From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 24 Jul 2007 12:36:59 -0700 (PDT) From: Christoph Lameter Subject: Re: [PATCH] add __GFP_ZERO to GFP_LEVEL_MASK In-Reply-To: <20070724122542.d4ac734a.akpm@linux-foundation.org> Message-ID: References: <1185185020.8197.11.camel@twins> <20070723112143.GB19437@skynet.ie> <1185190711.8197.15.camel@twins> <1185256869.8197.27.camel@twins> <1185261894.8197.33.camel@twins> <20070724120751.401bcbcb@schroedinger.engr.sgi.com> <20070724122542.d4ac734a.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: Peter Zijlstra , Mel Gorman , Linus Torvalds , linux-kernel , Daniel Phillips , linux-mm List-ID: On Tue, 24 Jul 2007, Andrew Morton wrote: > > __GFP_MOVABLE The movability of a slab is determined by the > > options specified at kmem_cache_create time. If this is > > specified at kmalloc time then we will have some random > > slabs movable and others not. > > Yes, they seem inappropriate. Especially the first two. The third one would randomize __GFP_MOVABLE allocs from the page allocator since one __GFP_MOVABLE alloc may allocate a slab that is then used for !__GFP_MOVABLE allocs. Maybe something like this? Note that we may get into some churn here since slab allocations that any of these flags will BUG. GFP_LEVEL_MASK: Remove __GFP_COLD, __GFP_COMP and __GFPMOVABLE Add an explanation for the GFP_LEVEL_MASK and remove the flags that should not be passed through derived allocators. Signed-off-by: Christoph Lameter Index: linux-2.6/include/linux/gfp.h =================================================================== --- linux-2.6.orig/include/linux/gfp.h 2007-07-24 12:31:04.000000000 -0700 +++ linux-2.6/include/linux/gfp.h 2007-07-24 12:32:50.000000000 -0700 @@ -53,12 +53,15 @@ struct vm_area_struct; #define __GFP_BITS_SHIFT 20 /* Room for 20 __GFP_FOO bits */ #define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1)) -/* if you forget to add the bitmask here kernel will crash, period */ +/* + * GFP_LEVEL_MASK is used to filter out flags to be passed on to the + * page allocator in derived allocators such as slab allocators and + * vmalloc. It should not contain flags that are to be handled by the + * derived allocators themselves. + */ #define GFP_LEVEL_MASK (__GFP_WAIT|__GFP_HIGH|__GFP_IO|__GFP_FS| \ - __GFP_COLD|__GFP_NOWARN|__GFP_REPEAT| \ - __GFP_NOFAIL|__GFP_NORETRY|__GFP_COMP| \ - __GFP_NOMEMALLOC|__GFP_HARDWALL|__GFP_THISNODE| \ - __GFP_MOVABLE) + __GFP_NOWARN|__GFP_REPEAT|__GFP_NOFAIL|__GFP_NORETRY| \ + __GFP_NOMEMALLOC|__GFP_HARDWALL|__GFP_THISNODE| __GFP_MOVABLE) /* This equals 0, but use constants in case they ever change */ #define GFP_NOWAIT (GFP_ATOMIC & ~__GFP_HIGH) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org