Re: Userland swsusp failure (mm-related)
From: Rafael J. Wysocki
Date: Tue Apr 11 2006 - 17:34:51 EST
Hi,
On Sunday 09 April 2006 03:51, Nick Piggin wrote:
> Rafael J. Wysocki wrote:
> >>>Well, it looks like we didn't free enough RAM for suspend in this case.
> >>>Unfortunately we were below the min watermark for ZONE_NORMAL and
> >>>we tried to allocate with GFP_ATOMIC (Nick, shouldn't we fall back to
> >>>ZONE_DMA in this case?).
> >>>
> >>>I think we can safely ignore the watermarks in swsusp, so probably
> >>>we can set PF_MEMALLOC for the current task temporarily and reset
> >>>it when we have allocated memory. Pavel, what do you think?
> >>
> >>Seems little hacky but okay to me.
> >>
> >>Should not fixing "how much to free" computation to free a bit more be
> >>enough to handle this?
> >
> >
> > Yes, but in that case we'll leave some memory unused. ;-)
> >
>
> Probably doesn't fall back to ZONE_DMA because of lowmem reserve.
> Yes, PF_MEMALLOC sounds like it might do what you want. A little
> hackish perhaps, but better than putting swsusp special cases
> into page_alloc.c.
The appended patch contains the changes I'd like to make. Pavel, is that
acceptable?
Rafael
---
kernel/power/snapshot.c | 10 ++++++++--
1 files changed, 8 insertions(+), 2 deletions(-)
Index: linux-2.6.17-rc1-mm2/kernel/power/snapshot.c
===================================================================
--- linux-2.6.17-rc1-mm2.orig/kernel/power/snapshot.c 2006-04-08 21:29:55.000000000 +0200
+++ linux-2.6.17-rc1-mm2/kernel/power/snapshot.c 2006-04-11 22:09:28.000000000 +0200
@@ -461,17 +461,23 @@ static struct pbe *swsusp_alloc(unsigned
{
struct pbe *pblist;
+ /* We don't want to be affected by zone watermarks etc. */
+ current->flags |= PF_MEMALLOC;
+
if (!(pblist = alloc_pagedir(nr_pages, GFP_ATOMIC | __GFP_COLD, 0))) {
printk(KERN_ERR "suspend: Allocating pagedir failed.\n");
- return NULL;
+ goto out;
}
if (alloc_data_pages(pblist, GFP_ATOMIC | __GFP_COLD, 0)) {
printk(KERN_ERR "suspend: Allocating image pages failed.\n");
swsusp_free();
- return NULL;
+ pblist = NULL;
}
+out:
+ current->flags &= ~PF_MEMALLOC;
+
return pblist;
}
-
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