Re: [patch v3] swap: virtual swap readahead

Jesse Barnes
2009-06-10T17:25:42Z

On Wed, 10 Jun 2009 04:32:14 -0700
"Wu, Fengguang" <fengguang.wu@intel.com> wrote:

> On Wed, Jun 10, 2009 at 06:05:14PM +0800, Peter Zijlstra wrote:
> > On Wed, 2009-06-10 at 17:59 +0800, Wu Fengguang wrote:
> > > On Wed, Jun 10, 2009 at 05:42:56PM +0800, Peter Zijlstra wrote:
> > > > On Wed, 2009-06-10 at 16:56 +0800, Wu Fengguang wrote:
> > > > >
> > > > > Yes it worked! But then I run into page allocation failures:
> > > > >
> > > > > [ 340.639803] Xorg: page allocation failure. order:4,
> > > > > mode:0x40d0 [ 340.645744] Pid: 3258, comm: Xorg Not tainted
> > > > > 2.6.30-rc8-mm1 #303 [ 340.651839] Call Trace:
> > > > > [ 340.654289] [<ffffffff810c8204>]
> > > > > __alloc_pages_nodemask+0x344/0x6c0 [ 340.660645]
> > > > > [<ffffffff810f7489>] __slab_alloc_page+0xb9/0x3b0
> > > > > [ 340.666472] [<ffffffff810f8608>] __kmalloc+0x198/0x250
> > > > > [ 340.671786] [<ffffffffa014bf9f>] ?
> > > > > i915_gem_execbuffer+0x17f/0x11e0 [i915] [ 340.678746]
> > > > > [<ffffffffa014bf9f>] i915_gem_execbuffer+0x17f/0x11e0 [i915]
> > > >
> > > > Jesse Barnes had a patch to add a vmalloc fallback to those
> > > > largish kms allocs.
> > > >
> > > > But order-4 allocs failing isn't really strange, but it might
> > > > indicate this patch fragments stuff sooner, although I've seen
> > > > these particular failues before.
> > >
> > > Thanks for the tip. Where is it? I'd like to try it out :)
> >
> > commit 8e7d2b2c6ecd3c21a54b877eae3d5be48292e6b5
> > Author: Jesse Barnes <jbarnes@virtuousgeek.org>
> > Date: Fri May 8 16:13:25 2009 -0700
> >
> > drm/i915: allocate large pointer arrays with vmalloc
>
> Thanks! It is already in the -mm tree, but it missed on conversion :)
>
> I'll retry with this patch tomorrow.
>
> Thanks,
> Fengguang
> ---
>
> diff --git a/drivers/gpu/drm/i915/i915_gem.c
> b/drivers/gpu/drm/i915/i915_gem.c index 39f5c65..7132dbe 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -3230,8 +3230,8 @@ i915_gem_execbuffer(struct drm_device *dev,
> void *data, }
>
> if (args->num_cliprects != 0) {
> - cliprects = drm_calloc(args->num_cliprects,
> sizeof(*cliprects),
> - DRM_MEM_DRIVER);
> + cliprects = drm_calloc_large(args->num_cliprects,
> + sizeof(*cliprects));
> if (cliprects == NULL)
> goto pre_mutex_err;
>
> @@ -3474,8 +3474,7 @@ err:
> pre_mutex_err:
> drm_free_large(object_list);
> drm_free_large(exec_list);
> - drm_free(cliprects, sizeof(*cliprects) * args->num_cliprects,
> - DRM_MEM_DRIVER);
> + drm_free_large(cliprects);
>
> return ret;
> }

Kristian posted a fix to my drm_calloc_large function as well; one of
the size checks in drm_calloc_large (the one which decides whether to
use kmalloc or vmalloc) was just checking size instead of size * num,
so you may be hitting that.

Jesse