+ mm-zsmalloc-remove-unused-zspage-isolated.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/zsmalloc: remove unused zspage->isolated
has been added to the -mm mm-unstable branch.  Its filename is
     mm-zsmalloc-remove-unused-zspage-isolated.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-unused-zspage-isolated.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@bytedance.com>
Subject: mm/zsmalloc: remove unused zspage->isolated
Date: Mon, 19 Feb 2024 13:33:53 +0000

The zspage->isolated is not used anywhere, we don't need to maintain it,
which needs to hold the heavy pool lock to update it, so just remove it.

Link: https://lkml.kernel.org/r/20240219-b4-szmalloc-migrate-v1-3-34cd49c6545b@bytedance.com
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/zsmalloc.c |   32 --------------------------------
 1 file changed, 32 deletions(-)

--- a/mm/zsmalloc.c~mm-zsmalloc-remove-unused-zspage-isolated
+++ a/mm/zsmalloc.c
@@ -116,7 +116,6 @@
 #define HUGE_BITS	1
 #define FULLNESS_BITS	4
 #define CLASS_BITS	8
-#define ISOLATED_BITS	5
 #define MAGIC_VAL_BITS	8
 
 #define MAX(a, b) ((a) >= (b) ? (a) : (b))
@@ -246,7 +245,6 @@ struct zspage {
 		unsigned int huge:HUGE_BITS;
 		unsigned int fullness:FULLNESS_BITS;
 		unsigned int class:CLASS_BITS + 1;
-		unsigned int isolated:ISOLATED_BITS;
 		unsigned int magic:MAGIC_VAL_BITS;
 	};
 	unsigned int inuse;
@@ -1732,17 +1730,6 @@ static void migrate_write_unlock(struct
 }
 
 #ifdef CONFIG_COMPACTION
-/* Number of isolated subpage for *page migration* in this zspage */
-static void inc_zspage_isolation(struct zspage *zspage)
-{
-	zspage->isolated++;
-}
-
-static void dec_zspage_isolation(struct zspage *zspage)
-{
-	VM_BUG_ON(zspage->isolated == 0);
-	zspage->isolated--;
-}
 
 static const struct movable_operations zsmalloc_mops;
 
@@ -1771,21 +1758,12 @@ static void replace_sub_page(struct size
 
 static bool zs_page_isolate(struct page *page, isolate_mode_t mode)
 {
-	struct zs_pool *pool;
-	struct zspage *zspage;
-
 	/*
 	 * Page is locked so zspage couldn't be destroyed. For detail, look at
 	 * lock_zspage in free_zspage.
 	 */
 	VM_BUG_ON_PAGE(PageIsolated(page), page);
 
-	zspage = get_zspage(page);
-	pool = zspage->pool;
-	spin_lock(&pool->lock);
-	inc_zspage_isolation(zspage);
-	spin_unlock(&pool->lock);
-
 	return true;
 }
 
@@ -1850,7 +1828,6 @@ static int zs_page_migrate(struct page *
 	kunmap_atomic(s_addr);
 
 	replace_sub_page(class, zspage, newpage, page);
-	dec_zspage_isolation(zspage);
 	/*
 	 * Since we complete the data copy and set up new zspage structure,
 	 * it's okay to release the pool's lock.
@@ -1872,16 +1849,7 @@ static int zs_page_migrate(struct page *
 
 static void zs_page_putback(struct page *page)
 {
-	struct zs_pool *pool;
-	struct zspage *zspage;
-
 	VM_BUG_ON_PAGE(!PageIsolated(page), page);
-
-	zspage = get_zspage(page);
-	pool = zspage->pool;
-	spin_lock(&pool->lock);
-	dec_zspage_isolation(zspage);
-	spin_unlock(&pool->lock);
 }
 
 static const struct movable_operations zsmalloc_mops = {
_

Patches currently in -mm which might be from zhouchengming@bytedance.com 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