[028/178] mm/slab_common: provide "slab_merge" option for !IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT) builds

Commit Message

Andrew Morton April 30, 2021, 5:54 a.m. UTC

From: Rafael Aquini <[e-mail]>
Subject: mm/slab_common: provide "slab_merge" option for !IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT) builds

This is a minor addition to the allocator setup options to provide a
simple way to on demand enable back cache merging for builds that by
default run with CONFIG_SLAB_MERGE_DEFAULT not set.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Rafael Aquini <[e-mail]>
Cc: Christoph Lameter <[e-mail]>
Cc: Pekka Enberg <[e-mail]>
Cc: David Rientjes <[e-mail]>
Cc: Joonsoo Kim <[e-mail]>
Cc: Vlastimil Babka <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 Documentation/admin-guide/kernel-parameters.txt |    7 +++++++
 mm/slab_common.c                                |    8 ++++++++
 2 files changed, 15 insertions(+)

Patch

--- a/Documentation/admin-guide/kernel-parameters.txt~mm-slab_common-provide-slab_merge-option-for-is_enabledconfig_slab_merge_default-builds
+++ a/Documentation/admin-guide/kernel-parameters.txt
@@ -4996,6 +4996,10 @@ 
 
 	slram=		[HW,MTD]
 
+	slab_merge	[MM]
+			Enable merging of slabs with similar size when the
+			kernel is built without CONFIG_SLAB_MERGE_DEFAULT.
+
 	slab_nomerge	[MM]
 			Disable merging of slabs with similar size. May be
 			necessary if there is some reason to distinguish
@@ -5043,6 +5047,9 @@ 
 			lower than slub_max_order.
 			For more information see Documentation/vm/slub.rst.
 
+	slub_merge	[MM, SLUB]
+			Same with slab_merge.
+
 	slub_nomerge	[MM, SLUB]
 			Same with slab_nomerge. This is supported for legacy.
 			See slab_nomerge for more information.
--- a/mm/slab_common.c~mm-slab_common-provide-slab_merge-option-for-is_enabledconfig_slab_merge_default-builds
+++ a/mm/slab_common.c
@@ -71,11 +71,19 @@  static int __init setup_slab_nomerge(cha
 	return 1;
 }
 
+static int __init setup_slab_merge(char *str)
+{
+	slab_nomerge = false;
+	return 1;
+}
+
 #ifdef CONFIG_SLUB
 __setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0);
+__setup_param("slub_merge", slub_merge, setup_slab_merge, 0);
 #endif
 
 __setup("slab_nomerge", setup_slab_nomerge);
+__setup("slab_merge", setup_slab_merge);
 
 /*
  * Determine the size of a slab object