4.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mark Salyzyn <salyzyn@xxxxxxxxxxx> commit 569ba74a7ba69f46ce2950bf085b37fea2408385 upstream. This is the arm64 portion of commit 45cac65b0fcd ("readahead: fault retry breaks mmap file read random detection"), which was absent from the initial port and has since gone unnoticed. The original commit says: > .fault now can retry. The retry can break state machine of .fault. In > filemap_fault, if page is miss, ra->mmap_miss is increased. In the second > try, since the page is in page cache now, ra->mmap_miss is decreased. And > these are done in one fault, so we can't detect random mmap file access. > > Add a new flag to indicate .fault is tried once. In the second try, skip > ra->mmap_miss decreasing. The filemap_fault state machine is ok with it. With this change, Mark reports that: > Random read improves by 250%, sequential read improves by 40%, and > random write by 400% to an eMMC device with dm crypto wrapped around it. Cc: Shaohua Li <shli@xxxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxx> Cc: Wu Fengguang <fengguang.wu@xxxxxxxxx> Signed-off-by: Mark Salyzyn <salyzyn@xxxxxxxxxxx> Signed-off-by: Riley Andrews <riandrews@xxxxxxxxxxx> Signed-off-by: Will Deacon <will.deacon@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/arm64/mm/fault.c | 1 + 1 file changed, 1 insertion(+) --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -279,6 +279,7 @@ retry: * starvation. */ mm_flags &= ~FAULT_FLAG_ALLOW_RETRY; + mm_flags |= FAULT_FLAG_TRIED; goto retry; } } -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html