summaryrefslogtreecommitdiff
path: root/block/blk-settings.c
diff options
context:
space:
mode:
authorVivek Goyal <vgoyal@redhat.com>2009-12-16 17:52:59 -0500
committerJens Axboe <jens.axboe@oracle.com>2009-12-18 12:40:21 +0100
commit65b32a573eefa1cdd3cbe5ea59326308e6c3b9ad (patch)
treebdcca029d184056ffc9eab0a9c0b95cdf123c9fb /block/blk-settings.c
parentfb104db41e6e006c85ce1097f372cd1e10c1755c (diff)
cfq-iosched: Remove prio_change logic for workload selection
o CFQ now internally divides cfq queues in therr workload categories. sync-idle, sync-noidle and async. Which workload to run depends primarily on rb_key offset across three service trees. Which is a combination of mulitiple things including what time queue got queued on the service tree. There is one exception though. That is if we switched the prio class, say we served some RT tasks and again started serving BE class, then with-in BE class we always started with sync-noidle workload irrespective of rb_key offset in service trees. This can provide better latencies for sync-noidle workload in the presence of RT tasks. o This patch gets rid of that exception and which workload to run with-in class always depends on lowest rb_key across service trees. The reason being that now we have multiple BE class groups and if we always switch to sync-noidle workload with-in group, we can potentially starve a sync-idle workload with-in group. Same is true for async workload which will be in root group. Also the workload-switching with-in group will become very unpredictable as it now depends whether some RT workload was running in the system or not. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com> Acked-by: Corrado Zoccolo <czoccolo@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blk-settings.c')
0 files changed, 0 insertions, 0 deletions