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@xxxxxxxx> Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@xxxxxxxxxx>
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