FS-Cache: Recruit a page flags for cache management
Recruit a page flag to aid in cache management. The following extra flag is
defined:
(1) PG_fscache (PG_private_2)
The marked page is backed by a local cache and is pinning resources in the
cache driver.
If PG_fscache is set, then things that checked for PG_private will now also
check for that. This includes things like truncation and page invalidation.
The function page_has_private() had been added to make the checks for both
PG_private and PG_private_2 at the same time.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
diff --git a/mm/filemap.c b/mm/filemap.c
index 126d397..cbc5772 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2463,6 +2463,9 @@
* (presumably at page->private). If the release was successful, return `1'.
* Otherwise return zero.
*
+ * This may also be called if PG_fscache is set on a page, indicating that the
+ * page is known to the local caching routines.
+ *
* The @gfp_mask argument specifies whether I/O may be performed to release
* this page (__GFP_IO), and whether the call may block (__GFP_WAIT & __GFP_FS).
*
diff --git a/mm/migrate.c b/mm/migrate.c
index a9eff3f..068655d 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -250,7 +250,7 @@
* The number of remaining references must be:
* 1 for anonymous pages without a mapping
* 2 for pages with a mapping
- * 3 for pages with a mapping and PagePrivate set.
+ * 3 for pages with a mapping and PagePrivate/PagePrivate2 set.
*/
static int migrate_page_move_mapping(struct address_space *mapping,
struct page *newpage, struct page *page)
@@ -270,7 +270,7 @@
pslot = radix_tree_lookup_slot(&mapping->page_tree,
page_index(page));
- expected_count = 2 + !!PagePrivate(page);
+ expected_count = 2 + !!page_has_private(page);
if (page_count(page) != expected_count ||
(struct page *)radix_tree_deref_slot(pslot) != page) {
spin_unlock_irq(&mapping->tree_lock);
@@ -386,7 +386,7 @@
/*
* Common logic to directly migrate a single page suitable for
- * pages that do not use PagePrivate.
+ * pages that do not use PagePrivate/PagePrivate2.
*
* Pages are locked upon entry and exit.
*/
@@ -522,7 +522,7 @@
* Buffers may be managed in a filesystem specific way.
* We must have no buffers or drop them.
*/
- if (PagePrivate(page) &&
+ if (page_has_private(page) &&
!try_to_release_page(page, GFP_KERNEL))
return -EAGAIN;
@@ -655,7 +655,7 @@
* free the metadata, so the page can be freed.
*/
if (!page->mapping) {
- if (!PageAnon(page) && PagePrivate(page)) {
+ if (!PageAnon(page) && page_has_private(page)) {
/*
* Go direct to try_to_free_buffers() here because
* a) that's what try_to_release_page() would do anyway
diff --git a/mm/readahead.c b/mm/readahead.c
index 6be9275..133b6d5 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -33,14 +33,15 @@
/*
* see if a page needs releasing upon read_cache_pages() failure
- * - the caller of read_cache_pages() may have set PG_private before calling,
- * such as the NFS fs marking pages that are cached locally on disk, thus we
- * need to give the fs a chance to clean up in the event of an error
+ * - the caller of read_cache_pages() may have set PG_private or PG_fscache
+ * before calling, such as the NFS fs marking pages that are cached locally
+ * on disk, thus we need to give the fs a chance to clean up in the event of
+ * an error
*/
static void read_cache_pages_invalidate_page(struct address_space *mapping,
struct page *page)
{
- if (PagePrivate(page)) {
+ if (page_has_private(page)) {
if (!trylock_page(page))
BUG();
page->mapping = mapping;
diff --git a/mm/swap.c b/mm/swap.c
index 6e83084..bede23c 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -448,8 +448,8 @@
for (i = 0; i < pagevec_count(pvec); i++) {
struct page *page = pvec->pages[i];
- if (PagePrivate(page) && trylock_page(page)) {
- if (PagePrivate(page))
+ if (page_has_private(page) && trylock_page(page)) {
+ if (page_has_private(page))
try_to_release_page(page, 0);
unlock_page(page);
}
diff --git a/mm/truncate.c b/mm/truncate.c
index 1229211..55206fa 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -50,7 +50,7 @@
static inline void truncate_partial_page(struct page *page, unsigned partial)
{
zero_user_segment(page, partial, PAGE_CACHE_SIZE);
- if (PagePrivate(page))
+ if (page_has_private(page))
do_invalidatepage(page, partial);
}
@@ -99,7 +99,7 @@
if (page->mapping != mapping)
return;
- if (PagePrivate(page))
+ if (page_has_private(page))
do_invalidatepage(page, 0);
cancel_dirty_page(page, PAGE_CACHE_SIZE);
@@ -126,7 +126,7 @@
if (page->mapping != mapping)
return 0;
- if (PagePrivate(page) && !try_to_release_page(page, 0))
+ if (page_has_private(page) && !try_to_release_page(page, 0))
return 0;
clear_page_mlock(page);
@@ -348,7 +348,7 @@
if (page->mapping != mapping)
return 0;
- if (PagePrivate(page) && !try_to_release_page(page, GFP_KERNEL))
+ if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL))
return 0;
spin_lock_irq(&mapping->tree_lock);
@@ -356,7 +356,7 @@
goto failed;
clear_page_mlock(page);
- BUG_ON(PagePrivate(page));
+ BUG_ON(page_has_private(page));
__remove_from_page_cache(page);
spin_unlock_irq(&mapping->tree_lock);
page_cache_release(page); /* pagecache ref */
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 06e7269..4252449 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -283,7 +283,7 @@
static inline int is_page_cache_freeable(struct page *page)
{
- return page_count(page) - !!PagePrivate(page) == 2;
+ return page_count(page) - !!page_has_private(page) == 2;
}
static int may_write_to_queue(struct backing_dev_info *bdi)
@@ -367,7 +367,7 @@
* Some data journaling orphaned pages can have
* page->mapping == NULL while being dirty with clean buffers.
*/
- if (PagePrivate(page)) {
+ if (page_has_private(page)) {
if (try_to_free_buffers(page)) {
ClearPageDirty(page);
printk("%s: orphaned page\n", __func__);
@@ -727,7 +727,7 @@
* process address space (page_count == 1) it can be freed.
* Otherwise, leave the page on the LRU so it is swappable.
*/
- if (PagePrivate(page)) {
+ if (page_has_private(page)) {
if (!try_to_release_page(page, sc->gfp_mask))
goto activate_locked;
if (!mapping && page_count(page) == 1) {