The patch titled
readahead: convert filemap invocations
has been added to the -mm tree. Its filename is
readahead-convert-filemap-invocations.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: readahead: convert filemap invocations
From: Fengguang Wu <wfg@xxxxxxxxxxxxxxxx>
Convert filemap reads to use on-demand readahead.
The new call scheme is to
- call readahead on non-cached page
- call readahead on look-ahead page
- update prev_index when finished with the read request
Signed-off-by: Fengguang Wu <wfg@xxxxxxxxxxxxxxxx>
Cc: Steven Pratt <slpratt@xxxxxxxxxxxxxx>
Cc: Ram Pai <linuxram@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/filemap.c | 51 +++++++++++++++++++++++++++++--------------------
1 file changed, 31 insertions(+), 20 deletions(-)
diff -puN mm/filemap.c~readahead-convert-filemap-invocations mm/filemap.c
--- a/mm/filemap.c~readahead-convert-filemap-invocations
+++ a/mm/filemap.c
@@ -908,15 +908,20 @@ void do_generic_mapping_read(struct addr
nr = nr - offset;
cond_resched();
- if (index == next_index)
- next_index = page_cache_readahead(mapping, &ra, filp,
- index, last_index - index);
-
find_page:
page = find_get_page(mapping, index);
- if (unlikely(page == NULL)) {
- handle_ra_miss(mapping, &ra, index);
- goto no_cached_page;
+ if (!page) {
+ page_cache_readahead_ondemand(mapping,
+ &ra, filp, page,
+ index, last_index - index);
+ page = find_get_page(mapping, index);
+ if (unlikely(page == NULL))
+ goto no_cached_page;
+ }
+ if (PageReadahead(page)) {
+ page_cache_readahead_ondemand(mapping,
+ &ra, filp, page,
+ index, last_index - index);
}
if (!PageUptodate(page))
goto page_not_up_to_date;
@@ -1067,6 +1072,7 @@ no_cached_page:
out:
*_ra = ra;
+ _ra->prev_index = prev_index;
*ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset;
if (cached_page)
@@ -1370,26 +1376,30 @@ struct page *filemap_fault(struct vm_are
goto no_cached_page;
/*
- * The readahead code wants to be told about each and every page
- * so it can build and shrink its windows appropriately
- *
- * For sequential accesses, we use the generic readahead logic.
- */
- if (VM_SequentialReadHint(vma))
- page_cache_readahead(mapping, ra, file, fdata->pgoff, 1);
-
- /*
* Do we have something in the page cache already?
*/
retry_find:
page = find_lock_page(mapping, fdata->pgoff);
+ /*
+ * For sequential accesses, we use the generic readahead logic.
+ */
+ if (VM_SequentialReadHint(vma)) {
+ if (!page) {
+ page_cache_readahead_ondemand(mapping, ra, file, page,
+ fdata->pgoff, 1);
+ page = find_lock_page(mapping, fdata->pgoff);
+ if (!page)
+ goto no_cached_page;
+ }
+ if (PageReadahead(page)) {
+ page_cache_readahead_ondemand(mapping, ra, file, page,
+ fdata->pgoff, 1);
+ }
+ }
+
if (!page) {
unsigned long ra_pages;
- if (VM_SequentialReadHint(vma)) {
- handle_ra_miss(mapping, ra, fdata->pgoff);
- goto no_cached_page;
- }
ra->mmap_miss++;
/*
@@ -1442,6 +1452,7 @@ retry_find:
* Found the page and have a reference on it.
*/
mark_page_accessed(page);
+ ra->prev_index = page->index;
return page;
outside_data_content:
_
Patches currently in -mm which might be from wfg@xxxxxxxxxxxxxxxx are
readahead-introduce-pg_readahead.patch
readahead-add-look-ahead-support-to-__do_page_cache_readahead.patch
readahead-min_ra_pages-max_ra_pages-macros.patch
readahead-data-structure-and-routines.patch
readahead-on-demand-readahead-logic.patch
readahead-convert-filemap-invocations.patch
readahead-convert-splice-invocations.patch
readahead-convert-ext3-ext4-invocations.patch
readahead-remove-the-old-algorithm.patch
-
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