linux-toradex.git/include/linux/rmap.h, branch v4.13-rc4

mm: remove SWAP_[SUCCESS|AGAIN|FAIL]

2017-05-03T22:52:10+00:00

There is no user for it.  Remove it.

[minchan@kernel.org: use false instead of SWAP_FAIL]
  Link: http://lkml.kernel.org/r/20170316053313.GA19241@bbox
Link: http://lkml.kernel.org/r/1489555493-14659-11-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim 
Cc: Anshuman Khandual 
Cc: Hillf Danton 
Cc: Johannes Weiner 
Cc: Kirill A. Shutemov 
Cc: Michal Hocko 
Cc: Naoya Horiguchi 
Cc: Vlastimil Babka 
Cc: Sergey Senozhatsky 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: make rmap_one boolean function

2017-05-03T22:52:10+00:00

rmap_one's return value controls whether rmap_work should contine to
scan other ptes or not so it's target for changing to boolean.  Return
true if the scan should be continued.  Otherwise, return false to stop
the scanning.

This patch makes rmap_one's return value to boolean.

Link: http://lkml.kernel.org/r/1489555493-14659-10-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim 
Cc: Anshuman Khandual 
Cc: Hillf Danton 
Cc: Johannes Weiner 
Cc: Kirill A. Shutemov 
Cc: Michal Hocko 
Cc: Naoya Horiguchi 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: make rmap_walk() return void

2017-05-03T22:52:10+00:00

There is no user of the return value from rmap_walk() and friends so
this patch makes them void-returning functions.

Link: http://lkml.kernel.org/r/1489555493-14659-9-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim 
Cc: Anshuman Khandual 
Cc: Hillf Danton 
Cc: Johannes Weiner 
Cc: Kirill A. Shutemov 
Cc: Michal Hocko 
Cc: Naoya Horiguchi 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: make ttu's return boolean

2017-05-03T22:52:10+00:00

try_to_unmap() returns SWAP_SUCCESS or SWAP_FAIL so it's suitable for
boolean return.  This patch changes it.

Link: http://lkml.kernel.org/r/1489555493-14659-8-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim 
Cc: Naoya Horiguchi 
Cc: Anshuman Khandual 
Cc: Hillf Danton 
Cc: Johannes Weiner 
Cc: Kirill A. Shutemov 
Cc: Michal Hocko 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: remove SWAP_MLOCK in ttu

2017-05-03T22:52:10+00:00

ttu doesn't need to return SWAP_MLOCK.  Instead, just return SWAP_FAIL
because it means the page is not-swappable so it should move to another
LRU list(active or unevictable).  putback friends will move it to right
list depending on the page's LRU flag.

Link: http://lkml.kernel.org/r/1489555493-14659-6-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim 
Cc: Anshuman Khandual 
Cc: Hillf Danton 
Cc: Johannes Weiner 
Cc: Kirill A. Shutemov 
Cc: Michal Hocko 
Cc: Naoya Horiguchi 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: make try_to_munlock() return void

2017-05-03T22:52:10+00:00

try_to_munlock returns SWAP_MLOCK if the one of VMAs mapped the page has
VM_LOCKED flag.  In that time, VM set PG_mlocked to the page if the page
is not pte-mapped THP which cannot be mlocked, either.

With that, __munlock_isolated_page can use PageMlocked to check whether
try_to_munlock is successful or not without relying on try_to_munlock's
retval.  It helps to make try_to_unmap/try_to_unmap_one simple with
upcoming patches.

[minchan@kernel.org: remove PG_Mlocked VM_BUG_ON check]
  Link: http://lkml.kernel.org/r/20170411025615.GA6545@bbox
Link: http://lkml.kernel.org/r/1489555493-14659-5-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim 
Acked-by: Kirill A. Shutemov 
Acked-by: Vlastimil Babka 
Cc: Anshuman Khandual 
Cc: Hillf Danton 
Cc: Johannes Weiner 
Cc: Michal Hocko 
Cc: Naoya Horiguchi 
Cc: Sasha Levin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: remove SWAP_DIRTY in ttu

2017-05-03T22:52:10+00:00

If we found lazyfree page is dirty, try_to_unmap_one can just
SetPageSwapBakced in there like PG_mlocked page and just return with
SWAP_FAIL which is very natural because the page is not swappable right
now so that vmscan can activate it.  There is no point to introduce new
return value SWAP_DIRTY in try_to_unmap at the moment.

Link: http://lkml.kernel.org/r/1489555493-14659-3-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim 
Acked-by: Hillf Danton 
Acked-by: Kirill A. Shutemov 
Cc: Anshuman Khandual 
Cc: Johannes Weiner 
Cc: Michal Hocko 
Cc: Naoya Horiguchi 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: reclaim MADV_FREE pages

2017-05-03T22:52:08+00:00

When memory pressure is high, we free MADV_FREE pages.  If the pages are
not dirty in pte, the pages could be freed immediately.  Otherwise we
can't reclaim them.  We put the pages back to anonumous LRU list (by
setting SwapBacked flag) and the pages will be reclaimed in normal
swapout way.

We use normal page reclaim policy.  Since MADV_FREE pages are put into
inactive file list, such pages and inactive file pages are reclaimed
according to their age.  This is expected, because we don't want to
reclaim too many MADV_FREE pages before used once pages.

Based on Minchan's original patch

[minchan@kernel.org: clean up lazyfree page handling]
  Link: http://lkml.kernel.org/r/20170303025237.GB3503@bbox
Link: http://lkml.kernel.org/r/14b8eb1d3f6bf6cc492833f183ac8c304e560484.1487965799.git.shli@fb.com
Signed-off-by: Shaohua Li 
Signed-off-by: Minchan Kim 
Acked-by: Minchan Kim 
Acked-by: Michal Hocko 
Acked-by: Johannes Weiner 
Acked-by: Hillf Danton 
Cc: Hugh Dickins 
Cc: Rik van Riel 
Cc: Mel Gorman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: delete unnecessary TTU_* flags

2017-05-03T22:52:08+00:00

Patch series "mm: fix some MADV_FREE issues", v5.

We are trying to use MADV_FREE in jemalloc.  Several issues are found.
Without solving the issues, jemalloc can't use the MADV_FREE feature.

 - Doesn't support system without swap enabled. Because if swap is off,
   we can't or can't efficiently age anonymous pages. And since
   MADV_FREE pages are mixed with other anonymous pages, we can't
   reclaim MADV_FREE pages. In current implementation, MADV_FREE will
   fallback to MADV_DONTNEED without swap enabled. But in our
   environment, a lot of machines don't enable swap. This will prevent
   our setup using MADV_FREE.

 - Increases memory pressure. page reclaim bias file pages reclaim
   against anonymous pages. This doesn't make sense for MADV_FREE pages,
   because those pages could be freed easily and refilled with very
   slight penality. Even page reclaim doesn't bias file pages, there is
   still an issue, because MADV_FREE pages and other anonymous pages are
   mixed together. To reclaim a MADV_FREE page, we probably must scan a
   lot of other anonymous pages, which is inefficient. In our test, we
   usually see oom with MADV_FREE enabled and nothing without it.

 - Accounting. There are two accounting problems. We don't have a global
   accounting. If the system is abnormal, we don't know if it's a
   problem from MADV_FREE side. The other problem is RSS accounting.
   MADV_FREE pages are accounted as normal anon pages and reclaimed
   lazily, so application's RSS becomes bigger. This confuses our
   workloads. We have monitoring daemon running and if it finds
   applications' RSS becomes abnormal, the daemon will kill the
   applications even kernel can reclaim the memory easily.

To address the first the two issues, we can either put MADV_FREE pages
into a separate LRU list (Minchan's previous patches and V1 patches), or
put them into LRU_INACTIVE_FILE list (suggested by Johannes).  The
patchset use the second idea.  The reason is LRU_INACTIVE_FILE list is
tiny nowadays and should be full of used once file pages.  So we can
still efficiently reclaim MADV_FREE pages there without interference
with other anon and active file pages.  Putting the pages into inactive
file list also has an advantage which allows page reclaim to prioritize
MADV_FREE pages and used once file pages.  MADV_FREE pages are put into
the lru list and clear SwapBacked flag, so PageAnon(page) &&
!PageSwapBacked(page) will indicate a MADV_FREE pages.  These pages will
directly freed without pageout if they are clean, otherwise normal swap
will reclaim them.

For the third issue, the previous post adds global accounting and a
separate RSS count for MADV_FREE pages.  The problem is we never get
accurate accounting for MADV_FREE pages.  The pages are mapped to
userspace, can be dirtied without notice from kernel side.  To get
accurate accounting, we could write protect the page, but then there is
extra page fault overhead, which people don't want to pay.  Jemalloc
guys have concerns about the inaccurate accounting, so this post drops
the accounting patches temporarily.  The info exported to
/proc/pid/smaps for MADV_FREE pages are kept, which is the only place we
can get accurate accounting right now.

This patch (of 6):

Johannes pointed out TTU_LZFREE is unnecessary.  It's true because we
always have the flag set if we want to do an unmap.  For cases we don't
do an unmap, the TTU_LZFREE part of code should never run.

Also the TTU_UNMAP is unnecessary.  If no other flags set (for example,
TTU_MIGRATION), an unmap is implied.

The patch includes Johannes's cleanup and dead TTU_ACTION macro removal
code

Link: http://lkml.kernel.org/r/4be3ea1bc56b26fd98a54d0a6f70bec63f6d8980.1487965799.git.shli@fb.com
Signed-off-by: Shaohua Li 
Suggested-by: Johannes Weiner 
Acked-by: Johannes Weiner 
Acked-by: Minchan Kim 
Acked-by: Hillf Danton 
Acked-by: Michal Hocko 
Cc: Hugh Dickins 
Cc: Rik van Riel 
Cc: Mel Gorman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: drop page_check_address{,_transhuge}

2017-02-25T01:46:55+00:00

All users are gone. Let's drop them.

Link: http://lkml.kernel.org/r/20170129173858.45174-12-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov 
Cc: Andrea Arcangeli 
Cc: Hillf Danton 
Cc: Hugh Dickins 
Cc: Johannes Weiner 
Cc: Oleg Nesterov 
Cc: Peter Zijlstra 
Cc: Rik van Riel 
Cc: Srikar Dronamraju 
Cc: Vladimir Davydov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds