From 38535201633077cbaf8b32886b5e3005b36c9024 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 25 Apr 2014 02:32:53 -0700 Subject: [PATCH] blk-mq: respect rq_affinity The blk-mq code is using it's own version of the I/O completion affinity tunables, which causes a few issues: - the rq_affinity sysfs file doesn't work for blk-mq devices, even if it still is present, thus breaking existing tuning setups. - the rq_affinity = 1 mode, which is the defauly for legacy request based drivers isn't implemented at all. - blk-mq drivers don't implement any completion affinity with the default flag settings. This patches removes the blk-mq ipi_redirect flag and sysfs file, as well as the internal BLK_MQ_F_SHOULD_IPI flag and replaces it with code that respects the queue-wide rq_affinity flags and also implements the rq_affinity = 1 mode. This means I/O completion affinity can now only be tuned block-queue wide instead of per context, which seems more sensible to me anyway. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- block/blk-mq-sysfs.c | 42 ------------------------------------------ block/blk-mq.c | 8 ++++++-- block/blk-mq.h | 1 - include/linux/blk-mq.h | 1 - 4 files changed, 6 insertions(+), 46 deletions(-) diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c index 9176a6984857..8145b5b25b4b 100644 --- a/block/blk-mq-sysfs.c +++ b/block/blk-mq-sysfs.c @@ -203,42 +203,6 @@ static ssize_t blk_mq_hw_sysfs_rq_list_show(struct blk_mq_hw_ctx *hctx, return ret; } -static ssize_t blk_mq_hw_sysfs_ipi_show(struct blk_mq_hw_ctx *hctx, char *page) -{ - ssize_t ret; - - spin_lock(&hctx->lock); - ret = sprintf(page, "%u\n", !!(hctx->flags & BLK_MQ_F_SHOULD_IPI)); - spin_unlock(&hctx->lock); - - return ret; -} - -static ssize_t blk_mq_hw_sysfs_ipi_store(struct blk_mq_hw_ctx *hctx, - const char *page, size_t len) -{ - struct blk_mq_ctx *ctx; - unsigned long ret; - unsigned int i; - - if (kstrtoul(page, 10, &ret)) { - pr_err("blk-mq-sysfs: invalid input '%s'\n", page); - return -EINVAL; - } - - spin_lock(&hctx->lock); - if (ret) - hctx->flags |= BLK_MQ_F_SHOULD_IPI; - else - hctx->flags &= ~BLK_MQ_F_SHOULD_IPI; - spin_unlock(&hctx->lock); - - hctx_for_each_ctx(hctx, ctx, i) - ctx->ipi_redirect = !!ret; - - return len; -} - static ssize_t blk_mq_hw_sysfs_tags_show(struct blk_mq_hw_ctx *hctx, char *page) { return blk_mq_tag_sysfs_show(hctx->tags, page); @@ -307,11 +271,6 @@ static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_pending = { .attr = {.name = "pending", .mode = S_IRUGO }, .show = blk_mq_hw_sysfs_rq_list_show, }; -static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_ipi = { - .attr = {.name = "ipi_redirect", .mode = S_IRUGO | S_IWUSR}, - .show = blk_mq_hw_sysfs_ipi_show, - .store = blk_mq_hw_sysfs_ipi_store, -}; static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_tags = { .attr = {.name = "tags", .mode = S_IRUGO }, .show = blk_mq_hw_sysfs_tags_show, @@ -326,7 +285,6 @@ static struct attribute *default_hw_ctx_attrs[] = { &blk_mq_hw_sysfs_run.attr, &blk_mq_hw_sysfs_dispatched.attr, &blk_mq_hw_sysfs_pending.attr, - &blk_mq_hw_sysfs_ipi.attr, &blk_mq_hw_sysfs_tags.attr, &blk_mq_hw_sysfs_cpus.attr, NULL, diff --git a/block/blk-mq.c b/block/blk-mq.c index a84112c94e74..f2e92eb92803 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -326,15 +326,19 @@ static void __blk_mq_complete_request_remote(void *data) void __blk_mq_complete_request(struct request *rq) { struct blk_mq_ctx *ctx = rq->mq_ctx; + bool shared = false; int cpu; - if (!ctx->ipi_redirect) { + if (!test_bit(QUEUE_FLAG_SAME_COMP, &rq->q->queue_flags)) { rq->q->softirq_done_fn(rq); return; } cpu = get_cpu(); - if (cpu != ctx->cpu && cpu_online(ctx->cpu)) { + if (!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags)) + shared = cpus_share_cache(cpu, ctx->cpu); + + if (cpu != ctx->cpu && !shared && cpu_online(ctx->cpu)) { rq->csd.func = __blk_mq_complete_request_remote; rq->csd.info = rq; rq->csd.flags = 0; diff --git a/block/blk-mq.h b/block/blk-mq.h index b41a784de50d..1ae364ceaf8b 100644 --- a/block/blk-mq.h +++ b/block/blk-mq.h @@ -11,7 +11,6 @@ struct blk_mq_ctx { unsigned int cpu; unsigned int index_hw; - unsigned int ipi_redirect; /* incremented at dispatch time */ unsigned long rq_dispatched[2]; diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index ab469d525894..3b561d651a02 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -122,7 +122,6 @@ enum { BLK_MQ_F_SHOULD_MERGE = 1 << 0, BLK_MQ_F_SHOULD_SORT = 1 << 1, - BLK_MQ_F_SHOULD_IPI = 1 << 2, BLK_MQ_S_STOPPED = 0, -- 2.30.2