Re: [Bug #13058] First hibernation attempt fails

Andrew Morton
2009-04-20T20:04:12Z

On Mon, 20 Apr 2009 21:53:06 +0200
Pavel Machek <pavel-+ZI9xUNit7I@public.gmane.org> 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 */
_