From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wu Fengguang Subject: Re: [PATCH 1/4] mm: Add __GFP_NO_OOM_KILL flag Date: Sun, 3 May 2009 19:54:50 +0800 Message-ID: <20090503115450.GB9661@localhost> References: <20090502104947.2720f173.akpm@linux-foundation.org> <200905030220.57933.rjw@sisk.pl> <200905030222.07360.rjw@sisk.pl> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <200905030222.07360.rjw-KKrjLPT3xs0@public.gmane.org> Sender: kernel-testers-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: "Rafael J. Wysocki" Cc: Andrew Morton , pavel-+ZI9xUNit7I@public.gmane.org, torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, jens.axboe-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, alan-jenkins-cCz0Lq7MMjm9FHfhHBbuYA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kernel-testers-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-pm-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org On Sun, May 03, 2009 at 02:22:06AM +0200, Rafael J. Wysocki wrote: > From: Andrew Morton > > > > Remind me: why can't we just allocate N pages at suspend-time? > > > > We need half of memory free. The reason we can't "just allocate" is > > probably OOM killer; but my memories are quite weak :-(. > > hm. You'd think that with our splendid range of __GFP_foo falgs, there > would be some combo which would suit this requirement but I can't > immediately spot one. > > We can always add another I guess. Something like... > > Signed-off-by: Rafael J. Wysocki > --- > include/linux/gfp.h | 3 ++- > mm/page_alloc.c | 3 ++- > 2 files changed, 4 insertions(+), 2 deletions(-) > > Index: linux-2.6/mm/page_alloc.c > =================================================================== > --- linux-2.6.orig/mm/page_alloc.c > +++ linux-2.6/mm/page_alloc.c > @@ -1620,7 +1620,8 @@ nofail_alloc: > } > > /* The OOM killer will not help higher order allocs so fail */ > - if (order > PAGE_ALLOC_COSTLY_ORDER) { > + if (order > PAGE_ALLOC_COSTLY_ORDER || > + (gfp_mask & __GFP_NO_OOM_KILL)) { > clear_zonelist_oom(zonelist, gfp_mask); > goto nopage; > } > Index: linux-2.6/include/linux/gfp.h > =================================================================== > --- linux-2.6.orig/include/linux/gfp.h > +++ linux-2.6/include/linux/gfp.h > @@ -51,8 +51,9 @@ struct vm_area_struct; > #define __GFP_THISNODE ((__force gfp_t)0x40000u)/* No fallback, no policies */ > #define __GFP_RECLAIMABLE ((__force gfp_t)0x80000u) /* Page is reclaimable */ > #define __GFP_MOVABLE ((__force gfp_t)0x100000u) /* Page is movable */ > +#define __GFP_NO_OOM_KILL ((__force gfp_t)0x200000u) /* Don't invoke out_of_memory() */ > > -#define __GFP_BITS_SHIFT 21 /* Room for 21 __GFP_FOO bits */ > +#define __GFP_BITS_SHIFT 22 /* Number of__GFP_FOO bits */ ^ missed a white space :)