From 3df1cccdfb3fab6aa9176beb655d802eb384eabc Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Tue, 18 Oct 2011 22:09:28 -0700 Subject: slab: introduce slab_max_order kernel parameter Introduce new slab_max_order kernel parameter which is the equivalent of slub_max_order. For immediate purposes, allows users to override the heuristic that sets the max order to 1 by default if they have more than 32MB of RAM. This may result in page allocation failures if there is substantial fragmentation. Another usecase would be to increase the max order for better performance. Acked-by: Christoph Lameter Signed-off-by: David Rientjes Signed-off-by: Pekka Enberg --- Documentation/kernel-parameters.txt | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index a0c5c5f4fce6..b21093eabef1 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2362,6 +2362,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted. slram= [HW,MTD] + 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]] [MM, SLUB] Enabling slub_debug allows one to determine the culprit if slab objects become corrupted. Enabling -- cgit 1.4.1 From 25f4379b8c79066c4be0e5995f37f5265733b801 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 22 Nov 2011 06:59:09 +0100 Subject: slub: fix slub_max_order Documentation slub_max_order default is 3 (aka PAGE_ALLOC_COSTLY_ORDER), not 1 Acked-by: David Rientjes Acked-by: Christoph Lameter Signed-off-by: Eric Dumazet Signed-off-by: Pekka Enberg --- Documentation/vm/slub.txt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/vm/slub.txt b/Documentation/vm/slub.txt index f464f47bc60d..2acdda9601b0 100644 --- a/Documentation/vm/slub.txt +++ b/Documentation/vm/slub.txt @@ -117,7 +117,7 @@ can be influenced by kernel parameters: slub_min_objects=x (default 4) slub_min_order=x (default 0) -slub_max_order=x (default 1) +slub_max_order=x (default 3 (PAGE_ALLOC_COSTLY_ORDER)) slub_min_objects allows to specify how many objects must at least fit into one slab in order for the allocation order to be acceptable. -- cgit 1.4.1