linux-kernel - Re: [Bug #13058] First hibernation attempt fails

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Message-Id: <20090420130412.bc337673.akpm@linux-foundation.org>
Date:	Mon, 20 Apr 2009 13:04:12 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Pavel Machek <pavel@....cz>
Cc:	torvalds@...ux-foundation.org, jens.axboe@...cle.com,
	alan-jenkins@...fmail.co.uk, rjw@...k.pl,
	linux-kernel@...r.kernel.org, kernel-testers@...r.kernel.org
Subject: Re: [Bug #13058] First hibernation attempt fails

On Mon, 20 Apr 2009 21:53:06 +0200
Pavel Machek <pavel@....cz> wrote:

> > 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 out 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...


diff -puN mm/page_alloc.c~a mm/page_alloc.c
--- a/mm/page_alloc.c~a
+++ a/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;
 		}
diff -puN include/linux/gfp.h~a include/linux/gfp.h
--- a/include/linux/gfp.h~a
+++ a/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 */
 #define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1))
 
 /* This equals 0, but use constants in case they ever change */
_

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