From 4d92a9beb39d80a7d8ff7c04ae12a10290105ae5 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 29 May 2014 08:09:00 -0600 Subject: block: remove 'magic' from struct blk_plug I don't think we've ever caught any bugs with this, and there's the list poisoning for the plug lists to catch uninitialized cases. So remove the magic member and save 8 bytes in the struct. Signed-off-by: Jens Axboe --- include/linux/blkdev.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 913f1c2d3be0..098304576d51 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1060,7 +1060,6 @@ static inline void blk_post_runtime_resume(struct request_queue *q, int err) {} * schedule() where blk_schedule_flush_plug() is called. */ struct blk_plug { - unsigned long magic; /* detect uninitialized use-cases */ struct list_head list; /* requests */ struct list_head mq_list; /* blk-mq requests */ struct list_head cb_list; /* md requires an unplug callback */ -- cgit v1.2.3 From 05f1dd5315217398fc8d122bdee80f96a9f21274 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 29 May 2014 09:53:32 -0600 Subject: block: add queue flag for disabling SG merging If devices are not SG starved, we waste a lot of time potentially collapsing SG segments. Enough that 1.5% of the CPU time goes to this, at only 400K IOPS. Add a queue flag, QUEUE_FLAG_NO_SG_MERGE, which just returns the number of vectors in a bio instead of looping over all segments and checking for collapsible ones. Add a BLK_MQ_F_SG_MERGE flag so that drivers can opt-in on the sg merging, if they so desire. Signed-off-by: Jens Axboe --- include/linux/blk-mq.h | 1 + include/linux/blkdev.h | 1 + 2 files changed, 2 insertions(+) (limited to 'include/linux') diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index 91dfb75ce39f..95de239444d2 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -129,6 +129,7 @@ enum { BLK_MQ_F_SHOULD_MERGE = 1 << 0, BLK_MQ_F_SHOULD_SORT = 1 << 1, BLK_MQ_F_TAG_SHARED = 1 << 2, + BLK_MQ_F_SG_MERGE = 1 << 3, BLK_MQ_S_STOPPED = 0, BLK_MQ_S_TAG_ACTIVE = 1, diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 098304576d51..695b9fd41efe 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -510,6 +510,7 @@ struct request_queue { #define QUEUE_FLAG_SAME_FORCE 18 /* force complete on same CPU */ #define QUEUE_FLAG_DEAD 19 /* queue tear-down finished */ #define QUEUE_FLAG_INIT_DONE 20 /* queue is initialized */ +#define QUEUE_FLAG_NO_SG_MERGE 21 /* don't attempt to merge SG segments*/ #define QUEUE_FLAG_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \ (1 << QUEUE_FLAG_STACKABLE) | \ -- cgit v1.2.3 From 2230237500821aedfcf2bba2a79d9cbca389233c Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Fri, 30 May 2014 08:06:42 -0600 Subject: blk-mq: blk_mq_tag_to_rq should handle flush request flush request is special, which borrows the tag from the parent request. Hence blk_mq_tag_to_rq needs special handling to return the flush request from the tag. Signed-off-by: Shaohua Li Signed-off-by: Jens Axboe --- include/linux/blk-mq.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index 95de239444d2..ad3adb73cc70 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -154,7 +154,7 @@ void blk_mq_free_request(struct request *rq); bool blk_mq_can_queue(struct blk_mq_hw_ctx *); struct request *blk_mq_alloc_request(struct request_queue *q, int rw, gfp_t gfp, bool reserved); -struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag); +struct request *blk_mq_tag_to_rq(struct blk_mq_hw_ctx *hctx, unsigned int tag); struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *, const int ctx_index); struct blk_mq_hw_ctx *blk_mq_alloc_single_hw_queue(struct blk_mq_tag_set *, unsigned int, int); -- cgit v1.2.3