mm compaction: fix of improper cache flush in migration code
Page 'new' during MIGRATION can't be flushed with flush_cache_page().
Using flush_cache_page(vma, addr, pfn) is justified only if the 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 page, but
the kernel has a different page virtual address and dirtied it.
Replace it with flush_dcache_page(new) which is the proper usage.
The 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
Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: Leonid Yegoshin <firstname.lastname@example.org>
Acked-by: Rik van Riel <email@example.com>
Cc: Michal Hocko <firstname.lastname@example.org>
Acked-by: Mel Gorman <email@example.com>
Cc: Ralf Baechle <firstname.lastname@example.org>
Cc: Russell King <email@example.com>
Cc: David Miller <firstname.lastname@example.org>
Signed-off-by: Andrew Morton <email@example.com>
Signed-off-by: Linus Torvalds <firstname.lastname@example.org>
1 file changed