Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=7ff81078d8b9f3d05a27b7bd3786ffb1ef1b0d1f
Commit: 7ff81078d8b9f3d05a27b7bd3786ffb1ef1b0d1f
Parent: 6b10c6c9fbfe754e8482efb8c8b84f8e40c0f2eb
Author: Fengguang Wu <[EMAIL PROTECTED]>
AuthorDate: Tue Oct 16 01:24:35 2007 -0700
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Tue Oct 16 09:42:52 2007 -0700
readahead: remove the local copy of ra in do_generic_mapping_read()
The local copy of ra in do_generic_mapping_read() can now go away.
It predates readanead(req_size). In a time when the readahead code was
called
on *every* single page. Hence a local has to be made to reduce the chance
of
the readahead state being overwritten by a concurrent reader. More details
in: Linux: Random File I/O Regressions In 2.6
<http://kerneltrap.org/node/3039>
Cc: Nick Piggin <[EMAIL PROTECTED]>
Signed-off-by: Fengguang Wu <[EMAIL PROTECTED]>
Cc: Rusty Russell <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
mm/filemap.c | 20 +++++++++-----------
1 files changed, 9 insertions(+), 11 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index bbcca45..3c97bdc 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -859,7 +859,7 @@ static void shrink_readahead_size_eio(struct file *filp,
* It may be NULL.
*/
void do_generic_mapping_read(struct address_space *mapping,
- struct file_ra_state *_ra,
+ struct file_ra_state *ra,
struct file *filp,
loff_t *ppos,
read_descriptor_t *desc,
@@ -874,13 +874,12 @@ void do_generic_mapping_read(struct address_space
*mapping,
unsigned int prev_offset;
struct page *cached_page;
int error;
- struct file_ra_state ra = *_ra;
cached_page = NULL;
index = *ppos >> PAGE_CACHE_SHIFT;
next_index = index;
- prev_index = ra.prev_pos >> PAGE_CACHE_SHIFT;
- prev_offset = ra.prev_pos & (PAGE_CACHE_SIZE-1);
+ prev_index = ra->prev_pos >> PAGE_CACHE_SHIFT;
+ prev_offset = ra->prev_pos & (PAGE_CACHE_SIZE-1);
last_index = (*ppos + desc->count + PAGE_CACHE_SIZE-1) >>
PAGE_CACHE_SHIFT;
offset = *ppos & ~PAGE_CACHE_MASK;
@@ -895,7 +894,7 @@ find_page:
page = find_get_page(mapping, index);
if (!page) {
page_cache_sync_readahead(mapping,
- &ra, filp,
+ ra, filp,
index, last_index - index);
page = find_get_page(mapping, index);
if (unlikely(page == NULL))
@@ -903,7 +902,7 @@ find_page:
}
if (PageReadahead(page)) {
page_cache_async_readahead(mapping,
- &ra, filp, page,
+ ra, filp, page,
index, last_index - index);
}
if (!PageUptodate(page))
@@ -1014,7 +1013,7 @@ readpage:
}
unlock_page(page);
error = -EIO;
- shrink_readahead_size_eio(filp, &ra);
+ shrink_readahead_size_eio(filp, ra);
goto readpage_error;
}
unlock_page(page);
@@ -1054,10 +1053,9 @@ no_cached_page:
}
out:
- *_ra = ra;
- _ra->prev_pos = prev_index;
- _ra->prev_pos <<= PAGE_CACHE_SHIFT;
- _ra->prev_pos |= prev_offset;
+ ra->prev_pos = prev_index;
+ ra->prev_pos <<= PAGE_CACHE_SHIFT;
+ ra->prev_pos |= prev_offset;
*ppos = ((loff_t)index << PAGE_CACHE_SHIFT) + offset;
if (cached_page)
-
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