The patch titled
tmpfs: move swap swizzling into shmem
has been added to the -mm tree. Its filename is
tmpfs-move-swap-swizzling-into-shmem.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: tmpfs: move swap swizzling into shmem
From: Hugh Dickins <hugh@xxxxxxxxxxx>
move_to_swap_cache and move_from_swap_cache functions (which swizzle a page
between tmpfs page cache and swap cache, to avoid page copying) are only used
by shmem.c; and our subsequent fix for unionfs needs different treatments in
the two instances of move_from_swap_cache. Move them from swap_state.c into
their callsites shmem_writepage, shmem_unuse_inode and shmem_getpage, making
add_to_swap_cache externally visible.
shmem.c likes to say set_page_dirty where swap_state.c liked to say
SetPageDirty: respect that diversity, which __set_page_dirty_no_writeback
makes moot (and implies we should lose that "shift page from clean_pages to
dirty_pages list" comment: it's on neither).
Signed-off-by: Hugh Dickins <hugh@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/swap.h | 15 ++++-----------
mm/shmem.c | 16 ++++++++++++----
mm/swap_state.c | 35 +----------------------------------
3 files changed, 17 insertions(+), 49 deletions(-)
diff -puN include/linux/swap.h~tmpfs-move-swap-swizzling-into-shmem include/linux/swap.h
--- a/include/linux/swap.h~tmpfs-move-swap-swizzling-into-shmem
+++ a/include/linux/swap.h
@@ -220,11 +220,9 @@ extern struct address_space swapper_spac
#define total_swapcache_pages swapper_space.nrpages
extern void show_swap_cache_info(void);
extern int add_to_swap(struct page *, gfp_t);
+extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
extern void __delete_from_swap_cache(struct page *);
extern void delete_from_swap_cache(struct page *);
-extern int move_to_swap_cache(struct page *, swp_entry_t);
-extern int move_from_swap_cache(struct page *, unsigned long,
- struct address_space *);
extern void free_page_and_swap_cache(struct page *);
extern void free_pages_and_swap_cache(struct page **, int);
extern struct page *lookup_swap_cache(swp_entry_t);
@@ -319,15 +317,10 @@ static inline struct page *lookup_swap_c
#define can_share_swap_page(p) (page_mapcount(p) == 1)
-static inline int move_to_swap_cache(struct page *page, swp_entry_t entry)
+static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
+ gfp_t gfp_mask)
{
- return 1;
-}
-
-static inline int move_from_swap_cache(struct page *page, unsigned long index,
- struct address_space *mapping)
-{
- return 1;
+ return -1;
}
static inline void __delete_from_swap_cache(struct page *page)
diff -puN mm/shmem.c~tmpfs-move-swap-swizzling-into-shmem mm/shmem.c
--- a/mm/shmem.c~tmpfs-move-swap-swizzling-into-shmem
+++ a/mm/shmem.c
@@ -884,7 +884,9 @@ lost2:
found:
idx += offset;
inode = &info->vfs_inode;
- if (move_from_swap_cache(page, idx, inode->i_mapping) == 0) {
+ if (add_to_page_cache(page, inode->i_mapping, idx, GFP_ATOMIC) == 0) {
+ delete_from_swap_cache(page);
+ set_page_dirty(page);
info->flags |= SHMEM_PAGEIN;
shmem_swp_set(info, ptr + offset, 0);
}
@@ -972,7 +974,8 @@ static int shmem_writepage(struct page *
BUG_ON(!entry);
BUG_ON(entry->val);
- if (move_to_swap_cache(page, swap) == 0) {
+ if (add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) {
+ remove_from_page_cache(page);
shmem_swp_set(info, entry, swap.val);
shmem_swp_unmap(entry);
spin_unlock(&info->lock);
@@ -982,6 +985,9 @@ static int shmem_writepage(struct page *
list_move_tail(&info->swaplist, &shmem_swaplist);
spin_unlock(&shmem_swaplist_lock);
}
+ swap_duplicate(swap);
+ page_cache_release(page); /* pagecache ref */
+ set_page_dirty(page);
unlock_page(page);
return 0;
}
@@ -1217,13 +1223,15 @@ repeat:
SetPageUptodate(filepage);
set_page_dirty(filepage);
swap_free(swap);
- } else if (!(error = move_from_swap_cache(
- swappage, idx, mapping))) {
+ } else if (!(error = add_to_page_cache(
+ swappage, mapping, idx, GFP_ATOMIC))) {
info->flags |= SHMEM_PAGEIN;
shmem_swp_set(info, entry, 0);
shmem_swp_unmap(entry);
+ delete_from_swap_cache(swappage);
spin_unlock(&info->lock);
filepage = swappage;
+ set_page_dirty(filepage);
swap_free(swap);
} else {
shmem_swp_unmap(entry);
diff -puN mm/swap_state.c~tmpfs-move-swap-swizzling-into-shmem mm/swap_state.c
--- a/mm/swap_state.c~tmpfs-move-swap-swizzling-into-shmem
+++ a/mm/swap_state.c
@@ -67,8 +67,7 @@ void show_swap_cache_info(void)
* add_to_swap_cache resembles add_to_page_cache on swapper_space,
* but sets SwapCache flag and private instead of mapping and index.
*/
-static int add_to_swap_cache(struct page *page, swp_entry_t entry,
- gfp_t gfp_mask)
+int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp_mask)
{
int error;
@@ -183,38 +182,6 @@ void delete_from_swap_cache(struct page
page_cache_release(page);
}
-/*
- * Strange swizzling function only for use by shmem_writepage
- */
-int move_to_swap_cache(struct page *page, swp_entry_t entry)
-{
- int err = add_to_swap_cache(page, entry, GFP_ATOMIC);
- if (!err) {
- remove_from_page_cache(page);
- page_cache_release(page); /* pagecache ref */
- if (!swap_duplicate(entry))
- BUG();
- SetPageDirty(page);
- }
- return err;
-}
-
-/*
- * Strange swizzling function for shmem_getpage (and shmem_unuse)
- */
-int move_from_swap_cache(struct page *page, unsigned long index,
- struct address_space *mapping)
-{
- int err = add_to_page_cache(page, mapping, index, GFP_ATOMIC);
- if (!err) {
- delete_from_swap_cache(page);
- /* shift page from clean_pages to dirty_pages list */
- ClearPageDirty(page);
- set_page_dirty(page);
- }
- return err;
-}
-
/*
* If we are the only user, then try to free up the swap cache.
*
_
Patches currently in -mm which might be from hugh@xxxxxxxxxxx are
git-unionfs.patch
swapin_readahead-excise-numa-bogosity.patch
swapin_readahead-move-and-rearrange-args.patch
swapin-needs-gfp_mask-for-loop-on-tmpfs.patch
shmem-sgp_quick-and-sgp_fault-redundant.patch
shmem_getpage-return-page-locked.patch
shmem_file_write-is-redundant.patch
swapin-fix-valid_swaphandles-defect.patch
swapoff-scan-ptes-preemptibly.patch
shmem-factor-out-sbi-free_inodes-manipulations.patch
shmem-factor-out-sbi-free_inodes-manipulations-fix.patch
tmpfs-fix-mounts-when-size-is-less-than-the-page-size.patch
tmpfs-move-swap_state-stats-update.patch
tmpfs-shuffle-add_to_swap_caches.patch
tmpfs-move-swap-swizzling-into-shmem.patch
tmpfs-allow-filepage-alongside-swappage.patch
tmpfs-allocate-on-read-when-stacked.patch
tmpfs-make-shmem_unuse-more-preemptible.patch
tmpfs-open-a-window-in-shmem_unuse_inode.patch
tmpfs-radix_tree_preloading.patch
tmpfs-fix-shmem_swaplist-races.patch
maps4-add-proportional-set-size-accounting-in-smaps.patch
mm-dont-waste-swap-on-locked-pages.patch
skip-writing-data-pages-when-inode-is-under-i_sync.patch
printk-trivial-optimizations-fix.patch
r-o-bind-mounts-track-number-of-mount-writer-fix-buggy-loop.patch
r-o-bind-mounts-track-number-of-mount-writer-fix-buggy-loop-checkpatch-fixes.patch
memcgroup-temporarily-revert-swapoff-mod.patch
memory-controller-memory-accounting-v7.patch
memory-controller-add-per-container-lru-and-reclaim-v7-memcgroup-fix-try_to_free-order.patch
memcgroup-reinstate-swapoff-mod.patch
memcgroup-fix-zone-isolation-oom.patch
memcgroup-revert-swap_state-mods.patch
prio_tree-debugging-patch.patch
-
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