diff options
| author |   Shaohua Li <shli@kernel.org> | 2012-10-08 16:32:19 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2012-10-09 16:22:47 +0900 |
| commit | 45cac65b0fcd287ebb877b141d40ba9bbe8e5da7 (patch) | |
| tree | 30ed25c91aaeed153de51a78d171cb14582e383f /include | |
| parent | atomic: implement generic atomic_dec_if_positive() (diff) | |
| download | linux-dev-45cac65b0fcd287ebb877b141d40ba9bbe8e5da7.tar.xz linux-dev-45cac65b0fcd287ebb877b141d40ba9bbe8e5da7.zip | |
readahead: fault retry breaks mmap file read random detection
.fault now can retry. The retry can break state machine of .fault. In
filemap_fault, if page is miss, ra->mmap_miss is increased. In the second
try, since the page is in page cache now, ra->mmap_miss is decreased. And
these are done in one fault, so we can't detect random mmap file access.
Add a new flag to indicate .fault is tried once. In the second try, skip
ra->mmap_miss decreasing. The filemap_fault state machine is ok with it.
I only tested x86, didn't test other archs, but looks the change for other
archs is obvious, but who knows :)
Signed-off-by: Shaohua Li <shaohua.li@fusionio.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/mm.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index b01e585ab4b5..bcaab4e6fe91 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -161,6 +161,7 @@ extern pgprot_t protection_map[16]; #define FAULT_FLAG_ALLOW_RETRY 0x08 /* Retry fault if blocking */ #define FAULT_FLAG_RETRY_NOWAIT 0x10 /* Don't drop mmap_sem and wait when retrying */ #define FAULT_FLAG_KILLABLE 0x20 /* The fault task is in SIGKILL killable region */ +#define FAULT_FLAG_TRIED 0x40 /* second try */ /* * vm_fault is filled by the the pagefault handler and passed to the vma's |