| Message ID | 20210519121317.585244-5-david@fromorbit.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | xfs: CIL and log optimisations | expand |
On Wed, May 19, 2021 at 10:12:42PM +1000, Dave Chinner wrote: > From: Dave Chinner <dchinner@redhat.com> > > The new checkpoint cache flush mechanism requires us to issue an > unconditional cache flush before we start a new checkpoint. We don't > want to block for this if we can help it, and we have a fair chunk > of CPU work to do between starting the checkpoint and issuing the > first journal IO. > > Hence it makes sense to amortise the latency cost of the cache flush > by issuing it asynchronously and then waiting for it only when we > need to issue the first IO in the transaction. > > To do this, we need async cache flush primitives to submit the cache > flush bio and to wait on it. The block layer has no such primitives > for filesystems, so roll our own for the moment. > > Signed-off-by: Dave Chinner <dchinner@redhat.com> > Reviewed-by: Brian Foster <bfoster@redhat.com> Looks good to me, Reviewed-by: Darrick J. Wong <djwong@kernel.org> --D > --- > fs/xfs/xfs_bio_io.c | 35 +++++++++++++++++++++++++++++++++++ > fs/xfs/xfs_linux.h | 2 ++ > 2 files changed, 37 insertions(+) > > diff --git a/fs/xfs/xfs_bio_io.c b/fs/xfs/xfs_bio_io.c > index 17f36db2f792..de727532e137 100644 > --- a/fs/xfs/xfs_bio_io.c > +++ b/fs/xfs/xfs_bio_io.c > @@ -9,6 +9,41 @@ static inline unsigned int bio_max_vecs(unsigned int count) > return bio_max_segs(howmany(count, PAGE_SIZE)); > } > > +static void > +xfs_flush_bdev_async_endio( > + struct bio *bio) > +{ > + complete(bio->bi_private); > +} > + > +/* > + * Submit a request for an async cache flush to run. If the request queue does > + * not require flush operations, just skip it altogether. If the caller needsi > + * to wait for the flush completion at a later point in time, they must supply a > + * valid completion. This will be signalled when the flush completes. The > + * caller never sees the bio that is issued here. > + */ > +void > +xfs_flush_bdev_async( > + struct bio *bio, > + struct block_device *bdev, > + struct completion *done) > +{ > + struct request_queue *q = bdev->bd_disk->queue; > + > + if (!test_bit(QUEUE_FLAG_WC, &q->queue_flags)) { > + complete(done); > + return; > + } > + > + bio_init(bio, NULL, 0); > + bio_set_dev(bio, bdev); > + bio->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC; > + bio->bi_private = done; > + bio->bi_end_io = xfs_flush_bdev_async_endio; > + > + submit_bio(bio); > +} > int > xfs_rw_bdev( > struct block_device *bdev, > diff --git a/fs/xfs/xfs_linux.h b/fs/xfs/xfs_linux.h > index 7688663b9773..c174262a074e 100644 > --- a/fs/xfs/xfs_linux.h > +++ b/fs/xfs/xfs_linux.h > @@ -196,6 +196,8 @@ static inline uint64_t howmany_64(uint64_t x, uint32_t y) > > int xfs_rw_bdev(struct block_device *bdev, sector_t sector, unsigned int count, > char *data, unsigned int op); > +void xfs_flush_bdev_async(struct bio *bio, struct block_device *bdev, > + struct completion *done); > > #define ASSERT_ALWAYS(expr) \ > (likely(expr) ? (void)0 : assfail(NULL, #expr, __FILE__, __LINE__)) > -- > 2.31.1 >
On 5/19/21 5:12 AM, Dave Chinner wrote: > From: Dave Chinner <dchinner@redhat.com> > > The new checkpoint cache flush mechanism requires us to issue an > unconditional cache flush before we start a new checkpoint. We don't > want to block for this if we can help it, and we have a fair chunk > of CPU work to do between starting the checkpoint and issuing the > first journal IO. > > Hence it makes sense to amortise the latency cost of the cache flush > by issuing it asynchronously and then waiting for it only when we > need to issue the first IO in the transaction. > > To do this, we need async cache flush primitives to submit the cache > flush bio and to wait on it. The block layer has no such primitives > for filesystems, so roll our own for the moment. > > Signed-off-by: Dave Chinner <dchinner@redhat.com> > Reviewed-by: Brian Foster <bfoster@redhat.com> > --- > fs/xfs/xfs_bio_io.c | 35 +++++++++++++++++++++++++++++++++++ > fs/xfs/xfs_linux.h | 2 ++ > 2 files changed, 37 insertions(+) > > diff --git a/fs/xfs/xfs_bio_io.c b/fs/xfs/xfs_bio_io.c > index 17f36db2f792..de727532e137 100644 > --- a/fs/xfs/xfs_bio_io.c > +++ b/fs/xfs/xfs_bio_io.c > @@ -9,6 +9,41 @@ static inline unsigned int bio_max_vecs(unsigned int count) > return bio_max_segs(howmany(count, PAGE_SIZE)); > } > > +static void > +xfs_flush_bdev_async_endio( > + struct bio *bio) > +{ > + complete(bio->bi_private); > +} > + > +/* > + * Submit a request for an async cache flush to run. If the request queue does > + * not require flush operations, just skip it altogether. If the caller needsi typo nit: needs Otherwise looks fine Reviewed-by: Allison Henderson <allison.henderson@oracle.com> > + * to wait for the flush completion at a later point in time, they must supply a > + * valid completion. This will be signalled when the flush completes. The > + * caller never sees the bio that is issued here. > + */ > +void > +xfs_flush_bdev_async( > + struct bio *bio, > + struct block_device *bdev, > + struct completion *done) > +{ > + struct request_queue *q = bdev->bd_disk->queue; > + > + if (!test_bit(QUEUE_FLAG_WC, &q->queue_flags)) { > + complete(done); > + return; > + } > + > + bio_init(bio, NULL, 0); > + bio_set_dev(bio, bdev); > + bio->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC; > + bio->bi_private = done; > + bio->bi_end_io = xfs_flush_bdev_async_endio; > + > + submit_bio(bio); > +} > int > xfs_rw_bdev( > struct block_device *bdev, > diff --git a/fs/xfs/xfs_linux.h b/fs/xfs/xfs_linux.h > index 7688663b9773..c174262a074e 100644 > --- a/fs/xfs/xfs_linux.h > +++ b/fs/xfs/xfs_linux.h > @@ -196,6 +196,8 @@ static inline uint64_t howmany_64(uint64_t x, uint32_t y) > > int xfs_rw_bdev(struct block_device *bdev, sector_t sector, unsigned int count, > char *data, unsigned int op); > +void xfs_flush_bdev_async(struct bio *bio, struct block_device *bdev, > + struct completion *done); > > #define ASSERT_ALWAYS(expr) \ > (likely(expr) ? (void)0 : assfail(NULL, #expr, __FILE__, __LINE__)) >
diff --git a/fs/xfs/xfs_bio_io.c b/fs/xfs/xfs_bio_io.c index 17f36db2f792..de727532e137 100644 --- a/fs/xfs/xfs_bio_io.c +++ b/fs/xfs/xfs_bio_io.c @@ -9,6 +9,41 @@ static inline unsigned int bio_max_vecs(unsigned int count) return bio_max_segs(howmany(count, PAGE_SIZE)); } +static void +xfs_flush_bdev_async_endio( + struct bio *bio) +{ + complete(bio->bi_private); +} + +/* + * Submit a request for an async cache flush to run. If the request queue does + * not require flush operations, just skip it altogether. If the caller needsi + * to wait for the flush completion at a later point in time, they must supply a + * valid completion. This will be signalled when the flush completes. The + * caller never sees the bio that is issued here. + */ +void +xfs_flush_bdev_async( + struct bio *bio, + struct block_device *bdev, + struct completion *done) +{ + struct request_queue *q = bdev->bd_disk->queue; + + if (!test_bit(QUEUE_FLAG_WC, &q->queue_flags)) { + complete(done); + return; + } + + bio_init(bio, NULL, 0); + bio_set_dev(bio, bdev); + bio->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC; + bio->bi_private = done; + bio->bi_end_io = xfs_flush_bdev_async_endio; + + submit_bio(bio); +} int xfs_rw_bdev( struct block_device *bdev, diff --git a/fs/xfs/xfs_linux.h b/fs/xfs/xfs_linux.h index 7688663b9773..c174262a074e 100644 --- a/fs/xfs/xfs_linux.h +++ b/fs/xfs/xfs_linux.h @@ -196,6 +196,8 @@ static inline uint64_t howmany_64(uint64_t x, uint32_t y) int xfs_rw_bdev(struct block_device *bdev, sector_t sector, unsigned int count, char *data, unsigned int op); +void xfs_flush_bdev_async(struct bio *bio, struct block_device *bdev, + struct completion *done); #define ASSERT_ALWAYS(expr) \ (likely(expr) ? (void)0 : assfail(NULL, #expr, __FILE__, __LINE__))