The patch titled
mm-reuse-unused-swap-entry-if-necessary-update
has been added to the -mm tree. Its filename is
mm-reuse-unused-swap-entry-if-necessary-update.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: mm-reuse-unused-swap-entry-if-necessary-update
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
This is a replacement for
mm-reuse-unused-swap-entry-if-necessary.patch in mmotm.
function is renamed and comments are added.
Acked-by: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
Cc: Hugh Dickins <hugh.dickins@xxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Li Zefan <lizf@xxxxxxxxxxxxxx>
Cc: Dhaval Giani <dhaval@xxxxxxxxxxxxxxxxxx>
Cc: YAMAMOTO Takashi <yamamoto@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/swapfile.c | 22 +++++++++++++++-------
1 file changed, 15 insertions(+), 7 deletions(-)
diff -puN mm/swapfile.c~mm-reuse-unused-swap-entry-if-necessary-update mm/swapfile.c
--- a/mm/swapfile.c~mm-reuse-unused-swap-entry-if-necessary-update
+++ a/mm/swapfile.c
@@ -79,9 +79,9 @@ static inline unsigned short encode_swap
return ret;
}
-
+/* returnes 1 if swap entry is freed */
static int
-try_to_reuse_swap(struct swap_info_struct *si, unsigned long offset)
+__try_to_reclaim_swap(struct swap_info_struct *si, unsigned long offset)
{
int type = si - swap_info;
swp_entry_t entry = swp_entry(type, offset);
@@ -91,6 +91,13 @@ try_to_reuse_swap(struct swap_info_struc
page = find_get_page(&swapper_space, entry.val);
if (!page)
return 0;
+ /*
+ * This function is called from scan_swap_map() and it's called
+ * by vmscan.c at reclaiming pages. So, we hold a lock on a page, here.
+ * We have to use trylock for avoiding deadlock. This is a special
+ * case and you should use try_to_free_swap() with explicit lock_page()
+ * in usual operations.
+ */
if (trylock_page(page)) {
ret = try_to_free_swap(page);
unlock_page(page);
@@ -323,13 +330,14 @@ checks:
/* reuse swap entry of cache-only swap if not busy. */
if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) {
- int ret;
+ int swap_was_freed;
spin_unlock(&swap_lock);
- ret = try_to_reuse_swap(si, offset);
+ swap_was_freed = __try_to_reclaim_swap(si, offset);
spin_lock(&swap_lock);
- if (ret)
- goto checks; /* we released swap_lock. retry. */
- goto scan; /* In some racy case */
+ /* entry was freed successfully, try to use this again */
+ if (swap_was_freed)
+ goto checks;
+ goto scan; /* check next one */
}
if (si->swap_map[offset])
_
Patches currently in -mm which might be from kamezawa.hiroyu@xxxxxxxxxxxxxx are
origin.patch
migration-only-migrate_prep-once-per-move_pages.patch
page-allocator-use-integer-fields-lookup-for-gfp_zone-and-check-for-errors-in-flags-passed-to-the-page-allocator.patch
page-allocator-use-integer-fields-lookup-for-gfp_zone-and-check-for-errors-in-flags-passed-to-the-page-allocator-fix-gfp-zone-patch.patch
mm-add-swap-cache-interface-for-swap-reference.patch
mm-modify-swap_map-and-add-swap_has_cache-flag.patch
mm-modify-swap_map-and-add-swap_has_cache-flag-update.patch
mm-reuse-unused-swap-entry-if-necessary.patch
mm-reuse-unused-swap-entry-if-necessary-update.patch
cgroups-forbid-noprefix-if-mounting-more-than-just-cpuset-subsystem.patch
cgroups-forbid-noprefix-if-mounting-more-than-just-cpuset-subsystem-fix.patch
cgroups-forbid-noprefix-if-mounting-more-than-just-cpuset-subsystem-fix2.patch
memcg-add-file-based-rss-accounting.patch
memcg-add-file-based-rss-accounting-fix-mem_cgroup_update_mapped_file_stat-oops.patch
memcg-remove-mem_cgroup_cache_charge_swapin.patch
memcg-remove-some-redundant-checks.patch
memcg-remove-unneeded-forward-declaration-from-schedh.patch
memcg-fix-swap-accounting.patch
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