Hello, (The posting yesterday went out w/o lkml cc'd and old head message, resending w/ Vivek's suggestions applied. Sorry about the noise.) This is the second take of "implement per-blkg request allocation" patchset. Changes from the last take[L] are * 0001-fix-blkg_alloc-failure-path patch is separated from this series and merged to block/for-linus. * Updated patches posted incrementally merged into the series. * Rebased on top of the current block/for-linus. * Documentation/block/queue-sysfs.txt updated to note that nr_requests is per-blkcg. * Acked/Reviewed-by's added. The original description follows. Currently block layer shares a single request_list (@q->rq) for all IOs regardless of their blkcg associations. This means that once the shared pool is exhausted, blkcg limits don't mean much. Whoever grabs the requests being freed the first grabs the next IO slot. This priority inversion can be easily demonstrated by creating a blkio cgroup w/ very low weight, put a program which can issue a lot of random direct IOs there and running a sequential IO from a different cgroup. As soon as the request pool is used up, the sequential IO bandwidth crashes. This patchset implements per-blkg request allocation so that each blkcg-request_queue pair has its own request pool to allocate from. This isolates different blkcgs in terms of request allocation. Most changes are straight-forward; unfortunately, bdi isn't blkcg-aware yet so it currently just propagates the congestion state from root blkcg. As writeback currently is always on the root blkcg, this kinda works for write congestion but readahead may behave non-optimally under congestion for now. This needs to be improved but the situation is still way better than blkcg completely collapsing. 0001-blkcg-__blkg_lookup_create-doesn-t-need-radix-preloa.patch 0002-blkcg-make-root-blkcg-allocation-use-GFP_KERNEL.patch 0003-mempool-add-gfp_mask-to-mempool_create_node.patch 0004-block-drop-custom-queue-draining-used-by-scsi_transp.patch 0005-block-refactor-get_request-_wait.patch 0006-block-allocate-io_context-upfront.patch 0007-blkcg-inline-bio_blkcg-and-friends.patch 0008-block-add-q-nr_rqs-and-move-q-rq.elvpriv-to-q-nr_rqs.patch 0009-block-prepare-for-multiple-request_lists.patch 0010-blkcg-implement-per-blkg-request-allocation.patch 0001-0002 are misc preps. 0003 adds @gfp_mask to mempool_create_node(). This is necessary because blkg allocation is on the IO path and now blkg contains mempool for request_list. Note that blkg allocation failure doesn't lead to catastrophic failure. It just hinders blkcg enforcement. 0004 drops custom queue draining which I dont't think is necessary and hinders with further updates. 0005-0009 are prep patches and 0010 implements per-blkg request allocation. This patchset is on top of the current block/for-linus - 9b2ea86bc9e "blkcg: fix blkg_alloc() failure path" and is also available in the following git branch. git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc.git blkcg-rl Documentation/block/queue-sysfs.txt | 7 + block/blk-cgroup.c | 139 ++++++++++++++++--------- block/blk-cgroup.h | 121 +++++++++++++++++++++ block/blk-core.c | 200 ++++++++++++++++++------------------ block/blk-sysfs.c | 34 +++--- block/blk-throttle.c | 3 block/blk.h | 3 block/bsg-lib.c | 53 --------- drivers/scsi/scsi_transport_fc.c | 38 ------ drivers/scsi/scsi_transport_iscsi.c | 2 include/linux/blkdev.h | 53 +++++---- include/linux/bsg-lib.h | 1 include/linux/mempool.h | 3 mm/mempool.c | 12 +- 14 files changed, 382 insertions(+), 287 deletions(-) Thanks. -- tejun [L] http://thread.gmane.org/gmane.linux.kernel.containers/23159 _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers
