Commit 760f83ea authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block: cleanup the memory stall accounting in submit_bio 



Instead of a convoluted chain just check for REQ_OP_READ directly,
and keep all the memory stall code together in a single unlikely
branch.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 3fdd4086

block/blk-core.c

+14 −16
Original line number Diff line number Diff line
@@ -1148,10 +1148,6 @@ EXPORT_SYMBOL_GPL(direct_make_request); 
 */

blk_qc_t submit_bio(struct bio *bio)

{

	bool workingset_read = false;

	unsigned long pflags;

	blk_qc_t ret;



	if (blkcg_punt_bio_submit(bio))

		return BLK_QC_T_NONE;
@@ -1170,8 +1166,6 @@ blk_qc_t submit_bio(struct bio *bio) 
		if (op_is_write(bio_op(bio))) {

			count_vm_events(PGPGOUT, count);

		} else {

			if (bio_flagged(bio, BIO_WORKINGSET))

				workingset_read = true;

			task_io_account_read(bio->bi_iter.bi_size);

			count_vm_events(PGPGIN, count);

		}
@@ -1187,21 +1181,25 @@ blk_qc_t submit_bio(struct bio *bio) 
	}



	/*

	 * If we're reading data that is part of the userspace

	 * workingset, count submission time as memory stall. When the

	 * device is congested, or the submitting cgroup IO-throttled,

	 * submission can be a significant part of overall IO time.

	 * If we're reading data that is part of the userspace workingset, count

	 * submission time as memory stall.  When the device is congested, or

	 * the submitting cgroup IO-throttled, submission can be a significant

	 * part of overall IO time.

	 */

	if (workingset_read)

		psi_memstall_enter(&pflags);

	if (unlikely(bio_op(bio) == REQ_OP_READ &&

	    bio_flagged(bio, BIO_WORKINGSET))) {

		unsigned long pflags;

		blk_qc_t ret;



		psi_memstall_enter(&pflags);

		ret = generic_make_request(bio);



	if (workingset_read)

		psi_memstall_leave(&pflags);



		return ret;

	}



	return generic_make_request(bio);

}

EXPORT_SYMBOL(submit_bio);



/**

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