From: Rik van Riel <riel@redhat.com>
To: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: mhocko@suse.cz, akpm@linux-foundation.org, mgorman@suse.de,
kamezawa.hiroyu@jp.fujitsu.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] COMPACTION: bugfix of improper cache flush in MIGRATION code.
Date: Thu, 09 May 2013 10:38:42 -0400 [thread overview]
Message-ID: <518BB4F2.2040704@redhat.com> (raw)
In-Reply-To: <20130509001821.15951.98705.stgit@linux-yegoshin>
On 05/08/2013 08:18 PM, Leonid Yegoshin wrote:
> Page 'new' during MIGRATION can't be flushed by flush_cache_page().
> Using flush_cache_page(vma, addr, pfn) is justified only if
> page is already placed in process page table, and that is done right
> after flush_cache_page(). But without it the arch function has
> no knowledge of process PTE and does nothing.
>
> Besides that, flush_cache_page() flushes an application cache,
> kernel has a different page virtual address and dirtied it.
>
> Replace it with flush_dcache_page(new) which is a proper usage.
>
> Old page is flushed in try_to_unmap_one() before MIGRATION.
>
> This bug takes place in Sead3 board with M14Kc MIPS CPU without
> cache aliasing (but Harvard arch - separate I and D cache)
> in tight memory environment (128MB) each 1-3days on SOAK test.
> It fails in cc1 during kernel build (SIGILL, SIGBUS, SIGSEG) if
> CONFIG_COMPACTION is switched ON.
Good catch!
> Author: Leonid Yegoshin <yegoshin@mips.com>
> Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Acked-by: Rik van Riel <riel@redhat.com>
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WARNING: multiple messages have this Message-ID (diff)
From: Rik van Riel <riel@redhat.com>
To: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: mhocko@suse.cz, akpm@linux-foundation.org, mgorman@suse.de,
kamezawa.hiroyu@jp.fujitsu.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] COMPACTION: bugfix of improper cache flush in MIGRATION code.
Date: Thu, 09 May 2013 10:38:42 -0400 [thread overview]
Message-ID: <518BB4F2.2040704@redhat.com> (raw)
In-Reply-To: <20130509001821.15951.98705.stgit@linux-yegoshin>
On 05/08/2013 08:18 PM, Leonid Yegoshin wrote:
> Page 'new' during MIGRATION can't be flushed by flush_cache_page().
> Using flush_cache_page(vma, addr, pfn) is justified only if
> page is already placed in process page table, and that is done right
> after flush_cache_page(). But without it the arch function has
> no knowledge of process PTE and does nothing.
>
> Besides that, flush_cache_page() flushes an application cache,
> kernel has a different page virtual address and dirtied it.
>
> Replace it with flush_dcache_page(new) which is a proper usage.
>
> Old page is flushed in try_to_unmap_one() before MIGRATION.
>
> This bug takes place in Sead3 board with M14Kc MIPS CPU without
> cache aliasing (but Harvard arch - separate I and D cache)
> in tight memory environment (128MB) each 1-3days on SOAK test.
> It fails in cc1 during kernel build (SIGILL, SIGBUS, SIGSEG) if
> CONFIG_COMPACTION is switched ON.
Good catch!
> Author: Leonid Yegoshin <yegoshin@mips.com>
> Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Acked-by: Rik van Riel <riel@redhat.com>
next prev parent reply other threads:[~2013-05-09 14:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-09 0:18 [PATCH] COMPACTION: bugfix of improper cache flush in MIGRATION code Leonid Yegoshin
2013-05-09 0:18 ` Leonid Yegoshin
2013-05-09 14:38 ` Rik van Riel [this message]
2013-05-09 14:38 ` Rik van Riel
2013-05-10 9:52 ` Mel Gorman
2013-05-10 9:52 ` Mel Gorman
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