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author | Fengguang Wu <wfg@mail.ustc.edu.cn> | 2007-07-19 01:48:02 -0700 |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-19 10:04:44 -0700 |
commit | 3ea89ee86a82e9fbde37018d9b9e92a552e5fd13 (patch) | |
tree | 5fef7216ef39d66684754e4aadf368ce9adfd72e /mm | |
parent | 122a21d11cbfda6d1e33cbc8ae9e4c4ee2f1886e (diff) | |
download | linux-3ea89ee86a82e9fbde37018d9b9e92a552e5fd13.tar.gz linux-3ea89ee86a82e9fbde37018d9b9e92a552e5fd13.tar.xz |
readahead: convert filemap invocations
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@mail.ustc.edu.cn>
Cc: Steven Pratt <slpratt@austin.ibm.com>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/filemap.c | 51 |
1 files changed, 31 insertions, 20 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 4fd9e3f0f48a..5eb0a6b9d607 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -891,15 +891,20 @@ void do_generic_mapping_read(struct address_space *mapping, unsigned long nr, ret; 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; @@ -1051,6 +1056,7 @@ no_cached_page: out: *_ra = ra; + _ra->prev_index = prev_index; *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; if (cached_page) @@ -1333,26 +1339,30 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 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, vmf->pgoff, 1); - - /* * Do we have something in the page cache already? */ retry_find: page = find_lock_page(mapping, vmf->pgoff); + /* + * For sequential accesses, we use the generic readahead logic. + */ + if (VM_SequentialReadHint(vma)) { + if (!page) { + page_cache_readahead_ondemand(mapping, ra, file, page, + vmf->pgoff, 1); + page = find_lock_page(mapping, vmf->pgoff); + if (!page) + goto no_cached_page; + } + if (PageReadahead(page)) { + page_cache_readahead_ondemand(mapping, ra, file, page, + vmf->pgoff, 1); + } + } + if (!page) { unsigned long ra_pages; - if (VM_SequentialReadHint(vma)) { - handle_ra_miss(mapping, ra, vmf->pgoff); - goto no_cached_page; - } ra->mmap_miss++; /* @@ -1405,6 +1415,7 @@ retry_find: * Found the page and have a reference on it. */ mark_page_accessed(page); + ra->prev_index = page->index; vmf->page = page; return ret | VM_FAULT_LOCKED; |