block: remove PSI accounting from the bio layer

PSI accounting is now done by the VM code, where it should have been
since the beginning.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Link: https://lore.kernel.org/r/20220915094200.139713-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/bio.c

@@ -1063,9 +1063,6 @@ void __bio_add_page(struct bio *bio, struct page *page,
 
 	bio->bi_iter.bi_size += len;
 	bio->bi_vcnt++;
-
-	if (!bio_flagged(bio, BIO_WORKINGSET) && unlikely(PageWorkingset(page)))
-		bio_set_flag(bio, BIO_WORKINGSET);
 }
 EXPORT_SYMBOL_GPL(__bio_add_page);
 
@@ -1274,9 +1271,6 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
  * fit into the bio, or are requested in @iter, whatever is smaller. If
  * MM encounters an error pinning the requested pages, it stops. Error
  * is returned only if 0 pages could be pinned.
- *
- * It's intended for direct IO, so doesn't do PSI tracking, the caller is
- * responsible for setting BIO_WORKINGSET if necessary.
  */
 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
 {
@@ -1292,8 +1286,6 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
 		ret = __bio_iov_iter_get_pages(bio, iter);
 	} while (!ret && iov_iter_count(iter) && !bio_full(bio, 0));
 
-	/* don't account direct I/O as memory stall */
-	bio_clear_flag(bio, BIO_WORKINGSET);
 	return bio->bi_vcnt ? 0 : ret;
 }
 EXPORT_SYMBOL_GPL(bio_iov_iter_get_pages);

block/blk-core.c

@@ -37,7 +37,6 @@
 #include <linux/t10-pi.h>
 #include <linux/debugfs.h>
 #include <linux/bpf.h>
-#include <linux/psi.h>
 #include <linux/part_stat.h>
 #include <linux/sched/sysctl.h>
 #include <linux/blk-crypto.h>
@@ -825,22 +824,6 @@ void submit_bio(struct bio *bio)
 		count_vm_events(PGPGOUT, bio_sectors(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 (unlikely(bio_op(bio) == REQ_OP_READ &&
-	    bio_flagged(bio, BIO_WORKINGSET))) {
-		unsigned long pflags;
-
-		psi_memstall_enter(&pflags);
-		submit_bio_noacct(bio);
-		psi_memstall_leave(&pflags);
-		return;
-	}
-
 	submit_bio_noacct(bio);
 }
 EXPORT_SYMBOL(submit_bio);

fs/direct-io.c

@@ -421,8 +421,6 @@ static inline void dio_bio_submit(struct dio *dio, struct dio_submit *sdio)
 	unsigned long flags;
 
 	bio->bi_private = dio;
-	/* don't account direct I/O as memory stall */
-	bio_clear_flag(bio, BIO_WORKINGSET);
 
 	spin_lock_irqsave(&dio->bio_lock, flags);
 	dio->refcount++;

include/linux/blk_types.h

@@ -321,7 +321,6 @@ enum {
 	BIO_NO_PAGE_REF,	/* don't put release vec pages */
 	BIO_CLONED,		/* doesn't own data */
 	BIO_BOUNCED,		/* bio is a bounce bio */
-	BIO_WORKINGSET,		/* contains userspace workingset pages */
 	BIO_QUIET,		/* Make BIO Quiet */
 	BIO_CHAIN,		/* chained bio, ->bi_remaining in effect */
 	BIO_REFFED,		/* bio has elevated ->bi_cnt */