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* [PATCH -mm 0/2] mm: page_ext: split page_ext flags
@ 2022-12-17 10:58 Yafang Shao
  2022-12-17 10:58 ` [PATCH -mm 1/2] mm: page_owner: split page_owner's flag from the comm flags Yafang Shao
                   ` (3 more replies)
  0 siblings, 4 replies; 11+ messages in thread
From: Yafang Shao @ 2022-12-17 10:58 UTC (permalink / raw)
  To: akpm; +Cc: vbabka, 42.hyeyoo, willy, linux-mm, Yafang Shao

On 64bit system, page extension is for debugging purpose only currently,
because of its overhead, in particular the memory overhead.

Once a page_ext is enabled, at least it will take 0.2% of the total
memory because of the page_ext flags, no matter this page_ext uses it or
not. Currently this page_ext flags is only used for page_owner on 64bit
system. So it doesn't make sense to allocate this flags for all page_ext
by default. We'd better move it into page_owner's structure, then when
someone wants to introduce a new page_ext which may be memory-overhead
sensitive, it will save this unneeded overhead.

On 32bit system, there's page_idle running on production envrionment,
which also uses this page_ext flags. So it will take another 0.2% of
total memory if the user enable both page_idle and page_owner after this
change, but considering page_owner is for debugging purpose only, the
memory overhead in this case won't be a problem.

So, let split the page_ext flags.

Yafang Shao (2):
  mm: page_owner: split page_owner's flag from the comm flags
  mm: page_idle: split 32bit page_idle's flag from the common flags

 include/linux/page_ext.h  | 14 +-------------
 include/linux/page_idle.h | 39 +++++++++++++++++++++++++++++++++------
 mm/page_ext.c             | 10 ----------
 mm/page_idle.c            | 12 ++++++++++++
 mm/page_owner.c           | 36 ++++++++++++++++++++++--------------
 5 files changed, 68 insertions(+), 43 deletions(-)

-- 
2.30.1 (Apple Git-130)



^ permalink raw reply	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2023-01-18  3:16 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-12-17 10:58 [PATCH -mm 0/2] mm: page_ext: split page_ext flags Yafang Shao
2022-12-17 10:58 ` [PATCH -mm 1/2] mm: page_owner: split page_owner's flag from the comm flags Yafang Shao
2022-12-17 10:58 ` [PATCH -mm 2/2] mm: page_idle: split 32bit page_idle's flag from the common flags Yafang Shao
2022-12-17 12:45   ` kernel test robot
2022-12-17 13:59     ` Yafang Shao
2022-12-17 12:45   ` kernel test robot
2022-12-18  8:08 ` [PATCH -mm 0/2] mm: page_ext: split page_ext flags Hyeonggon Yoo
2022-12-18 10:01   ` Yafang Shao
2022-12-18 11:22     ` Hyeonggon Yoo
2023-01-16 10:58 ` Vlastimil Babka
2023-01-18  3:15   ` Yafang Shao

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