[merged mm-stable] zsmalloc-do-not-scan-for-allocated-objects-in-empty-zspage.patch removed from -mm tree

[merged mm-stable] zsmalloc-do-not-scan-for-allocated-objects-in-empty-zspage.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: zsmalloc: do not scan for allocated objects in empty zspage
has been removed from the -mm tree.  Its filename was
     zsmalloc-do-not-scan-for-allocated-objects-in-empty-zspage.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Sergey Senozhatsky <senozhatsky@chromium.org>
Subject: zsmalloc: do not scan for allocated objects in empty zspage
Date: Sat, 24 Jun 2023 14:12:14 +0900

Patch series "zsmalloc: small compaction improvements", v2.

A tiny series that can reduce the number of find_alloced_obj() invocations
(which perform a linear scan of sub-page) during compaction.  Inspired by
Alexey Romanov's findings.


This patch (of 3):

zspage migration can terminate as soon as it moves the last allocated
object from the source zspage.  Add a simple helper zspage_empty() that
tests zspage ->inuse on each migration iteration.

Link: https://lkml.kernel.org/r/20230624053120.643409-2-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Suggested-by: Alexey Romanov <AVRomanov@sberdevices.ru>
Reviewed-by: Alexey Romanov <avromanov@sberdevices.ru>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/zsmalloc.c |    9 +++++++++
 1 file changed, 9 insertions(+)

--- a/mm/zsmalloc.c~zsmalloc-do-not-scan-for-allocated-objects-in-empty-zspage
+++ a/mm/zsmalloc.c
@@ -1147,6 +1147,11 @@ static bool zspage_full(struct size_clas
 	return get_zspage_inuse(zspage) == class->objs_per_zspage;
 }
 
+static bool zspage_empty(struct zspage *zspage)
+{
+	return get_zspage_inuse(zspage) == 0;
+}
+
 /**
  * zs_lookup_class_index() - Returns index of the zsmalloc &size_class
  * that hold objects of the provided size.
@@ -1625,6 +1630,10 @@ static void migrate_zspage(struct zs_poo
 		obj_idx++;
 		record_obj(handle, free_obj);
 		obj_free(class->size, used_obj);
+
+		/* Stop if there are no more objects to migrate */
+		if (zspage_empty(get_zspage(s_page)))
+			break;
 	}
 
 	/* Remember last position in this iteration */
_

Patches currently in -mm which might be from senozhatsky@chromium.org are