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authorAndy Whitcroft <apw@canonical.com>2010-07-29 09:46:41 +0100
committerJohn Rigby <john.rigby@linaro.org>2011-11-16 14:25:06 -0700
commite212ee5bf1c2e5e55c8ac612673ddee5b1269251 (patch)
tree3cab1e8fde82aeab2b27651cb381dffa947286e0 /mm
parent20c6952cbab3c3d3d5d26374a9455f5da988d314 (diff)
downloadlinux-linaro-precise-e212ee5bf1c2e5e55c8ac612673ddee5b1269251.tar.gz
UBUNTU: SAUCE: (no-up) add tracing for user initiated readahead requests
Track pages which undergo readahead and for each record which were actually consumed, via either read or faulted into a map. This allows userspace readahead applications (such as ureadahead) to track which pages in core at the end of a boot are actually required and generate an optimal readahead pack. It also allows pack adjustment and optimisation in parallel with readahead, allowing the pack to evolve to be accurate as userspace paths change. The status of the pages are reported back via the mincore() call using a newly allocated bit. Signed-off-by: Andy Whitcroft <apw@canonical.com> Acked-by: Stefan Bader <stefan.bader@canonical.com> Signed-off-by: Leann Ogasawara <leann.ogasawara@canonical.com>
Diffstat (limited to 'mm')
-rw-r--r--mm/filemap.c3
-rw-r--r--mm/memory.c7
-rw-r--r--mm/mincore.c2
-rw-r--r--mm/readahead.c1
4 files changed, 12 insertions, 1 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 7771871fa35..93e2105bb98 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1327,6 +1327,9 @@ int file_read_actor(read_descriptor_t *desc, struct page *page,
if (size > count)
size = count;
+ if (PageReadaheadUnused(page))
+ ClearPageReadaheadUnused(page);
+
/*
* Faults on the destination of a read are common, so do it before
* taking the kmap.
diff --git a/mm/memory.c b/mm/memory.c
index b2b87315cdc..7d5c2a5ee1b 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3203,10 +3203,15 @@ static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
else
VM_BUG_ON(!PageLocked(vmf.page));
+ page = vmf.page;
+
+ /* Mark the page as used on fault. */
+ if (PageReadaheadUnused(page))
+ ClearPageReadaheadUnused(page);
+
/*
* Should we do an early C-O-W break?
*/
- page = vmf.page;
if (flags & FAULT_FLAG_WRITE) {
if (!(vma->vm_flags & VM_SHARED)) {
page = cow_page;
diff --git a/mm/mincore.c b/mm/mincore.c
index 636a86876ff..a0c0d1e64ef 100644
--- a/mm/mincore.c
+++ b/mm/mincore.c
@@ -80,6 +80,8 @@ static unsigned char mincore_page(struct address_space *mapping, pgoff_t pgoff)
#endif
if (page) {
present = PageUptodate(page);
+ if (present)
+ present |= (PageReadaheadUnused(page) << 7);
page_cache_release(page);
}
diff --git a/mm/readahead.c b/mm/readahead.c
index 867f9dd82dc..133722cc55f 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -187,6 +187,7 @@ __do_page_cache_readahead(struct address_space *mapping, struct file *filp,
list_add(&page->lru, &page_pool);
if (page_idx == nr_to_read - lookahead_size)
SetPageReadahead(page);
+ SetPageReadaheadUnused(page);
ret++;
}