diff options
author | Enrik Berkhan <Enrik.Berkhan@ge.com> | 2009-03-13 13:51:56 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-03-14 11:57:22 -0700 |
commit | 020fe22ff14320927f394de222cbb11708bcc7a8 (patch) | |
tree | 1445c0134136c4aa84c9cb6aedd3043fae60f167 /mm/highmem.c | |
parent | 041b62374c7fedc11a8a1eeda2868612d3d1436c (diff) |
nommu: ramfs: pages allocated to an inode's pagecache may get wrongly discarded
The pages attached to a ramfs inode's pagecache by truncation from nothing
- as done by SYSV SHM for example - may get discarded under memory
pressure.
The problem is that the pages are not marked dirty. Anything that creates
data in an MMU-based ramfs will cause the pages holding that data will
cause the set_page_dirty() aop to be called.
For the NOMMU-based mmap, set_page_dirty() may be called by write(), but
it won't be called by page-writing faults on writable mmaps, and it isn't
called by ramfs_nommu_expand_for_mapping() when a file is being truncated
from nothing to allocate a contiguous run.
The solution is to mark the pages dirty at the point of allocation by the
truncation code.
Signed-off-by: Enrik Berkhan <Enrik.Berkhan@ge.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/highmem.c')
0 files changed, 0 insertions, 0 deletions