mm/slub: unify all sl[au]b parameters with "slab_$param"

Since the SLAB allocator has been removed, so we can clean up the
sl[au]b_$params. With only one slab allocator left, it's better to use the
generic "slab" term instead of "slub" which is an implementation detail,
which is pointed out by Vlastimil Babka. For more information please see
[1]. Hence, we are going to use "slab_$param" as the primary prefix.

This patch is changing the following slab parameters
- slub_max_order
- slub_min_order
- slub_min_objects
- slub_debug
to
- slab_max_order
- slab_min_order
- slab_min_objects
- slab_debug
as the primary slab parameters for all references of them in docs and
comments. But this patch won't change variables and functions inside
slub as we will have wider slub/slab change.

Meanwhile, "slub_$params" can also be passed by command line, which is
to keep backward compatibility. Also mark all "slub_$params" as legacy.

Remove the separate descriptions for slub_[no]merge, append legacy tip
for them at the end of descriptions of slab_[no]merge.

[1] https://lore.kernel.org/linux-mm/7512b350-4317-21a0-fab3-4101bc4d8f7a@suse.cz/

Signed-off-by: Xiongwei Song <xiongwei.song@windriver.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

1 files changed, 32 insertions, 39 deletions

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 89c67c2403fc..aefd68cec2e9 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5891,65 +5891,58 @@
 	simeth=		[IA-64]
 	simscsi=
 
-	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
-			allocs to different slabs, especially in hardened
-			environments where the risk of heap overflows and
-			layout control by attackers can usually be
-			frustrated by disabling merging. This will reduce
-			most of the exposure of a heap attack to a single
-			cache (risks via metadata attacks are mostly
-			unchanged). Debug options disable merging on their
-			own.
-			For more information see Documentation/mm/slub.rst.
-
-	slab_max_order=	[MM, SLAB]
-			Determines the maximum allowed order for slabs.
-			A high setting may cause OOMs due to memory
-			fragmentation.  Defaults to 1 for systems with
-			more than 32MB of RAM, 0 otherwise.
-
-	slub_debug[=options[,slabs][;[options[,slabs]]...]	[MM, SLUB]
-			Enabling slub_debug allows one to determine the
+	slab_debug[=options[,slabs][;[options[,slabs]]...]	[MM]
+			Enabling slab_debug allows one to determine the
 			culprit if slab objects become corrupted. Enabling
-			slub_debug can create guard zones around objects and
+			slab_debug can create guard zones around objects and
 			may poison objects when not in use. Also tracks the
 			last alloc / free. For more information see
 			Documentation/mm/slub.rst.
+			(slub_debug legacy name also accepted for now)
 
-	slub_max_order= [MM, SLUB]
+	slab_max_order= [MM]
 			Determines the maximum allowed order for slabs.
 			A high setting may cause OOMs due to memory
 			fragmentation. For more information see
 			Documentation/mm/slub.rst.
+			(slub_max_order legacy name also accepted for now)
+
+	slab_merge	[MM]
+			Enable merging of slabs with similar size when the
+			kernel is built without CONFIG_SLAB_MERGE_DEFAULT.
+			(slub_merge legacy name also accepted for now)
 
-	slub_min_objects=	[MM, SLUB]
+	slab_min_objects=	[MM]
 			The minimum number of objects per slab. SLUB will
-			increase the slab order up to slub_max_order to
+			increase the slab order up to slab_max_order to
 			generate a sufficiently large slab able to contain
 			the number of objects indicated. The higher the number
 			of objects the smaller the overhead of tracking slabs
 			and the less frequently locks need to be acquired.
 			For more information see Documentation/mm/slub.rst.
+			(slub_min_objects legacy name also accepted for now)
 
-	slub_min_order=	[MM, SLUB]
+	slab_min_order=	[MM]
 			Determines the minimum page order for slabs. Must be
-			lower than slub_max_order.
-			For more information see Documentation/mm/slub.rst.
+			lower or equal to slab_max_order. For more information see
+			Documentation/mm/slub.rst.
+			(slub_min_order legacy name also accepted for now)
 
-	slub_merge	[MM, SLUB]
-			Same with slab_merge.
+	slab_nomerge	[MM]
+			Disable merging of slabs with similar size. May be
+			necessary if there is some reason to distinguish
+			allocs to different slabs, especially in hardened
+			environments where the risk of heap overflows and
+			layout control by attackers can usually be
+			frustrated by disabling merging. This will reduce
+			most of the exposure of a heap attack to a single
+			cache (risks via metadata attacks are mostly
+			unchanged). Debug options disable merging on their
+			own.
+			For more information see Documentation/mm/slub.rst.
+			(slub_nomerge legacy name also accepted for now)
 
-	slub_nomerge	[MM, SLUB]
-			Same with slab_nomerge. This is supported for legacy.
-			See slab_nomerge for more information.
+	slram=		[HW,MTD]
 
 	smart2=		[HW]
 			Format: <io1>[,<io2>[,...,<io8>]]