linux.git/mm/rmap.c, branch v5.5

mm, thp: do not queue fully unmapped pages for deferred split

2019-12-01T20:59:09+00:00

Adding fully unmapped pages into deferred split queue is not productive:
these pages are about to be freed or they are pinned and cannot be split
anyway.

Link: http://lkml.kernel.org/r/20190913091849.11151-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov 
Reviewed-by: Yang Shi 
Cc: Michal Hocko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/rmap.c: use VM_BUG_ON_PAGE() in __page_check_anon_rmap()

2019-12-01T14:29:19+00:00

The __page_check_anon_rmap() just calls two BUG_ON()s protected by
CONFIG_DEBUG_VM, the #ifdef could be eliminated by using VM_BUG_ON_PAGE().

Link: http://lkml.kernel.org/r/1573157346-111316-1-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Yang Shi 
Acked-by: Kirill A. Shutemov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/rmap.c: fix outdated comment in page_get_anon_vma()

2019-12-01T14:29:19+00:00

Replace DESTROY_BY_RCU with SLAB_TYPESAFE_BY_RCU because
SLAB_DESTROY_BY_RCU has been renamed to SLAB_TYPESAFE_BY_RCU by commit
5f0d5a3ae7cf ("mm: Rename SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU")

Link: http://lkml.kernel.org/r/20191017093554.22562-1-miles.chen@mediatek.com
Signed-off-by: Miles Chen 
Cc: Paul E. McKenney 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/rmap.c: reuse mergeable anon_vma as parent when fork

2019-12-01T14:29:19+00:00

In __anon_vma_prepare(), we will try to find anon_vma if it is possible to
reuse it.  While on fork, the logic is different.

Since commit 5beb49305251 ("mm: change anon_vma linking to fix
multi-process server scalability issue"), function anon_vma_clone() tries
to allocate new anon_vma for child process.  But the logic here will
allocate a new anon_vma for each vma, even in parent this vma is mergeable
and share the same anon_vma with its sibling.  This may do better for
scalability issue, while it is not necessary to do so especially after
interval tree is used.

Commit 7a3ef208e662 ("mm: prevent endless growth of anon_vma hierarchy")
tries to reuse some anon_vma by counting child anon_vma and attached vmas.
While for those mergeable anon_vmas, we can just reuse it and not
necessary to go through the logic.

After this change, kernel build test reduces 20% anon_vma allocation.

Do the same kernel build test, it shows run time in sys reduced 11.6%.

Origin:

real    2m50.467s
user    17m52.002s
sys     1m51.953s

real    2m48.662s
user    17m55.464s
sys     1m50.553s

real    2m51.143s
user    17m59.687s
sys     1m53.600s

Patched:

real	2m39.933s
user	17m1.835s
sys	1m38.802s

real	2m39.321s
user	17m1.634s
sys	1m39.206s

real	2m39.575s
user	17m1.420s
sys	1m38.845s

Link: http://lkml.kernel.org/r/20191011072256.16275-2-richardw.yang@linux.intel.com
Signed-off-by: Wei Yang 
Acked-by: Konstantin Khlebnikov 
Cc: Kirill A. Shutemov 
Cc: "Jérôme Glisse" 
Cc: Mike Kravetz 
Cc: Rik van Riel 
Cc: Qian Cai 
Cc: Shakeel Butt 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/rmap.c: don't reuse anon_vma if we just want a copy

2019-12-01T14:29:19+00:00

Before commit 7a3ef208e662 ("mm: prevent endless growth of anon_vma
hierarchy"), anon_vma_clone() doesn't change dst->anon_vma.  While after
this commit, anon_vma_clone() will try to reuse an exist one on forking.

But this commit go a little bit further for the case not forking.
anon_vma_clone() is called from __vma_split(), __split_vma(), copy_vma()
and anon_vma_fork().  For the first three places, the purpose here is
get a copy of src and we don't expect to touch dst->anon_vma even it is
NULL.

While after that commit, it is possible to reuse an anon_vma when
dst->anon_vma is NULL.  This is not we intend to have.

This patch stops reuse of anon_vma for non-fork cases.

Link: http://lkml.kernel.org/r/20191011072256.16275-1-richardw.yang@linux.intel.com
Fixes: 7a3ef208e662 ("mm: prevent endless growth of anon_vma hierarchy")
Signed-off-by: Wei Yang 
Acked-by: Konstantin Khlebnikov 
Cc: Kirill A. Shutemov 
Cc: "Jérôme Glisse" 
Cc: Mike Kravetz 
Cc: Rik van Riel 
Cc: Qian Cai 
Cc: Shakeel Butt 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: include for is_vma_temporary_stack

2019-10-19T10:32:32+00:00

Include  for the definition of is_vma_temporary_stack
to fix the following sparse warning:

  mm/rmap.c:1673:6: warning: symbol 'is_vma_temporary_stack' was not declared. Should it be static?

Link: http://lkml.kernel.org/r/20191009151155.27763-1-ben.dooks@codethink.co.uk
Signed-off-by: Ben Dooks 
Reviewed-by: Qian Cai 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm,thp: add read-only THP support for (non-shmem) FS

2019-09-24T22:54:11+00:00

This patch is (hopefully) the first step to enable THP for non-shmem
filesystems.

This patch enables an application to put part of its text sections to THP
via madvise, for example:

    madvise((void *)0x600000, 0x200000, MADV_HUGEPAGE);

We tried to reuse the logic for THP on tmpfs.

Currently, write is not supported for non-shmem THP.  khugepaged will only
process vma with VM_DENYWRITE.  sys_mmap() ignores VM_DENYWRITE requests
(see ksys_mmap_pgoff).  The only way to create vma with VM_DENYWRITE is
execve().  This requirement limits non-shmem THP to text sections.

The next patch will handle writes, which would only happen when the all
the vmas with VM_DENYWRITE are unmapped.

An EXPERIMENTAL config, READ_ONLY_THP_FOR_FS, is added to gate this
feature.

[songliubraving@fb.com: fix build without CONFIG_SHMEM]
  Link: http://lkml.kernel.org/r/F53407FB-96CC-42E8-9862-105C92CC2B98@fb.com
[songliubraving@fb.com: fix double unlock in collapse_file()]
  Link: http://lkml.kernel.org/r/B960CBFA-8EFC-4DA4-ABC5-1977FFF2CA57@fb.com
Link: http://lkml.kernel.org/r/20190801184244.3169074-7-songliubraving@fb.com
Signed-off-by: Song Liu 
Acked-by: Rik van Riel 
Acked-by: Kirill A. Shutemov 
Acked-by: Johannes Weiner 
Cc: Stephen Rothwell 
Cc: Dan Carpenter 
Cc: Hillf Danton 
Cc: Hugh Dickins 
Cc: William Kucharski 
Cc: Oleg Nesterov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: introduce compound_nr()

2019-09-24T22:54:08+00:00

Replace 1 << compound_order(page) with compound_nr(page).  Minor
improvements in readability.

Link: http://lkml.kernel.org/r/20190721104612.19120-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) 
Reviewed-by: Andrew Morton 
Reviewed-by: Ira Weiny 
Acked-by: Kirill A. Shutemov 
Cc: Michal Hocko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: introduce page_size()

2019-09-24T22:54:08+00:00

Patch series "Make working with compound pages easier", v2.

These three patches add three helpers and convert the appropriate
places to use them.

This patch (of 3):

It's unnecessarily hard to find out the size of a potentially huge page.
Replace 'PAGE_SIZE << compound_order(page)' with page_size(page).

Link: http://lkml.kernel.org/r/20190721104612.19120-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) 
Acked-by: Michal Hocko 
Reviewed-by: Andrew Morton 
Reviewed-by: Ira Weiny 
Acked-by: Kirill A. Shutemov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/rmap.c: remove set but not used variable 'cstart'

2019-09-24T22:54:08+00:00

Fixes gcc '-Wunused-but-set-variable' warning:

mm/rmap.c: In function page_mkclean_one:
mm/rmap.c:906:17: warning: variable cstart set but not used [-Wunused-but-set-variable]

It is not used any more since
commit cdb07bdea28e ("mm/rmap.c: remove redundant variable cend")

Link: http://lkml.kernel.org/r/20190724141453.38536-1-yuehaibing@huawei.com
Signed-off-by: YueHaibing 
Reported-by: Hulk Robot 
Reviewed-by: Mike Kravetz 
Reviewed-by: Kirill Tkhai 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds