On Tue, Apr 28, 2009 at 10:43:51AM +0200, Andrea Righi wrote: > This is the core of the io-throttle kernel infrastructure. It creates > the basic interfaces to the cgroup subsystem and implements the I/O > measurement and throttling functionality.
Subject: io-throttle: correctly throttle O_DIRECT reads There's a bug in the latest io-throttle patchset: the IO generated by O_DIRECT reads is correctly accounted, but tasks doing direct IO are not correctly throttled. The following fix apply the correct behaviour, throttling the tasks that are doing O_DIRECT reads directly, instead of delaying their IO requests. [ This patch must be applied on top of io-throttle v15 ] Signed-off-by: Andrea Righi <[email protected]> --- block/blk-io-throttle.c | 21 ++++++++++++--------- 1 files changed, 12 insertions(+), 9 deletions(-) diff --git a/block/blk-io-throttle.c b/block/blk-io-throttle.c index 380a21a..8dc2c93 100644 --- a/block/blk-io-throttle.c +++ b/block/blk-io-throttle.c @@ -803,12 +803,21 @@ cgroup_io_throttle(struct bio *bio, struct block_device *bdev, ssize_t bytes) * cgroup. If they're different we're doing writeback IO and we can't * throttle the current task directly. */ - if (!is_in_dio()) + if (!is_in_dio()) { + /* + * We're not doing O_DIRECT: find the source of this IO + * request. + */ iot = get_iothrottle_from_bio(bio); + } rcu_read_lock(); curr_iot = task_to_iothrottle(current); - if (curr_iot != iot) { - css_get(&curr_iot->css); + if (iot == NULL) { + /* IO occurs in the same context of the current task */ + iot = curr_iot; + css_get(&iot->css); + } + if (iot != curr_iot) { /* * IO occurs in a different context of the current task * (writeback IO). @@ -819,10 +828,6 @@ cgroup_io_throttle(struct bio *bio, struct block_device *bdev, ssize_t bytes) */ can_sleep = 0; } - if (iot == NULL) { - /* IO occurs in the same context of the current task */ - iot = curr_iot; - } /* Apply IO throttling */ iothrottle_evaluate_sleep(&s, iot, bdev, bytes); sleep = max(s.bw_sleep, s.iops_sleep); @@ -831,8 +836,6 @@ cgroup_io_throttle(struct bio *bio, struct block_device *bdev, ssize_t bytes) if (unlikely(sleep && can_sleep)) iothrottle_acct_stat(iot, bdev, type, sleep); css_put(&iot->css); - if (curr_iot != iot) - css_put(&curr_iot->css); rcu_read_unlock(); if (unlikely(sleep && can_sleep)) { /* Throttle the current task directly */ _______________________________________________ Containers mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
