Consolidation and cleanup can be done subsequent to a sane default page
allocation strategy, so this patch reverts a cleanup done on a strategy
that is now reverted and thus is the least risky option.Signed-off-by: David Rientjes
Cc: Andrea Arcangeli
Cc: Michal Hocko
Cc: Mel Gorman
Cc: Vlastimil Babka
Cc: Stefan Priebe - Profihost AG
Cc: "Kirill A. Shutemov"
Cc: Andrew Morton
Signed-off-by: Linus Torvalds -
This reverts commit a8282608c88e08b1782141026eab61204c1e533f.
The commit references the original intended semantic for MADV_HUGEPAGE
which has subsequently taken on three unique purposes:- enables or disables thp for a range of memory depending on the system's
config (is thp "enabled" set to "always" or "madvise"),- determines the synchronous compaction behavior for thp allocations at
fault (is thp "defrag" set to "always", "defer+madvise", or "madvise"),
and- reverts a previous MADV_NOHUGEPAGE (there is no madvise mode to only
clear previous hugepage advice).These are the three purposes that currently exist in 5.2 and over the
past several years that userspace has been written around. Adding a
NUMA locality preference adds a fourth dimension to an already conflated
advice mode.Based on the semantic that MADV_HUGEPAGE has provided over the past
several years, there exist workloads that use the tunable based on these
principles: specifically that the allocation should attempt to
defragment a local node before falling back. It is agreed that remote
hugepages typically (but not always) have a better access latency than
remote native pages, although on Naples this is at parity for
intersocket.The revert commit that this patch reverts allows hugepage allocation to
immediately allocate remotely when local memory is fragmented. This is
contrary to the semantic of MADV_HUGEPAGE over the past several years:
that is, memory compaction should be attempted locally before falling
back.The performance degradation of remote hugepages over local hugepages on
Rome, for example, is 53.5% increased access latency. For this reason,
the goal is to revert back to the 5.2 and previous behavior that would
attempt local defragmentation before falling back. With the patch that
is reverted by this patch, we see performance degradations at the tail
because the allocator happily allocates the remote hugepage rather than
even attempting to make a local hugepage available.zone_reclaim_mode is not a solution to this problem since it does not
only impact hugepage allocations but rather changes the memory
allocation strategy for *all* page allocations.Signed-off-by: David Rientjes
Cc: Andrea Arcangeli
Cc: Michal Hocko
Cc: Mel Gorman
Cc: Vlastimil Babka
Cc: Stefan Priebe - Profihost AG
Cc: "Kirill A. Shutemov"
Cc: Andrew Morton
Signed-off-by: Linus Torvalds
25 Sep, 2019
3 commits
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Currently THP deferred split shrinker is not memcg aware, this may cause
premature OOM with some configuration. For example the below test would
run into premature OOM easily:$ cgcreate -g memory:thp
$ echo 4G > /sys/fs/cgroup/memory/thp/memory/limit_in_bytes
$ cgexec -g memory:thp transhuge-stress 4000transhuge-stress comes from kernel selftest.
It is easy to hit OOM, but there are still a lot THP on the deferred split
queue, memcg direct reclaim can't touch them since the deferred split
shrinker is not memcg aware.Convert deferred split shrinker memcg aware by introducing per memcg
deferred split queue. The THP should be on either per node or per memcg
deferred split queue if it belongs to a memcg. When the page is
immigrated to the other memcg, it will be immigrated to the target memcg's
deferred split queue too.Reuse the second tail page's deferred_list for per memcg list since the
same THP can't be on multiple deferred split queues.[yang.shi@linux.alibaba.com: simplify deferred split queue dereference per Kirill Tkhai]
Link: http://lkml.kernel.org/r/1566496227-84952-5-git-send-email-yang.shi@linux.alibaba.com
Link: http://lkml.kernel.org/r/1565144277-36240-5-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Yang Shi
Acked-by: Kirill A. Shutemov
Reviewed-by: Kirill Tkhai
Cc: Johannes Weiner
Cc: Michal Hocko
Cc: "Kirill A . Shutemov"
Cc: Hugh Dickins
Cc: Shakeel Butt
Cc: David Rientjes
Cc: Qian Cai
Cc: Vladimir Davydov
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Patch series "Make deferred split shrinker memcg aware", v6.
Currently THP deferred split shrinker is not memcg aware, this may cause
premature OOM with some configuration. For example the below test would
run into premature OOM easily:$ cgcreate -g memory:thp
$ echo 4G > /sys/fs/cgroup/memory/thp/memory/limit_in_bytes
$ cgexec -g memory:thp transhuge-stress 4000transhuge-stress comes from kernel selftest.
It is easy to hit OOM, but there are still a lot THP on the deferred split
queue, memcg direct reclaim can't touch them since the deferred split
shrinker is not memcg aware.Convert deferred split shrinker memcg aware by introducing per memcg
deferred split queue. The THP should be on either per node or per memcg
deferred split queue if it belongs to a memcg. When the page is
immigrated to the other memcg, it will be immigrated to the target memcg's
deferred split queue too.Reuse the second tail page's deferred_list for per memcg list since the
same THP can't be on multiple deferred split queues.Make deferred split shrinker not depend on memcg kmem since it is not
slab. It doesn't make sense to not shrink THP even though memcg kmem is
disabled.With the above change the test demonstrated above doesn't trigger OOM even
though with cgroup.memory=nokmem.This patch (of 4):
Put split_queue, split_queue_lock and split_queue_len into a struct in
order to reduce code duplication when we convert deferred_split to memcg
aware in the later patches.Link: http://lkml.kernel.org/r/1565144277-36240-2-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Yang Shi
Suggested-by: "Kirill A . Shutemov"
Acked-by: Kirill A. Shutemov
Reviewed-by: Kirill Tkhai
Cc: Johannes Weiner
Cc: Michal Hocko
Cc: Hugh Dickins
Cc: Shakeel Butt
Cc: David Rientjes
Cc: Qian Cai
Cc: Vladimir Davydov
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Transparent Huge Pages are currently stored in i_pages as pointers to
consecutive subpages. This patch changes that to storing consecutive
pointers to the head page in preparation for storing huge pages more
efficiently in i_pages.Large parts of this are "inspired" by Kirill's patch
https://lore.kernel.org/lkml/20170126115819.58875-2-kirill.shutemov@linux.intel.com/Kirill and Huang Ying contributed several fixes.
[willy@infradead.org: use compound_nr, squish uninit-var warning]
Link: http://lkml.kernel.org/r/20190731210400.7419-1-willy@infradead.org
Signed-off-by: Matthew Wilcox
Acked-by: Jan Kara
Reviewed-by: Kirill Shutemov
Reviewed-by: Song Liu
Tested-by: Song Liu
Tested-by: William Kucharski
Reviewed-by: William Kucharski
Tested-by: Qian Cai
Tested-by: Mikhail Gavrilov
Cc: Hugh Dickins
Cc: Chris Wilson
Cc: Song Liu
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
25 Aug, 2019
1 commit
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THP splitting path is missing the split_page_owner() call that
split_page() has.As a result, split THP pages are wrongly reported in the page_owner file
as order-9 pages. Furthermore when the former head page is freed, the
remaining former tail pages are not listed in the page_owner file at
all. This patch fixes that by adding the split_page_owner() call into
__split_huge_page().Link: http://lkml.kernel.org/r/20190820131828.22684-2-vbabka@suse.cz
Fixes: a9627bc5e34e ("mm/page_owner: introduce split_page_owner and replace manual handling")
Reported-by: Kirill A. Shutemov
Signed-off-by: Vlastimil Babka
Cc: Michal Hocko
Cc: Mel Gorman
Cc: Matthew Wilcox
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
14 Aug, 2019
2 commits
-
This reverts commit 2f0799a0ffc033b ("mm, thp: restore node-local
hugepage allocations").commit 2f0799a0ffc033b was rightfully applied to avoid the risk of a
severe regression that was reported by the kernel test robot at the end
of the merge window. Now we understood the regression was a false
positive and was caused by a significant increase in fairness during a
swap trashing benchmark. So it's safe to re-apply the fix and continue
improving the code from there. The benchmark that reported the
regression is very useful, but it provides a meaningful result only when
there is no significant alteration in fairness during the workload. The
removal of __GFP_THISNODE increased fairness.__GFP_THISNODE cannot be used in the generic page faults path for new
memory allocations under the MPOL_DEFAULT mempolicy, or the allocation
behavior significantly deviates from what the MPOL_DEFAULT semantics are
supposed to be for THP and 4k allocations alike.Setting THP defrag to "always" or using MADV_HUGEPAGE (with THP defrag
set to "madvise") has never meant to provide an implicit MPOL_BIND on
the "current" node the task is running on, causing swap storms and
providing a much more aggressive behavior than even zone_reclaim_node =
3.Any workload who could have benefited from __GFP_THISNODE has now to
enable zone_reclaim_mode=1||2||3. __GFP_THISNODE implicitly provided
the zone_reclaim_mode behavior, but it only did so if THP was enabled:
if THP was disabled, there would have been no chance to get any 4k page
from the current node if the current node was full of pagecache, which
further shows how this __GFP_THISNODE was misplaced in MADV_HUGEPAGE.
MADV_HUGEPAGE has never been intended to provide any zone_reclaim_mode
semantics, in fact the two are orthogonal, zone_reclaim_mode = 1|2|3
must work exactly the same with MADV_HUGEPAGE set or not.The performance characteristic of memory depends on the hardware
details. The numbers below are obtained on Naples/EPYC architecture and
the N/A projection extends them to show what we should aim for in the
future as a good THP NUMA locality default. The benchmark used
exercises random memory seeks (note: the cost of the page faults is not
part of the measurement).D0 THP | D0 4k | D1 THP | D1 4k | D2 THP | D2 4k | D3 THP | D3 4k | ...
0% | +43% | +45% | +106% | +131% | +224% | N/A | N/AD0 means distance zero (i.e. local memory), D1 means distance one (i.e.
intra socket memory), D2 means distance two (i.e. inter socket memory),
etc...For the guest physical memory allocated by qemu and for guest mode
kernel the performance characteristic of RAM is more complex and an
ideal default could be:D0 THP | D1 THP | D0 4k | D2 THP | D1 4k | D3 THP | D2 4k | D3 4k | ...
0% | +58% | +101% | N/A | +222% | N/A | N/A | N/ANOTE: the N/A are projections and haven't been measured yet, the
measurement in this case is done on a 1950x with only two NUMA nodes.
The THP case here means THP was used both in the host and in the guest.After applying this commit the THP NUMA locality order that we'll get
out of MADV_HUGEPAGE is this:D0 THP | D1 THP | D2 THP | D3 THP | ... | D0 4k | D1 4k | D2 4k | D3 4k | ...
Before this commit it was:
D0 THP | D0 4k | D1 4k | D2 4k | D3 4k | ...
Even if we ignore the breakage of large workloads that can't fit in a
single node that the __GFP_THISNODE implicit "current node" mbind
caused, the THP NUMA locality order provided by __GFP_THISNODE was still
not the one we shall aim for in the long term (i.e. the first one at
the top).After this commit is applied, we can introduce a new allocator multi
order API and to replace those two alloc_pages_vmas calls in the page
fault path, with a single multi order call:unsigned int order = (1 << HPAGE_PMD_ORDER) | (1 << 0);
page = alloc_pages_multi_order(..., &order);
if (!page)
goto out;
if (!(order & (1 << 0))) {
VM_WARN_ON(order != 1 << HPAGE_PMD_ORDER);
/* THP fault */
} else {
VM_WARN_ON(order != 1 << 0);
/* 4k fallback */
}The page allocator logic has to be altered so that when it fails on any
zone with order 9, it has to try again with a order 0 before falling
back to the next zone in the zonelist.After that we need to do more measurements and evaluate if adding an
opt-in feature for guest mode is worth it, to swap "DN 4k | DN+1 THP"
with "DN+1 THP | DN 4k" at every NUMA distance crossing.Link: http://lkml.kernel.org/r/20190503223146.2312-3-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli
Acked-by: Michal Hocko
Acked-by: Mel Gorman
Cc: Vlastimil Babka
Cc: David Rientjes
Cc: Zi Yan
Cc: Stefan Priebe - Profihost AG
Cc: "Kirill A. Shutemov"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Patch series "reapply: relax __GFP_THISNODE for MADV_HUGEPAGE mappings".
The fixes for what was originally reported as "pathological THP
behavior" we rightfully reverted to be sure not to introduced
regressions at end of a merge window after a severe regression report
from the kernel bot. We can safely re-apply them now that we had time
to analyze the problem.The mm process worked fine, because the good fixes were eventually
committed upstream without excessive delay.The regression reported by the kernel bot however forced us to revert
the good fixes to be sure not to introduce regressions and to give us
the time to analyze the issue further. The silver lining is that this
extra time allowed to think more at this issue and also plan for a
future direction to improve things further in terms of THP NUMA
locality.This patch (of 2):
This reverts commit 356ff8a9a78fb35d ("Revert "mm, thp: consolidate THP
gfp handling into alloc_hugepage_direct_gfpmask"). So it reapplies
89c83fb539f954 ("mm, thp: consolidate THP gfp handling into
alloc_hugepage_direct_gfpmask").Consolidation of the THP allocation flags at the same place was meant to
be a clean up to easier handle otherwise scattered code which is
imposing a maintenance burden. There were no real problems observed
with the gfp mask consolidation but the reversion was rushed through
without a larger consensus regardless.This patch brings the consolidation back because this should make the
long term maintainability easier as well as it should allow future
changes to be less error prone.[mhocko@kernel.org: changelog additions]
Link: http://lkml.kernel.org/r/20190503223146.2312-2-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli
Acked-by: Michal Hocko
Cc: Mel Gorman
Cc: Vlastimil Babka
Cc: David Rientjes
Cc: Zi Yan
Cc: Stefan Priebe - Profihost AG
Cc: "Kirill A. Shutemov"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
19 Jul, 2019
2 commits
-
Commit 7635d9cbe832 ("mm, thp, proc: report THP eligibility for each
vma") introduced THPeligible bit for processes' smaps. But, when
checking the eligibility for shmem vma, __transparent_hugepage_enabled()
is called to override the result from shmem_huge_enabled(). It may
result in the anonymous vma's THP flag override shmem's. For example,
running a simple test which create THP for shmem, but with anonymous THP
disabled, when reading the process's smaps, it may show:7fc92ec00000-7fc92f000000 rw-s 00000000 00:14 27764 /dev/shm/test
Size: 4096 kB
...
[snip]
...
ShmemPmdMapped: 4096 kB
...
[snip]
...
THPeligible: 0And, /proc/meminfo does show THP allocated and PMD mapped too:
ShmemHugePages: 4096 kB
ShmemPmdMapped: 4096 kBThis doesn't make too much sense. The shmem objects should be treated
separately from anonymous THP. Calling shmem_huge_enabled() with
checking MMF_DISABLE_THP sounds good enough. And, we could skip stack
and dax vma check since we already checked if the vma is shmem already.Also check if vma is suitable for THP by calling
transhuge_vma_suitable().And minor fix to smaps output format and documentation.
Link: http://lkml.kernel.org/r/1560401041-32207-3-git-send-email-yang.shi@linux.alibaba.com
Fixes: 7635d9cbe832 ("mm, thp, proc: report THP eligibility for each vma")
Signed-off-by: Yang Shi
Acked-by: Hugh Dickins
Cc: Kirill A. Shutemov
Cc: Michal Hocko
Cc: Vlastimil Babka
Cc: David Rientjes
Cc: Andrea Arcangeli
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
transhuge_vma_suitable() was only available for shmem THP, but anonymous
THP has the same check except pgoff check. And, it will be used for THP
eligible check in the later patch, so make it available for all kind of
THPs. This also helps reduce code duplication slightly.Since anonymous THP doesn't have to check pgoff, so make pgoff check
shmem vma only.And regroup some functions in include/linux/mm.h to solve compile issue
since transhuge_vma_suitable() needs call vma_is_anonymous() which was
defined after huge_mm.h is included.[akpm@linux-foundation.org: fix typo]
[yang.shi@linux.alibaba.com: v4]
Link: http://lkml.kernel.org/r/1563400758-124759-2-git-send-email-yang.shi@linux.alibaba.com
Link: http://lkml.kernel.org/r/1560401041-32207-2-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Yang Shi
Acked-by: Hugh Dickins
Cc: Kirill A. Shutemov
Cc: Michal Hocko
Cc: Vlastimil Babka
Cc: David Rientjes
Cc: Andrea Arcangeli
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
06 Jul, 2019
1 commit
-
This reverts commit 5fd4ca2d84b249f0858ce28cf637cf25b61a398f.
Mikhail Gavrilov reports that it causes the VM_BUG_ON_PAGE() in
__delete_from_swap_cache() to trigger:page:ffffd6d34dff0000 refcount:1 mapcount:1 mapping:ffff97812323a689 index:0xfecec363
anon
flags: 0x17fffe00080034(uptodate|lru|active|swapbacked)
raw: 0017fffe00080034 ffffd6d34c67c508 ffffd6d3504b8d48 ffff97812323a689
raw: 00000000fecec363 0000000000000000 0000000100000000 ffff978433ace000
page dumped because: VM_BUG_ON_PAGE(entry != page)
page->mem_cgroup:ffff978433ace000
------------[ cut here ]------------
kernel BUG at mm/swap_state.c:170!
invalid opcode: 0000 [#1] SMP NOPTI
CPU: 1 PID: 221 Comm: kswapd0 Not tainted 5.2.0-0.rc2.git0.1.fc31.x86_64 #1
Hardware name: System manufacturer System Product Name/ROG STRIX X470-I GAMING, BIOS 2202 04/11/2019
RIP: 0010:__delete_from_swap_cache+0x20d/0x240
Code: 30 65 48 33 04 25 28 00 00 00 75 4a 48 83 c4 38 5b 5d 41 5c 41 5d 41 5e 41 5f c3 48 c7 c6 2f dc 0f 8a 48 89 c7 e8 93 1b fd ff 0b 48 c7 c6 a8 74 0f 8a e8 85 1b fd ff 0f 0b 48 c7 c6 a8 7d 0f
RSP: 0018:ffffa982036e7980 EFLAGS: 00010046
RAX: 0000000000000021 RBX: 0000000000000040 RCX: 0000000000000006
RDX: 0000000000000000 RSI: 0000000000000086 RDI: ffff97843d657900
RBP: 0000000000000001 R08: ffffa982036e7835 R09: 0000000000000535
R10: ffff97845e21a46c R11: ffffa982036e7835 R12: ffff978426387120
R13: 0000000000000000 R14: ffffd6d34dff0040 R15: ffffd6d34dff0000
FS: 0000000000000000(0000) GS:ffff97843d640000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002cba88ef5000 CR3: 000000078a97c000 CR4: 00000000003406e0
Call Trace:
delete_from_swap_cache+0x46/0xa0
try_to_free_swap+0xbc/0x110
swap_writepage+0x13/0x70
pageout.isra.0+0x13c/0x350
shrink_page_list+0xc14/0xdf0
shrink_inactive_list+0x1e5/0x3c0
shrink_node_memcg+0x202/0x760
shrink_node+0xe0/0x470
balance_pgdat+0x2d1/0x510
kswapd+0x220/0x420
kthread+0xfb/0x130
ret_from_fork+0x22/0x40and it's not immediately obvious why it happens. It's too late in the
rc cycle to do anything but revert for now.Link: https://lore.kernel.org/lkml/CABXGCsN9mYmBD-4GaaeW_NrDu+FDXLzr_6x+XNxfmFV6QkYCDg@mail.gmail.com/
Reported-and-bisected-by: Mikhail Gavrilov
Suggested-by: Jan Kara
Cc: Michal Hocko
Cc: Vlastimil Babka
Cc: Matthew Wilcox
Cc: Kirill Shutemov
Cc: William Kucharski
Cc: Andrew Morton
Signed-off-by: Linus Torvalds
19 Jun, 2019
1 commit
-
Based on 1 normalized pattern(s):
this work is licensed under the terms of the gnu gpl version 2 see
the copying file in the top level directoryextracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 35 file(s).
Signed-off-by: Thomas Gleixner
Reviewed-by: Kate Stewart
Reviewed-by: Enrico Weigelt
Reviewed-by: Allison Randal
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.797835076@linutronix.de
Signed-off-by: Greg Kroah-Hartman
15 May, 2019
5 commits
-
__thp_get_unmapped_area is only used in mm/huge_memory.c. Make it static.
Tested by building and booting the kernel.Link: http://lkml.kernel.org/r/20190504102353.GA22525@bharath12345-Inspiron-5559
Signed-off-by: Bharath Vedartham
Acked-by: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This updates each existing invalidation to use the correct mmu notifier
event that represent what is happening to the CPU page table. See the
patch which introduced the events to see the rational behind this.Link: http://lkml.kernel.org/r/20190326164747.24405-7-jglisse@redhat.com
Signed-off-by: Jérôme Glisse
Reviewed-by: Ralph Campbell
Reviewed-by: Ira Weiny
Cc: Christian König
Cc: Joonas Lahtinen
Cc: Jani Nikula
Cc: Rodrigo Vivi
Cc: Jan Kara
Cc: Andrea Arcangeli
Cc: Peter Xu
Cc: Felix Kuehling
Cc: Jason Gunthorpe
Cc: Ross Zwisler
Cc: Dan Williams
Cc: Paolo Bonzini
Cc: Radim Krcmar
Cc: Michal Hocko
Cc: Christian Koenig
Cc: John Hubbard
Cc: Arnd Bergmann
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
CPU page table update can happens for many reasons, not only as a result
of a syscall (munmap(), mprotect(), mremap(), madvise(), ...) but also as
a result of kernel activities (memory compression, reclaim, migration,
...).Users of mmu notifier API track changes to the CPU page table and take
specific action for them. While current API only provide range of virtual
address affected by the change, not why the changes is happening.This patchset do the initial mechanical convertion of all the places that
calls mmu_notifier_range_init to also provide the default MMU_NOTIFY_UNMAP
event as well as the vma if it is know (most invalidation happens against
a given vma). Passing down the vma allows the users of mmu notifier to
inspect the new vma page protection.The MMU_NOTIFY_UNMAP is always the safe default as users of mmu notifier
should assume that every for the range is going away when that event
happens. A latter patch do convert mm call path to use a more appropriate
events for each call.This is done as 2 patches so that no call site is forgotten especialy
as it uses this following coccinelle patch:%vm_mm, E3, E4)
...>@@
expression E1, E2, E3, E4;
identifier FN, VMA;
@@
FN(..., struct vm_area_struct *VMA, ...) {
}@@
expression E1, E2, E3, E4;
identifier FN, VMA;
@@
FN(...) {
struct vm_area_struct *VMA;
}@@
expression E1, E2, E3, E4;
identifier FN;
@@
FN(...) {
}
---------------------------------------------------------------------->%Applied with:
spatch --all-includes --sp-file mmu-notifier.spatch fs/proc/task_mmu.c --in-place
spatch --sp-file mmu-notifier.spatch --dir kernel/events/ --in-place
spatch --sp-file mmu-notifier.spatch --dir mm --in-placeLink: http://lkml.kernel.org/r/20190326164747.24405-6-jglisse@redhat.com
Signed-off-by: Jérôme Glisse
Reviewed-by: Ralph Campbell
Reviewed-by: Ira Weiny
Cc: Christian König
Cc: Joonas Lahtinen
Cc: Jani Nikula
Cc: Rodrigo Vivi
Cc: Jan Kara
Cc: Andrea Arcangeli
Cc: Peter Xu
Cc: Felix Kuehling
Cc: Jason Gunthorpe
Cc: Ross Zwisler
Cc: Dan Williams
Cc: Paolo Bonzini
Cc: Radim Krcmar
Cc: Michal Hocko
Cc: Christian Koenig
Cc: John Hubbard
Cc: Arnd Bergmann
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Transparent Huge Pages are currently stored in i_pages as pointers to
consecutive subpages. This patch changes that to storing consecutive
pointers to the head page in preparation for storing huge pages more
efficiently in i_pages.Large parts of this are "inspired" by Kirill's patch
https://lore.kernel.org/lkml/20170126115819.58875-2-kirill.shutemov@linux.intel.com/[willy@infradead.org: fix swapcache pages]
Link: http://lkml.kernel.org/r/20190324155441.GF10344@bombadil.infradead.org
[kirill@shutemov.name: hugetlb stores pages in page cache differently]
Link: http://lkml.kernel.org/r/20190404134553.vuvhgmghlkiw2hgl@kshutemo-mobl1
Link: http://lkml.kernel.org/r/20190307153051.18815-1-willy@infradead.org
Signed-off-by: Matthew Wilcox
Acked-by: Jan Kara
Reviewed-by: Kirill Shutemov
Reviewed-and-tested-by: Song Liu
Tested-by: William Kucharski
Reviewed-by: William Kucharski
Tested-by: Qian Cai
Cc: Hugh Dickins
Cc: Song Liu
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Starting with c6f3c5ee40c1 ("mm/huge_memory.c: fix modifying of page
protection by insert_pfn_pmd()") vmf_insert_pfn_pmd() internally calls
pmdp_set_access_flags(). That helper enforces a pmd aligned @address
argument via VM_BUG_ON() assertion.Update the implementation to take a 'struct vm_fault' argument directly
and apply the address alignment fixup internally to fix crash signatures
like:kernel BUG at arch/x86/mm/pgtable.c:515!
invalid opcode: 0000 [#1] SMP NOPTI
CPU: 51 PID: 43713 Comm: java Tainted: G OE 4.19.35 #1
[..]
RIP: 0010:pmdp_set_access_flags+0x48/0x50
[..]
Call Trace:
vmf_insert_pfn_pmd+0x198/0x350
dax_iomap_fault+0xe82/0x1190
ext4_dax_huge_fault+0x103/0x1f0
? __switch_to_asm+0x40/0x70
__handle_mm_fault+0x3f6/0x1370
? __switch_to_asm+0x34/0x70
? __switch_to_asm+0x40/0x70
handle_mm_fault+0xda/0x200
__do_page_fault+0x249/0x4f0
do_page_fault+0x32/0x110
? page_fault+0x8/0x30
page_fault+0x1e/0x30Link: http://lkml.kernel.org/r/155741946350.372037.11148198430068238140.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: c6f3c5ee40c1 ("mm/huge_memory.c: fix modifying of page protection by insert_pfn_pmd()")
Signed-off-by: Dan Williams
Reported-by: Piotr Balcer
Tested-by: Yan Ma
Tested-by: Pankaj Gupta
Reviewed-by: Matthew Wilcox
Reviewed-by: Jan Kara
Reviewed-by: Aneesh Kumar K.V
Cc: Chandan Rajendra
Cc: Souptick Joarder
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
07 May, 2019
1 commit
-
Pull unified TLB flushing from Ingo Molnar:
"This contains the generic mmu_gather feature from Peter Zijlstra,
which is an all-arch unification of TLB flushing APIs, via the
following (broad) steps:- enhance the APIs to cover more arch details
- convert most TLB flushing arch implementations to the generic
APIs.- remove leftovers of per arch implementations
After this series every single architecture makes use of the unified
TLB flushing APIs"* 'core-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
mm/resource: Use resource_overlaps() to simplify region_intersects()
ia64/tlb: Eradicate tlb_migrate_finish() callback
asm-generic/tlb: Remove tlb_table_flush()
asm-generic/tlb: Remove tlb_flush_mmu_free()
asm-generic/tlb: Remove CONFIG_HAVE_GENERIC_MMU_GATHER
asm-generic/tlb: Remove arch_tlb*_mmu()
s390/tlb: Convert to generic mmu_gather
asm-generic/tlb: Introduce CONFIG_HAVE_MMU_GATHER_NO_GATHER=y
arch/tlb: Clean up simple architectures
um/tlb: Convert to generic mmu_gather
sh/tlb: Convert SH to generic mmu_gather
ia64/tlb: Convert to generic mmu_gather
arm/tlb: Convert to generic mmu_gather
asm-generic/tlb, arch: Invert CONFIG_HAVE_RCU_TABLE_INVALIDATE
asm-generic/tlb, ia64: Conditionally provide tlb_migrate_finish()
asm-generic/tlb: Provide generic tlb_flush() based on flush_tlb_mm()
asm-generic/tlb, arch: Provide generic tlb_flush() based on flush_tlb_range()
asm-generic/tlb, arch: Provide generic VIPT cache flush
asm-generic/tlb, arch: Provide CONFIG_HAVE_MMU_GATHER_PAGE_SIZE
asm-generic/tlb: Provide a comment
06 Apr, 2019
1 commit
-
With some architectures like ppc64, set_pmd_at() cannot cope with a
situation where there is already some (different) valid entry present.Use pmdp_set_access_flags() instead to modify the pfn which is built to
deal with modifying existing PMD entries.This is similar to commit cae85cb8add3 ("mm/memory.c: fix modifying of
page protection by insert_pfn()")We also do similar update w.r.t insert_pfn_pud eventhough ppc64 don't
support pud pfn entries now.Without this patch we also see the below message in kernel log "BUG:
non-zero pgtables_bytes on freeing mm:"Link: http://lkml.kernel.org/r/20190402115125.18803-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V
Reported-by: Chandan Rajendra
Reviewed-by: Jan Kara
Cc: Dan Williams
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
03 Apr, 2019
1 commit
-
Move the mmu_gather::page_size things into the generic code instead of
PowerPC specific bits.No change in behavior intended.
Signed-off-by: Peter Zijlstra (Intel)
Acked-by: Will Deacon
Cc: Andrew Morton
Cc: Andy Lutomirski
Cc: Aneesh Kumar K.V
Cc: Borislav Petkov
Cc: Dave Hansen
Cc: H. Peter Anvin
Cc: Linus Torvalds
Cc: Nick Piggin
Cc: Peter Zijlstra
Cc: Rik van Riel
Cc: Thomas Gleixner
Signed-off-by: Ingo Molnar
06 Mar, 2019
5 commits
-
Commit a00cc7d9dd93 ("mm, x86: add support for PUD-sized transparent
hugepages") introduced pudp_huge_get_and_clear_full() but no one uses
its return code.In order to not diverge from pmdp_huge_get_and_clear_full(), just change
zap_huge_pud() to not assign the return value from
pudp_huge_get_and_clear_full().mm/huge_memory.c: In function 'zap_huge_pud':
mm/huge_memory.c:1982:8: warning: variable 'orig_pud' set but not used [-Wunused-but-set-variable]
pud_t orig_pud;
^~~~~~~~Link: http://lkml.kernel.org/r/20190301221956.97493-1-cai@lca.pw
Signed-off-by: Qian Cai
Reviewed-by: Andrew Morton
Cc: Matthew Wilcox
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
We have common pattern to access lru_lock from a page pointer:
zone_lru_lock(page_zone(page))Which is silly, because it unfolds to this:
&NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)]->zone_pgdat->lru_lock
while we can simply do
&NODE_DATA(page_to_nid(page))->lru_lockRemove zone_lru_lock() function, since it's only complicate things. Use
'page_pgdat(page)->lru_lock' pattern instead.[aryabinin@virtuozzo.com: a slightly better version of __split_huge_page()]
Link: http://lkml.kernel.org/r/20190301121651.7741-1-aryabinin@virtuozzo.com
Link: http://lkml.kernel.org/r/20190228083329.31892-2-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin
Acked-by: Vlastimil Babka
Acked-by: Mel Gorman
Cc: Johannes Weiner
Cc: Michal Hocko
Cc: Rik van Riel
Cc: William Kucharski
Cc: John Hubbard
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Currently THP allocation events data is fairly opaque, since you can
only get it system-wide. This patch makes it easier to reason about
transparent hugepage behaviour on a per-memcg basis.For anonymous THP-backed pages, we already have MEMCG_RSS_HUGE in v1,
which is used for v1's rss_huge [sic]. This is reused here as it's
fairly involved to untangle NR_ANON_THPS right now to make it per-memcg,
since right now some of this is delegated to rmap before we have any
memcg actually assigned to the page. It's a good idea to rework that,
but let's leave untangling THP allocation for a future patch.[akpm@linux-foundation.org: fix build]
[chris@chrisdown.name: fix memcontrol build when THP is disabled]
Link: http://lkml.kernel.org/r/20190131160802.GA5777@chrisdown.name
Link: http://lkml.kernel.org/r/20190129205852.GA7310@chrisdown.name
Signed-off-by: Chris Down
Acked-by: Johannes Weiner
Cc: Tejun Heo
Cc: Roman Gushchin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
When calling debugfs functions, there is no need to ever check the
return value. The function can work or not, but the code logic should
never do something different based on this.Link: http://lkml.kernel.org/r/20190122152151.16139-14-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman
Cc: Michal Hocko
Cc: Vlastimil Babka
Cc: David Rientjes
Cc: Laura Abbott
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Patch series "Replace all open encodings for NUMA_NO_NODE", v3.
All these places for replacement were found by running the following
grep patterns on the entire kernel code. Please let me know if this
might have missed some instances. This might also have replaced some
false positives. I will appreciate suggestions, inputs and review.1. git grep "nid == -1"
2. git grep "node == -1"
3. git grep "nid = -1"
4. git grep "node = -1"This patch (of 2):
At present there are multiple places where invalid node number is
encoded as -1. Even though implicitly understood it is always better to
have macros in there. Replace these open encodings for an invalid node
number with the global macro NUMA_NO_NODE. This helps remove NUMA
related assumptions like 'invalid node' from various places redirecting
them to a common definition.Link: http://lkml.kernel.org/r/1545127933-10711-2-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual
Reviewed-by: David Hildenbrand
Acked-by: Jeff Kirsher [ixgbe]
Acked-by: Jens Axboe [mtip32xx]
Acked-by: Vinod Koul [dmaengine.c]
Acked-by: Michael Ellerman [powerpc]
Acked-by: Doug Ledford [drivers/infiniband]
Cc: Joseph Qi
Cc: Hans Verkuil
Cc: Stephen Rothwell
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
05 Jan, 2019
1 commit
-
Patch series "Add support for fast mremap".
This series speeds up the mremap(2) syscall by copying page tables at
the PMD level even for non-THP systems. There is concern that the extra
'address' argument that mremap passes to pte_alloc may do something
subtle architecture related in the future that may make the scheme not
work. Also we find that there is no point in passing the 'address' to
pte_alloc since its unused. This patch therefore removes this argument
tree-wide resulting in a nice negative diff as well. Also ensuring
along the way that the enabled architectures do not do anything funky
with the 'address' argument that goes unnoticed by the optimization.Build and boot tested on x86-64. Build tested on arm64. The config
enablement patch for arm64 will be posted in the future after more
testing.The changes were obtained by applying the following Coccinelle script.
(thanks Julia for answering all Coccinelle questions!).
Following fix ups were done manually:
* Removal of address argument from pte_fragment_alloc
* Removal of pte_alloc_one_fast definitions from m68k and microblaze.// Options: --include-headers --no-includes
// Note: I split the 'identifier fn' line, so if you are manually
// running it, please unsplit it so it runs for you.virtual patch
@pte_alloc_func_def depends on patch exists@
identifier E2;
identifier fn =~
"^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$";
type T2;
@@fn(...
- , T2 E2
)
{ ... }@pte_alloc_func_proto_noarg depends on patch exists@
type T1, T2, T3, T4;
identifier fn =~ "^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$";
@@(
- T3 fn(T1, T2);
+ T3 fn(T1);
|
- T3 fn(T1, T2, T4);
+ T3 fn(T1, T2);
)@pte_alloc_func_proto depends on patch exists@
identifier E1, E2, E4;
type T1, T2, T3, T4;
identifier fn =~
"^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$";
@@(
- T3 fn(T1 E1, T2 E2);
+ T3 fn(T1 E1);
|
- T3 fn(T1 E1, T2 E2, T4 E4);
+ T3 fn(T1 E1, T2 E2);
)@pte_alloc_func_call depends on patch exists@
expression E2;
identifier fn =~
"^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$";
@@fn(...
-, E2
)@pte_alloc_macro depends on patch exists@
identifier fn =~
"^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$";
identifier a, b, c;
expression e;
position p;
@@(
- #define fn(a, b, c) e
+ #define fn(a, b) e
|
- #define fn(a, b) e
+ #define fn(a) e
)Link: http://lkml.kernel.org/r/20181108181201.88826-2-joelaf@google.com
Signed-off-by: Joel Fernandes (Google)
Suggested-by: Kirill A. Shutemov
Acked-by: Kirill A. Shutemov
Cc: Michal Hocko
Cc: Julia Lawall
Cc: Kirill A. Shutemov
Cc: William Kucharski
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
29 Dec, 2018
4 commits
-
Userspace falls short when trying to find out whether a specific memory
range is eligible for THP. There are usecases that would like to know
that
http://lkml.kernel.org/r/alpine.DEB.2.21.1809251248450.50347@chino.kir.corp.google.com
: This is used to identify heap mappings that should be able to fault thp
: but do not, and they normally point to a low-on-memory or fragmentation
: issue.The only way to deduce this now is to query for hg resp. nh flags and
confronting the state with the global setting. Except that there is also
PR_SET_THP_DISABLE that might change the picture. So the final logic is
not trivial. Moreover the eligibility of the vma depends on the type of
VMA as well. In the past we have supported only anononymous memory VMAs
but things have changed and shmem based vmas are supported as well these
days and the query logic gets even more complicated because the
eligibility depends on the mount option and another global configuration
knob.Simplify the current state and report the THP eligibility in
/proc//smaps for each existing vma. Reuse
transparent_hugepage_enabled for this purpose. The original
implementation of this function assumes that the caller knows that the vma
itself is supported for THP so make the core checks into
__transparent_hugepage_enabled and use it for existing callers.
__show_smap just use the new transparent_hugepage_enabled which also
checks the vma support status (please note that this one has to be out of
line due to include dependency issues).[mhocko@kernel.org: fix oops with NULL ->f_mapping]
Link: http://lkml.kernel.org/r/20181224185106.GC16738@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/20181211143641.3503-3-mhocko@kernel.org
Signed-off-by: Michal Hocko
Acked-by: Vlastimil Babka
Cc: Dan Williams
Cc: David Rientjes
Cc: Jan Kara
Cc: Mike Rapoport
Cc: Paul Oppenheimer
Cc: William Kucharski
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
To avoid having to change many call sites everytime we want to add a
parameter use a structure to group all parameters for the mmu_notifier
invalidate_range_start/end cakks. No functional changes with this patch.[akpm@linux-foundation.org: coding style fixes]
Link: http://lkml.kernel.org/r/20181205053628.3210-3-jglisse@redhat.com
Signed-off-by: Jérôme Glisse
Acked-by: Christian König
Acked-by: Jan Kara
Cc: Matthew Wilcox
Cc: Ross Zwisler
Cc: Dan Williams
Cc: Paolo Bonzini
Cc: Radim Krcmar
Cc: Michal Hocko
Cc: Felix Kuehling
Cc: Ralph Campbell
Cc: John Hubbard
From: Jérôme Glisse
Subject: mm/mmu_notifier: use structure for invalidate_range_start/end calls v3fix build warning in migrate.c when CONFIG_MMU_NOTIFIER=n
Link: http://lkml.kernel.org/r/20181213171330.8489-3-jglisse@redhat.com
Signed-off-by: Jérôme Glisse
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Waiting on a page migration entry has used wait_on_page_locked() all along
since 2006: but you cannot safely wait_on_page_locked() without holding a
reference to the page, and that extra reference is enough to make
migrate_page_move_mapping() fail with -EAGAIN, when a racing task faults
on the entry before migrate_page_move_mapping() gets there.And that failure is retried nine times, amplifying the pain when trying to
migrate a popular page. With a single persistent faulter, migration
sometimes succeeds; with two or three concurrent faulters, success becomes
much less likely (and the more the page was mapped, the worse the overhead
of unmapping and remapping it on each try).This is especially a problem for memory offlining, where the outer level
retries forever (or until terminated from userspace), because a heavy
refault workload can trigger an endless loop of migration failures.
wait_on_page_locked() is the wrong tool for the job.David Herrmann (but was he the first?) noticed this issue in 2014:
https://marc.info/?l=linux-mm&m=140110465608116&w=2Tim Chen started a thread in August 2017 which appears relevant:
https://marc.info/?l=linux-mm&m=150275941014915&w=2 where Kan Liang went
on to implicate __migration_entry_wait():
https://marc.info/?l=linux-mm&m=150300268411980&w=2 and the thread ended
up with the v4.14 commits: 2554db916586 ("sched/wait: Break up long wake
list walk") 11a19c7b099f ("sched/wait: Introduce wakeup boomark in
wake_up_page_bit")Baoquan He reported "Memory hotplug softlock issue" 14 November 2018:
https://marc.info/?l=linux-mm&m=154217936431300&w=2We have all assumed that it is essential to hold a page reference while
waiting on a page lock: partly to guarantee that there is still a struct
page when MEMORY_HOTREMOVE is configured, but also to protect against
reuse of the struct page going to someone who then holds the page locked
indefinitely, when the waiter can reasonably expect timely unlocking.But in fact, so long as wait_on_page_bit_common() does the put_page(), and
is careful not to rely on struct page contents thereafter, there is no
need to hold a reference to the page while waiting on it. That does mean
that this case cannot go back through the loop: but that's fine for the
page migration case, and even if used more widely, is limited by the "Stop
walking if it's locked" optimization in wake_page_function().Add interface put_and_wait_on_page_locked() to do this, using "behavior"
enum in place of "lock" arg to wait_on_page_bit_common() to implement it.
No interruptible or killable variant needed yet, but they might follow: I
have a vague notion that reporting -EINTR should take precedence over
return from wait_on_page_bit_common() without knowing the page state, so
arrange it accordingly - but that may be nothing but pedantic.__migration_entry_wait() still has to take a brief reference to the page,
prior to calling put_and_wait_on_page_locked(): but now that it is dropped
before waiting, the chance of impeding page migration is very much
reduced. Should we perhaps disable preemption across this?shrink_page_list()'s __ClearPageLocked(): that was a surprise! This
survived a lot of testing before that showed up. PageWaiters may have
been set by wait_on_page_bit_common(), and the reference dropped, just
before shrink_page_list() succeeds in freezing its last page reference: in
such a case, unlock_page() must be used. Follow the suggestion from
Michal Hocko, just revert a978d6f52106 ("mm: unlockless reclaim") now:
that optimization predates PageWaiters, and won't buy much these days; but
we can reinstate it for the !PageWaiters case if anyone notices.It does raise the question: should vmscan.c's is_page_cache_freeable() and
__remove_mapping() now treat a PageWaiters page as if an extra reference
were held? Perhaps, but I don't think it matters much, since
shrink_page_list() already had to win its trylock_page(), so waiters are
not very common there: I noticed no difference when trying the bigger
change, and it's surely not needed while put_and_wait_on_page_locked() is
only used for page migration.[willy@infradead.org: add put_and_wait_on_page_locked() kerneldoc]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1811261121330.1116@eggly.anvils
Signed-off-by: Hugh Dickins
Reported-by: Baoquan He
Tested-by: Baoquan He
Reviewed-by: Andrea Arcangeli
Acked-by: Michal Hocko
Acked-by: Linus Torvalds
Acked-by: Vlastimil Babka
Cc: Matthew Wilcox
Cc: Baoquan He
Cc: David Hildenbrand
Cc: Mel Gorman
Cc: David Herrmann
Cc: Tim Chen
Cc: Kan Liang
Cc: Andi Kleen
Cc: Davidlohr Bueso
Cc: Peter Zijlstra
Cc: Christoph Lameter
Cc: Nick Piggin
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
totalram_pages and totalhigh_pages are made static inline function.
Main motivation was that managed_page_count_lock handling was complicating
things. It was discussed in length here,
https://lore.kernel.org/patchwork/patch/995739/#1181785 So it seemes
better to remove the lock and convert variables to atomic, with preventing
poteintial store-to-read tearing as a bonus.[akpm@linux-foundation.org: coding style fixes]
Link: http://lkml.kernel.org/r/1542090790-21750-4-git-send-email-arunks@codeaurora.org
Signed-off-by: Arun KS
Suggested-by: Michal Hocko
Suggested-by: Vlastimil Babka
Reviewed-by: Konstantin Khlebnikov
Reviewed-by: Pavel Tatashin
Acked-by: Michal Hocko
Acked-by: Vlastimil Babka
Cc: David Hildenbrand
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
22 Dec, 2018
1 commit
-
When splitting a huge migrating PMD, we'll transfer all the existing PMD
bits and apply them again onto the small PTEs. However we are fetching
the bits unconditionally via pmd_soft_dirty(), pmd_write() or
pmd_yound() while actually they don't make sense at all when it's a
migration entry. Fix them up. Since at it, drop the ifdef together as
not needed.Note that if my understanding is correct about the problem then if
without the patch there is chance to lose some of the dirty bits in the
migrating pmd pages (on x86_64 we're fetching bit 11 which is part of
swap offset instead of bit 2) and it could potentially corrupt the
memory of an userspace program which depends on the dirty bit.Link: http://lkml.kernel.org/r/20181213051510.20306-1-peterx@redhat.com
Signed-off-by: Peter Xu
Reviewed-by: Konstantin Khlebnikov
Reviewed-by: William Kucharski
Acked-by: Kirill A. Shutemov
Cc: Andrea Arcangeli
Cc: Matthew Wilcox
Cc: Michal Hocko
Cc: Dave Jiang
Cc: "Aneesh Kumar K.V"
Cc: Souptick Joarder
Cc: Konstantin Khlebnikov
Cc: Zi Yan
Cc: [4.14+]
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
09 Dec, 2018
1 commit
-
This reverts commit 89c83fb539f95491be80cdd5158e6f0ce329e317.
This should have been done as part of 2f0799a0ffc0 ("mm, thp: restore
node-local hugepage allocations"). The movement of the thp allocation
policy from alloc_pages_vma() to alloc_hugepage_direct_gfpmask() was
intended to only set __GFP_THISNODE for mempolicies that are not
MPOL_BIND whereas the revert could set this regardless of mempolicy.While the check for MPOL_BIND between alloc_hugepage_direct_gfpmask()
and alloc_pages_vma() was racy, that has since been removed since the
revert. What is left is the possibility to use __GFP_THISNODE in
policy_node() when it is unexpected because the special handling for
hugepages in alloc_pages_vma() was removed as part of the consolidation.Secondly, prior to 89c83fb539f9, alloc_pages_vma() implemented a somewhat
different policy for hugepage allocations, which were allocated through
alloc_hugepage_vma(). For hugepage allocations, if the allocating
process's node is in the set of allowed nodes, allocate with
__GFP_THISNODE for that node (for MPOL_PREFERRED, use that node with
__GFP_THISNODE instead). This was changed for shmem_alloc_hugepage() to
allow fallback to other nodes in 89c83fb539f9 as it did for new_page() in
mm/mempolicy.c which is functionally different behavior and removes the
requirement to only allocate hugepages locally.So this commit does a full revert of 89c83fb539f9 instead of the partial
revert that was done in 2f0799a0ffc0. The result is the same thp
allocation policy for 4.20 that was in 4.19.Fixes: 89c83fb539f9 ("mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask")
Fixes: 2f0799a0ffc0 ("mm, thp: restore node-local hugepage allocations")
Signed-off-by: David Rientjes
Acked-by: Vlastimil Babka
Cc: Andrea Arcangeli
Cc: Mel Gorman
Cc: Michal Hocko
Cc: Andrew Morton
Signed-off-by: Linus Torvalds
06 Dec, 2018
1 commit
-
This is a full revert of ac5b2c18911f ("mm: thp: relax __GFP_THISNODE for
MADV_HUGEPAGE mappings") and a partial revert of 89c83fb539f9 ("mm, thp:
consolidate THP gfp handling into alloc_hugepage_direct_gfpmask").By not setting __GFP_THISNODE, applications can allocate remote hugepages
when the local node is fragmented or low on memory when either the thp
defrag setting is "always" or the vma has been madvised with
MADV_HUGEPAGE.Remote access to hugepages often has much higher latency than local pages
of the native page size. On Haswell, ac5b2c18911f was shown to have a
13.9% access regression after this commit for binaries that remap their
text segment to be backed by transparent hugepages.The intent of ac5b2c18911f is to address an issue where a local node is
low on memory or fragmented such that a hugepage cannot be allocated. In
every scenario where this was described as a fix, there is abundant and
unfragmented remote memory available to allocate from, even with a greater
access latency.If remote memory is also low or fragmented, not setting __GFP_THISNODE was
also measured on Haswell to have a 40% regression in allocation latency.Restore __GFP_THISNODE for thp allocations.
Fixes: ac5b2c18911f ("mm: thp: relax __GFP_THISNODE for MADV_HUGEPAGE mappings")
Fixes: 89c83fb539f9 ("mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask")
Cc: Andrea Arcangeli
Cc: Mel Gorman
Cc: Vlastimil Babka
Cc: Michal Hocko
Cc: Andrew Morton
Signed-off-by: David Rientjes
Signed-off-by: Linus Torvalds
01 Dec, 2018
2 commits
-
Huge tmpfs testing, on 32-bit kernel with lockdep enabled, showed that
__split_huge_page() was using i_size_read() while holding the irq-safe
lru_lock and page tree lock, but the 32-bit i_size_read() uses an
irq-unsafe seqlock which should not be nested inside them.Instead, read the i_size earlier in split_huge_page_to_list(), and pass
the end offset down to __split_huge_page(): all while holding head page
lock, which is enough to prevent truncation of that extent before the
page tree lock has been taken.Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1811261520070.2275@eggly.anvils
Fixes: baa355fd33142 ("thp: file pages support for split_huge_page()")
Signed-off-by: Hugh Dickins
Acked-by: Kirill A. Shutemov
Cc: Jerome Glisse
Cc: Konstantin Khlebnikov
Cc: Matthew Wilcox
Cc: [4.8+]
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Huge tmpfs stress testing has occasionally hit shmem_undo_range()'s
VM_BUG_ON_PAGE(page_to_pgoff(page) != index, page).Move the setting of mapping and index up before the page_ref_unfreeze()
in __split_huge_page_tail() to fix this: so that a page cache lookup
cannot get a reference while the tail's mapping and index are unstable.In fact, might as well move them up before the smp_wmb(): I don't see an
actual need for that, but if I'm missing something, this way round is
safer than the other, and no less efficient.You might argue that VM_BUG_ON_PAGE(page_to_pgoff(page) != index, page) is
misplaced, and should be left until after the trylock_page(); but left as
is has not crashed since, and gives more stringent assurance.Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1811261516380.2275@eggly.anvils
Fixes: e9b61f19858a5 ("thp: reintroduce split_huge_page()")
Requires: 605ca5ede764 ("mm/huge_memory.c: reorder operations in __split_huge_page_tail()")
Signed-off-by: Hugh Dickins
Acked-by: Kirill A. Shutemov
Cc: Konstantin Khlebnikov
Cc: Jerome Glisse
Cc: Matthew Wilcox
Cc: [4.8+]
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds