The patch titled
Subject: mm/zsmalloc: remove migrate_write_lock_nested()
has been added to the -mm mm-unstable branch. Its filename is
mm-zsmalloc-remove-migrate_write_lock_nested.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-zsmalloc-remove-migrate_write_lock_nested.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
Subject: mm/zsmalloc: remove migrate_write_lock_nested()
Date: Mon, 19 Feb 2024 13:33:52 +0000
The migrate write lock is to protect the race between zspage migration and
zspage objects' map users.
We only need to lock out the map users of src zspage, not dst zspage,
which is safe to map by users concurrently, since we only need to do
obj_malloc() from dst zspage.
So we can remove the migrate_write_lock_nested() use case.
As we are here, cleanup the __zs_compact() by moving putback_zspage()
outside of migrate_write_unlock since we hold pool lock, no malloc or free
users can come in.
Link: https://lkml.kernel.org/r/20240219-b4-szmalloc-migrate-v1-2-34cd49c6545b@xxxxxxxxxxxxx
Signed-off-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Nhat Pham <nphamcs@xxxxxxxxx>
Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/zsmalloc.c | 22 +++++-----------------
1 file changed, 5 insertions(+), 17 deletions(-)
--- a/mm/zsmalloc.c~mm-zsmalloc-remove-migrate_write_lock_nested
+++ a/mm/zsmalloc.c
@@ -279,7 +279,6 @@ static void migrate_lock_init(struct zsp
static void migrate_read_lock(struct zspage *zspage);
static void migrate_read_unlock(struct zspage *zspage);
static void migrate_write_lock(struct zspage *zspage);
-static void migrate_write_lock_nested(struct zspage *zspage);
static void migrate_write_unlock(struct zspage *zspage);
#ifdef CONFIG_COMPACTION
@@ -1727,11 +1726,6 @@ static void migrate_write_lock(struct zs
write_lock(&zspage->lock);
}
-static void migrate_write_lock_nested(struct zspage *zspage)
-{
- write_lock_nested(&zspage->lock, SINGLE_DEPTH_NESTING);
-}
-
static void migrate_write_unlock(struct zspage *zspage)
{
write_unlock(&zspage->lock);
@@ -2003,19 +1997,17 @@ static unsigned long __zs_compact(struct
dst_zspage = isolate_dst_zspage(class);
if (!dst_zspage)
break;
- migrate_write_lock(dst_zspage);
}
src_zspage = isolate_src_zspage(class);
if (!src_zspage)
break;
- migrate_write_lock_nested(src_zspage);
-
+ migrate_write_lock(src_zspage);
migrate_zspage(pool, src_zspage, dst_zspage);
- fg = putback_zspage(class, src_zspage);
migrate_write_unlock(src_zspage);
+ fg = putback_zspage(class, src_zspage);
if (fg == ZS_INUSE_RATIO_0) {
free_zspage(pool, class, src_zspage);
pages_freed += class->pages_per_zspage;
@@ -2025,7 +2017,6 @@ static unsigned long __zs_compact(struct
if (get_fullness_group(class, dst_zspage) == ZS_INUSE_RATIO_100
|| spin_is_contended(&pool->lock)) {
putback_zspage(class, dst_zspage);
- migrate_write_unlock(dst_zspage);
dst_zspage = NULL;
spin_unlock(&pool->lock);
@@ -2034,15 +2025,12 @@ static unsigned long __zs_compact(struct
}
}
- if (src_zspage) {
+ if (src_zspage)
putback_zspage(class, src_zspage);
- migrate_write_unlock(src_zspage);
- }
- if (dst_zspage) {
+ if (dst_zspage)
putback_zspage(class, dst_zspage);
- migrate_write_unlock(dst_zspage);
- }
+
spin_unlock(&pool->lock);
return pages_freed;
_
Patches currently in -mm which might be from zhouchengming@xxxxxxxxxxxxx are
mm-zswap-invalidate-duplicate-entry-when-zswap_enabled.patch
mm-zswap-make-sure-each-swapfile-always-have-zswap-rb-tree.patch
mm-zswap-split-zswap-rb-tree.patch
mm-zswap-fix-race-between-lru-writeback-and-swapoff.patch
mm-list_lru-remove-list_lru_putback.patch
mm-zswap-add-more-comments-in-shrink_memcg_cb.patch
mm-zswap-invalidate-zswap-entry-when-swap-entry-free.patch
mm-zswap-stop-lru-list-shrinking-when-encounter-warm-region.patch
mm-zswap-remove-duplicate_entry-debug-value.patch
mm-zswap-only-support-zswap_exclusive_loads_enabled.patch
mm-zswap-zswap-entry-doesnt-need-refcount-anymore.patch
mm-zswap-optimize-and-cleanup-the-invalidation-of-duplicate-entry.patch
mm-zsmalloc-fix-migrate_write_lock-when-config_compaction.patch
mm-zsmalloc-remove-migrate_write_lock_nested.patch
mm-zsmalloc-remove-unused-zspage-isolated.patch
