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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2011-07-24 10:47:59 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2011-07-24 10:48:00 +0200 |
| commit | 50a15981a1fac7e019ff7c3cba87531fb580f065 (patch) | |
| tree | 320ff80a5a01ae6936ac0a83cffb99e1f50adccf /mm | |
| parent | f433c4aec9999d1bf2ed8c328196f3b0ad5f75db (diff) | |
| download | kernel-common-50a15981a1fac7e019ff7c3cba87531fb580f065.tar.gz kernel-common-50a15981a1fac7e019ff7c3cba87531fb580f065.tar.bz2 kernel-common-50a15981a1fac7e019ff7c3cba87531fb580f065.zip | |
[S390] reference bit testing for unmapped pages
On x86 a page without a mapper is by definition not referenced / old.
The s390 architecture keeps the reference bit in the storage key and
the current code will check the storage key for page without a mapper.
This leads to an interesting effect: the first time an s390 system
needs to write pages to swap it only finds referenced pages. This
causes a lot of pages to get added and written to the swap device.
To avoid this behaviour change page_referenced to query the storage
key only if there is a mapper of the page.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/rmap.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/rmap.c b/mm/rmap.c index 2540a39eea4a..9701574bb67a 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -869,11 +869,11 @@ int page_referenced(struct page *page, vm_flags); if (we_locked) unlock_page(page); + + if (page_test_and_clear_young(page_to_pfn(page))) + referenced++; } out: - if (page_test_and_clear_young(page_to_pfn(page))) - referenced++; - return referenced; } |