Commit 4917e5d0 authored by Johannes Weiner's avatar Johannes Weiner Committed by Linus Torvalds

mm: more likely reclaim MADV_SEQUENTIAL mappings

File pages mapped only in sequentially read mappings are perfect reclaim
canditates.

This patch makes these mappings behave like weak references, their pages
will be reclaimed unless they have a strong reference from a normal
mapping as well.

It changes the reclaim and the unmap path where they check if the page has
been referenced.  In both cases, accesses through sequentially read
mappings will be ignored.

Benchmark results from KOSAKI Motohiro:

    http://marc.info/?l=linux-mm&m=122485301925098&w=2Signed-off-by: default avatarJohannes Weiner <hannes@saeurebad.de>
Signed-off-by: default avatarRik van Riel <riel@redhat.com>
Acked-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 64cdd548
...@@ -767,7 +767,8 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, ...@@ -767,7 +767,8 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
else { else {
if (pte_dirty(ptent)) if (pte_dirty(ptent))
set_page_dirty(page); set_page_dirty(page);
if (pte_young(ptent)) if (pte_young(ptent) &&
likely(!VM_SequentialReadHint(vma)))
mark_page_accessed(page); mark_page_accessed(page);
file_rss--; file_rss--;
} }
......
...@@ -360,8 +360,17 @@ static int page_referenced_one(struct page *page, ...@@ -360,8 +360,17 @@ static int page_referenced_one(struct page *page,
goto out_unmap; goto out_unmap;
} }
if (ptep_clear_flush_young_notify(vma, address, pte)) if (ptep_clear_flush_young_notify(vma, address, pte)) {
/*
* Don't treat a reference through a sequentially read
* mapping as such. If the page has been used in
* another mapping, we will catch it; if this other
* mapping is already gone, the unmap path will have
* set PG_referenced or activated the page.
*/
if (likely(!VM_SequentialReadHint(vma)))
referenced++; referenced++;
}
/* Pretend the page is referenced if the task has the /* Pretend the page is referenced if the task has the
swap token and is in the middle of a page fault. */ swap token and is in the middle of a page fault. */
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment