Messages in this thread | | | Date | Thu, 09 May 2013 10:38:42 -0400 | From | Rik van Riel <> | Subject | Re: [PATCH] COMPACTION: bugfix of improper cache flush in MIGRATION code. |
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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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