Messages in this thread Patch in this message | | | Date | Fri, 02 Jul 2010 01:34:52 +0300 | From | "M. Vefa Bicakci" <> | Subject | Re: [Intel-gfx] [PATCH] drm/i915: Selectively enable self-reclaim |
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On 01/07/10 04:24 AM, Linus Torvalds wrote: > On Wed, Jun 30, 2010 at 4:07 PM, Linus Torvalds > <torvalds@linux-foundation.org> wrote: >> >> That commit changes the page cache allocation to use >> >> + mapping_gfp_mask (mapping) | >> + __GFP_COLD | >> + gfpmask); >> >> if I read it right. And the default mapping_gfp_mask() is >> GFP_HIGHUSER_MOVABLE, so I think you get all of >> (__GFP_WAIT | __GFP_IO | __GFP_FS | __GFP_HARDWALL | __GFP_HIGHMEM) >> set by default. > > .. and then I left out the one flag I _meant_ to have there, namely > __GFP_MOVABLE. > >> The old code didn't just play games with ~__GFP_NORETRY and change >> that at runtime (which was buggy - no locking, no protection, no >> nothing), it also initialized the gfp mask. And that code also got >> removed: > > In fact, I don't really see why we should use that mapping_gfp_mask() > at all, since all allocations should be going through that > i915_gem_object_get_pages() function anyway. So why not just change > that function to ignore the default gfp mask for the mapping, and just > use the mask that the o915 driver wants? > > Btw, why did it want to mark the pages reclaimable? > > Anyway, what I'm suggesting somebody who sees this test is just > something like the patch below (whitespace-damage - I'm cutting and > pasting, it's a trivial one-liner). Does this change any behavior? > Vefa? > > Linus
Dear Linus,
I made the code change you documented below to a vanilla 2.6.34 tree, compiled it and tested hibernate/thaw cycles. In total, I tested 16 cycles, with 8 consecutive cycles in one installation (Debian Sid) and 8 consecutive cycles in another one (Fedora 13). For every cycle, I tried to run "old" and "new" programs, in terms of whether they were run in previous cycles. I tried a few extra cycles with uswsusp as well.
Based on my testing, I am happy to report that the change you suggest fixes the "memory corruption (segfaults) after thaw" issue for me. I can't thank you enough times for this.
Now, the obligatory question: Could we have this fix applied to 2.6.32, 2.6.33 and 2.6.34 ?
Thanks a lot again!
M. Vefa Bicakci
--- linux-2.6.34/drivers/gpu/drm/i915/i915_gem.c.orig 2010-07-01 17:47:30.000000000 +0000 +++ linux-2.6.34/drivers/gpu/drm/i915/i915_gem.c 2010-07-01 17:54:03.000000000 +0000 @@ -2312,7 +2312,7 @@ mapping = inode->i_mapping; for (i = 0; i < page_count; i++) { page = read_cache_page_gfp(mapping, i, - mapping_gfp_mask (mapping) | + __GFP_HIGHMEM | __GFP_COLD | gfpmask); if (IS_ERR(page))
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