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由 Mark Salyzyn 提交于
This is the arm64 portion of commit 45cac65b ("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@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: NMark Salyzyn <salyzyn@android.com> Signed-off-by: NRiley Andrews <riandrews@android.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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