From 0cf41e5e9bafc185490624c3e321c915885a91f3 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Sat, 9 Jan 2021 16:02:59 +0000 Subject: [PATCH] block/psi: remove PSI annotations from direct IO Direct IO does not operate on the current working set of pages managed by the kernel, so it should not be accounted as memory stall to PSI infrastructure. The block layer and iomap direct IO use bio_iov_iter_get_pages() to build bios, and they are the only users of it, so to avoid PSI tracking for them clear out BIO_WORKINGSET flag. Do same for dio_bio_submit() because fs/direct_io constructs bios by hand directly calling bio_add_page(). Reported-by: Christoph Hellwig Suggested-by: Christoph Hellwig Suggested-by: Johannes Weiner Reviewed-by: Christoph Hellwig Signed-off-by: Pavel Begunkov Reviewed-by: Ming Lei Signed-off-by: Jens Axboe --- block/bio.c | 6 ++++++ fs/direct-io.c | 2 ++ 2 files changed, 8 insertions(+) diff --git a/block/bio.c b/block/bio.c index 56a06f9..1cd8a2e 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1081,6 +1081,9 @@ static int __bio_iov_append_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) { @@ -1105,6 +1108,9 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) if (is_bvec) bio_set_flag(bio, BIO_NO_PAGE_REF); + + /* 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); diff --git a/fs/direct-io.c b/fs/direct-io.c index 2660e74..aa1083ec 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -426,6 +426,8 @@ 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++; -- 2.7.4