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author | Zach Brown <zach.brown@oracle.com> | 2006-06-25 05:46:46 -0700 |
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committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-06-25 10:00:54 -0700 |
commit | 9f1a3cfcffaed2fbb3206179295c79ca8289f5c3 (patch) | |
tree | d7adeab100ff8e2fe0b64fa5b2c9ef09ec60c842 | |
parent | 09a9a45dc62fef5f46a0dc98a3cefdb464cc4aaa (diff) | |
download | lwn-9f1a3cfcffaed2fbb3206179295c79ca8289f5c3.tar.gz lwn-9f1a3cfcffaed2fbb3206179295c79ca8289f5c3.zip |
[PATCH] AOP_TRUNCATED_PAGE victims in read_pages() belong in the LRU
AOP_TRUNCATED_PAGE victims in read_pages() belong in the LRU
Nick Piggin rightly pointed out that the introduction of AOP_TRUNCATED_PAGE
to read_pages() was wrong to leave A_T_P victim pages in the page cache but
not put them in the LRU. Failing to do so hid them from the VM.
A_T_P just means that the aop method unlocked the page rather than
performing IO. It would be very rare that the page was truncated between
the unlock and testing A_T_P. So we leave the pages in the LRU for likely
reuse soon rather than backing them back out of the page cache. We do this
by matching the behaviour before the A_T_P introduction which added pages
to the LRU regardless of what ->readpage() did.
This doesn't include the unrelated cleanup in Nick's initial fix which
changed read_pages() to return void to match its only caller's behaviour of
ignoring errors.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Zach Brown <zach.brown@oracle.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r-- | mm/readahead.c | 13 |
1 files changed, 5 insertions, 8 deletions
diff --git a/mm/readahead.c b/mm/readahead.c index 0f142a40984b..4ee52cadab93 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -182,14 +182,11 @@ static int read_pages(struct address_space *mapping, struct file *filp, list_del(&page->lru); if (!add_to_page_cache(page, mapping, page->index, GFP_KERNEL)) { - ret = mapping->a_ops->readpage(filp, page); - if (ret != AOP_TRUNCATED_PAGE) { - if (!pagevec_add(&lru_pvec, page)) - __pagevec_lru_add(&lru_pvec); - continue; - } /* else fall through to release */ - } - page_cache_release(page); + mapping->a_ops->readpage(filp, page); + if (!pagevec_add(&lru_pvec, page)) + __pagevec_lru_add(&lru_pvec); + } else + page_cache_release(page); } pagevec_lru_add(&lru_pvec); ret = 0; |