Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757436Ab1EUADR (ORCPT ); Fri, 20 May 2011 20:03:17 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60635 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756419Ab1EUACy (ORCPT ); Fri, 20 May 2011 20:02:54 -0400 From: Vivek Goyal To: linux-kernel@vger.kernel.org, axboe@kernel.dk Cc: dpshah@google.com, namhyung@gmail.com, vgoyal@redhat.com Subject: [PATCH 2/3] cfq-iosched: Make IO merge related stats per cpu Date: Fri, 20 May 2011 20:02:46 -0400 Message-Id: <1305936167-8932-3-git-send-email-vgoyal@redhat.com> In-Reply-To: <1305936167-8932-1-git-send-email-vgoyal@redhat.com> References: <1305936167-8932-1-git-send-email-vgoyal@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2746 Lines: 84 Make BLKIO_STAT_MERGED per cpu hence gettring rid of need of taking blkg->stats_lock. Signed-off-by: Vivek Goyal --- block/blk-cgroup.c | 22 +++++++++++++++++----- block/blk-cgroup.h | 4 ++-- 2 files changed, 19 insertions(+), 7 deletions(-) diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index e41cc6f..07371cf 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -441,15 +441,27 @@ void blkiocg_update_completion_stats(struct blkio_group *blkg, } EXPORT_SYMBOL_GPL(blkiocg_update_completion_stats); +/* Merged stats are per cpu. */ void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction, bool sync) { + struct blkio_group_stats_cpu *stats_cpu; unsigned long flags; - spin_lock_irqsave(&blkg->stats_lock, flags); - blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_MERGED], 1, direction, - sync); - spin_unlock_irqrestore(&blkg->stats_lock, flags); + /* + * Disabling interrupts to provide mutual exclusion between two + * writes on same cpu. It probably is not needed for 64bit. Not + * optimizing that case yet. + */ + local_irq_save(flags); + + stats_cpu = this_cpu_ptr(blkg->stats_cpu); + + u64_stats_update_begin(&stats_cpu->syncp); + blkio_add_stat(stats_cpu->stat_arr_cpu[BLKIO_STAT_CPU_MERGED], 1, + direction, sync); + u64_stats_update_end(&stats_cpu->syncp); + local_irq_restore(flags); } EXPORT_SYMBOL_GPL(blkiocg_update_io_merged_stats); @@ -1244,7 +1256,7 @@ static int blkiocg_file_read_map(struct cgroup *cgrp, struct cftype *cft, BLKIO_STAT_WAIT_TIME, 1, 0); case BLKIO_PROP_io_merged: return blkio_read_blkg_stats(blkcg, cft, cb, - BLKIO_STAT_MERGED, 1, 0); + BLKIO_STAT_CPU_MERGED, 1, 1); case BLKIO_PROP_io_queued: return blkio_read_blkg_stats(blkcg, cft, cb, BLKIO_STAT_QUEUED, 1, 0); diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h index 2622267..a71d290 100644 --- a/block/blk-cgroup.h +++ b/block/blk-cgroup.h @@ -39,8 +39,6 @@ enum stat_type { BLKIO_STAT_SERVICE_TIME = 0, /* Total time spent waiting in scheduler queue in ns */ BLKIO_STAT_WAIT_TIME, - /* Number of IOs merged */ - BLKIO_STAT_MERGED, /* Number of IOs queued up */ BLKIO_STAT_QUEUED, /* All the single valued stats go below this */ @@ -63,6 +61,8 @@ enum stat_type_cpu { BLKIO_STAT_CPU_SERVICE_BYTES, /* Total IOs serviced, post merge */ BLKIO_STAT_CPU_SERVICED, + /* Number of IOs merged */ + BLKIO_STAT_CPU_MERGED, BLKIO_STAT_CPU_NR }; -- 1.7.4.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/