diff options
| author | Andy Whitcroft <apw@canonical.com> | 2010-07-29 09:46:41 +0100 |
|---|---|---|
| committer | John Rigby <john.rigby@linaro.org> | 2012-06-20 14:37:12 -0600 |
| commit | 1e680cc856551578b72f8c7726ccab6a471ce892 (patch) | |
| tree | 3c1adf47a5797802cb53775f0cdc96a266367cb0 | |
| parent | f8567008158dc530f10f4d1146fa2286abece923 (diff) | |
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>
| -rw-r--r-- | include/linux/page-flags.h | 3 | ||||
| -rw-r--r-- | mm/filemap.c | 3 | ||||
| -rw-r--r-- | mm/memory.c | 7 | ||||
| -rw-r--r-- | mm/mincore.c | 2 | ||||
| -rw-r--r-- | mm/readahead.c | 1 |
5 files changed, 15 insertions, 1 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index c88d2a9451a..3610ab7659f 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -108,6 +108,7 @@ enum pageflags { #ifdef CONFIG_TRANSPARENT_HUGEPAGE PG_compound_lock, #endif + PG_readaheadunused, /* user oriented readahead as yet unused*/ __NR_PAGEFLAGS, /* Filesystems */ @@ -231,6 +232,8 @@ PAGEFLAG(MappedToDisk, mappedtodisk) PAGEFLAG(Reclaim, reclaim) TESTCLEARFLAG(Reclaim, reclaim) PAGEFLAG(Readahead, reclaim) /* Reminder to do async read-ahead */ +PAGEFLAG(ReadaheadUnused, readaheadunused) + #ifdef CONFIG_HIGHMEM /* * Must use a macro here due to header dependency issues. page_zone() is not diff --git a/mm/filemap.c b/mm/filemap.c index 79c4b2b0b14..cfb3730d63b 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1305,6 +1305,9 @@ 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 6105f475fa8..2a5642005ae 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3234,10 +3234,15 @@ 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 936b4cee8cb..7c2874a9a73 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 cbcbb02f3e2..2acb81591a3 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++; } |