• Jens Axboe's avatar
    [PATCH] Kill PF_SYNCWRITE flag · b31dc66a
    Jens Axboe authored
    A process flag to indicate whether we are doing sync io is incredibly
    ugly. It also causes performance problems when one does a lot of async
    io and then proceeds to sync it. Part of the io will go out as async,
    and the other part as sync. This causes a disconnect between the
    previously submitted io and the synced io. For io schedulers such as CFQ,
    this will cause us lost merges and suboptimal behaviour in scheduling.
    Remove PF_SYNCWRITE completely from the fsync/msync paths, and let
    the O_DIRECT path just directly indicate that the writes are sync
    by using WRITE_SYNC instead.
    Signed-off-by: default avatarJens Axboe <axboe@suse.de>
ll_rw_blk.c 99.3 KB