diff options
| author | NeilBrown <neilb@suse.de> | 2006-06-23 02:05:48 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-06-23 07:43:07 -0700 |
| commit | e0f23603fb2607315ce52432cc4225df410828cf (patch) | |
| tree | 7a32b42a64a64488aee0e91ab016d53c353f9482 /mm/truncate.c | |
| parent | 57ae2508610d50893cb3e3bbb869ff70ff724a2a (diff) | |
[PATCH] Remove semi-softlockup from invalidate_mapping_pages
If invalidate_mapping_pages is called to invalidate a very large mapping
(e.g. a very large block device) and if the only active page in that
device is near the end (or at least, at a very large index), such as, say,
the superblock of an md array, and if that page happens to be locked when
invalidate_mapping_pages is called, then
pagevec_lookup will return this page and
as it is locked, 'next' will be incremented and pagevec_lookup
will be called again. and again. and again.
while we count from 0 upto a very large number.
We should really always set 'next' to 'page->index+1' before going around
the loop again, not just if the page isn't locked.
Cc: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm/truncate.c')
| -rw-r--r-- | mm/truncate.c | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/mm/truncate.c b/mm/truncate.c index 6cb3fff25f67..cf1b015df4a7 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -230,14 +230,24 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping, pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { for (i = 0; i < pagevec_count(&pvec); i++) { struct page *page = pvec.pages[i]; + pgoff_t index; + int lock_failed; - if (TestSetPageLocked(page)) { - next++; - continue; - } - if (page->index > next) - next = page->index; + lock_failed = TestSetPageLocked(page); + + /* + * We really shouldn't be looking at the ->index of an + * unlocked page. But we're not allowed to lock these + * pages. So we rely upon nobody altering the ->index + * of this (pinned-by-us) page. + */ + index = page->index; + if (index > next) + next = index; next++; + if (lock_failed) + continue; + if (PageDirty(page) || PageWriteback(page)) goto unlock; if (page_mapped(page)) |