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block: get rid of plug list sorting

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Even if we have multiple queues in the plug list, chances that they
are very interspersed is minimal. Don't bother spending CPU cycles
sorting the list.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2021-10-18 10:08:49 -06:00
parent 87c037d11b
commit df87eb0fce
1 changed files with 0 additions and 19 deletions
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19
block/blk-mq.c
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@ -19,7 +19,6 @@
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/llist.h>
#include <linux/list_sort.h>
#include <linux/cpu.h>
#include <linux/cache.h>
#include <linux/sched/sysctl.h>
@ -2161,20 +2160,6 @@ void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx,
spin_unlock(&ctx->lock);
}
static int plug_rq_cmp(void *priv, const struct list_head *a,
const struct list_head *b)
{
struct request *rqa = container_of(a, struct request, queuelist);
struct request *rqb = container_of(b, struct request, queuelist);
if (rqa->mq_ctx != rqb->mq_ctx)
return rqa->mq_ctx > rqb->mq_ctx;
if (rqa->mq_hctx != rqb->mq_hctx)
return rqa->mq_hctx > rqb->mq_hctx;
return blk_rq_pos(rqa) > blk_rq_pos(rqb);
}
void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
{
LIST_HEAD(list);
@ -2182,10 +2167,6 @@ void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
if (list_empty(&plug->mq_list))
return;
list_splice_init(&plug->mq_list, &list);
if (plug->rq_count > 2 && plug->multiple_queues)
list_sort(NULL, &list, plug_rq_cmp);
plug->rq_count = 0;
do {