| Message ID | 1525709615-14395-5-git-send-email-axboe@kernel.dk (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
On Mon, May 07, 2018 at 10:13:35AM -0600, Jens Axboe wrote: > Throttle discards like we would any background write. Discards should > be background activity, so if they are impacting foreground IO, then > we will throttle them down. > > Signed-off-by: Jens Axboe <axboe@kernel.dk> Looks ok, Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> --D > --- > block/blk-stat.h | 6 +++--- > block/blk-wbt.c | 43 ++++++++++++++++++++++++++----------------- > block/blk-wbt.h | 4 +++- > 3 files changed, 32 insertions(+), 21 deletions(-) > > diff --git a/block/blk-stat.h b/block/blk-stat.h > index 2dd36347252a..c22049a8125e 100644 > --- a/block/blk-stat.h > +++ b/block/blk-stat.h > @@ -10,11 +10,11 @@ > > /* > * from upper: > - * 3 bits: reserved for other usage > + * 4 bits: reserved for other usage > * 12 bits: size > - * 49 bits: time > + * 48 bits: time > */ > -#define BLK_STAT_RES_BITS 3 > +#define BLK_STAT_RES_BITS 4 > #define BLK_STAT_SIZE_BITS 12 > #define BLK_STAT_RES_SHIFT (64 - BLK_STAT_RES_BITS) > #define BLK_STAT_SIZE_SHIFT (BLK_STAT_RES_SHIFT - BLK_STAT_SIZE_BITS) > diff --git a/block/blk-wbt.c b/block/blk-wbt.c > index 25d202345965..a7a724580033 100644 > --- a/block/blk-wbt.c > +++ b/block/blk-wbt.c > @@ -106,6 +106,8 @@ static inline struct rq_wait *get_rq_wait(struct rq_wb *rwb, > { > if (wb_acct & WBT_KSWAPD) > return &rwb->rq_wait[WBT_RWQ_KSWAPD]; > + else if (wb_acct & WBT_DISCARD) > + return &rwb->rq_wait[WBT_RWQ_DISCARD]; > > return &rwb->rq_wait[WBT_RWQ_BG]; > } > @@ -143,10 +145,13 @@ void __wbt_done(struct rq_wb *rwb, enum wbt_flags wb_acct) > } > > /* > - * If the device does write back caching, drop further down > - * before we wake people up. > + * For discards, our limit is always the background. For writes, if > + * the device does write back caching, drop further down before we > + * wake people up. > */ > - if (rwb->wc && !wb_recent_wait(rwb)) > + if (wb_acct & WBT_DISCARD) > + limit = rwb->wb_background; > + else if (rwb->wc && !wb_recent_wait(rwb)) > limit = 0; > else > limit = rwb->wb_normal; > @@ -483,6 +488,9 @@ static inline unsigned int get_limit(struct rq_wb *rwb, unsigned long rw) > { > unsigned int limit; > > + if ((rw & REQ_OP_MASK) == REQ_OP_DISCARD) > + return rwb->wb_background; > + > /* > * At this point we know it's a buffered write. If this is > * kswapd trying to free memory, or REQ_SYNC is set, then > @@ -564,21 +572,20 @@ static void __wbt_wait(struct rq_wb *rwb, enum wbt_flags wb_acct, > > static inline bool wbt_should_throttle(struct rq_wb *rwb, struct bio *bio) > { > - const int op = bio_op(bio); > - > - /* > - * If not a WRITE, do nothing > - */ > - if (op != REQ_OP_WRITE) > - return false; > - > - /* > - * Don't throttle WRITE_ODIRECT > - */ > - if ((bio->bi_opf & (REQ_SYNC | REQ_IDLE)) == (REQ_SYNC | REQ_IDLE)) > + switch (bio_op(bio)) { > + case REQ_OP_WRITE: > + /* > + * Don't throttle WRITE_ODIRECT > + */ > + if ((bio->bi_opf & (REQ_SYNC | REQ_IDLE)) == > + (REQ_SYNC | REQ_IDLE)) > + return false; > + /* fallthrough */ > + case REQ_OP_DISCARD: > + return true; > + default: > return false; > - > - return true; > + } > } > > /* > @@ -605,6 +612,8 @@ enum wbt_flags wbt_wait(struct rq_wb *rwb, struct bio *bio, spinlock_t *lock) > > if (current_is_kswapd()) > ret |= WBT_KSWAPD; > + if (bio_op(bio) == REQ_OP_DISCARD) > + ret |= WBT_DISCARD; > > __wbt_wait(rwb, ret, bio->bi_opf, lock); > > diff --git a/block/blk-wbt.h b/block/blk-wbt.h > index 8038b4a0d4ef..d6a125e49db5 100644 > --- a/block/blk-wbt.h > +++ b/block/blk-wbt.h > @@ -14,13 +14,15 @@ enum wbt_flags { > WBT_TRACKED = 1, /* write, tracked for throttling */ > WBT_READ = 2, /* read */ > WBT_KSWAPD = 4, /* write, from kswapd */ > + WBT_DISCARD = 8, /* discard */ > > - WBT_NR_BITS = 3, /* number of bits */ > + WBT_NR_BITS = 4, /* number of bits */ > }; > > enum { > WBT_RWQ_BG = 0, > WBT_RWQ_KSWAPD, > + WBT_RWQ_DISCARD, > WBT_NUM_RWQ, > }; > > -- > 2.7.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, May 07, 2018 at 10:13:35AM -0600, Jens Axboe wrote: > Throttle discards like we would any background write. Discards should > be background activity, so if they are impacting foreground IO, then > we will throttle them down. Seems reasonable. Reviewed-by: Omar Sandoval <osandov@fb.com> > Signed-off-by: Jens Axboe <axboe@kernel.dk> > --- > block/blk-stat.h | 6 +++--- > block/blk-wbt.c | 43 ++++++++++++++++++++++++++----------------- > block/blk-wbt.h | 4 +++- > 3 files changed, 32 insertions(+), 21 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/block/blk-stat.h b/block/blk-stat.h index 2dd36347252a..c22049a8125e 100644 --- a/block/blk-stat.h +++ b/block/blk-stat.h @@ -10,11 +10,11 @@ /* * from upper: - * 3 bits: reserved for other usage + * 4 bits: reserved for other usage * 12 bits: size - * 49 bits: time + * 48 bits: time */ -#define BLK_STAT_RES_BITS 3 +#define BLK_STAT_RES_BITS 4 #define BLK_STAT_SIZE_BITS 12 #define BLK_STAT_RES_SHIFT (64 - BLK_STAT_RES_BITS) #define BLK_STAT_SIZE_SHIFT (BLK_STAT_RES_SHIFT - BLK_STAT_SIZE_BITS) diff --git a/block/blk-wbt.c b/block/blk-wbt.c index 25d202345965..a7a724580033 100644 --- a/block/blk-wbt.c +++ b/block/blk-wbt.c @@ -106,6 +106,8 @@ static inline struct rq_wait *get_rq_wait(struct rq_wb *rwb, { if (wb_acct & WBT_KSWAPD) return &rwb->rq_wait[WBT_RWQ_KSWAPD]; + else if (wb_acct & WBT_DISCARD) + return &rwb->rq_wait[WBT_RWQ_DISCARD]; return &rwb->rq_wait[WBT_RWQ_BG]; } @@ -143,10 +145,13 @@ void __wbt_done(struct rq_wb *rwb, enum wbt_flags wb_acct) } /* - * If the device does write back caching, drop further down - * before we wake people up. + * For discards, our limit is always the background. For writes, if + * the device does write back caching, drop further down before we + * wake people up. */ - if (rwb->wc && !wb_recent_wait(rwb)) + if (wb_acct & WBT_DISCARD) + limit = rwb->wb_background; + else if (rwb->wc && !wb_recent_wait(rwb)) limit = 0; else limit = rwb->wb_normal; @@ -483,6 +488,9 @@ static inline unsigned int get_limit(struct rq_wb *rwb, unsigned long rw) { unsigned int limit; + if ((rw & REQ_OP_MASK) == REQ_OP_DISCARD) + return rwb->wb_background; + /* * At this point we know it's a buffered write. If this is * kswapd trying to free memory, or REQ_SYNC is set, then @@ -564,21 +572,20 @@ static void __wbt_wait(struct rq_wb *rwb, enum wbt_flags wb_acct, static inline bool wbt_should_throttle(struct rq_wb *rwb, struct bio *bio) { - const int op = bio_op(bio); - - /* - * If not a WRITE, do nothing - */ - if (op != REQ_OP_WRITE) - return false; - - /* - * Don't throttle WRITE_ODIRECT - */ - if ((bio->bi_opf & (REQ_SYNC | REQ_IDLE)) == (REQ_SYNC | REQ_IDLE)) + switch (bio_op(bio)) { + case REQ_OP_WRITE: + /* + * Don't throttle WRITE_ODIRECT + */ + if ((bio->bi_opf & (REQ_SYNC | REQ_IDLE)) == + (REQ_SYNC | REQ_IDLE)) + return false; + /* fallthrough */ + case REQ_OP_DISCARD: + return true; + default: return false; - - return true; + } } /* @@ -605,6 +612,8 @@ enum wbt_flags wbt_wait(struct rq_wb *rwb, struct bio *bio, spinlock_t *lock) if (current_is_kswapd()) ret |= WBT_KSWAPD; + if (bio_op(bio) == REQ_OP_DISCARD) + ret |= WBT_DISCARD; __wbt_wait(rwb, ret, bio->bi_opf, lock); diff --git a/block/blk-wbt.h b/block/blk-wbt.h index 8038b4a0d4ef..d6a125e49db5 100644 --- a/block/blk-wbt.h +++ b/block/blk-wbt.h @@ -14,13 +14,15 @@ enum wbt_flags { WBT_TRACKED = 1, /* write, tracked for throttling */ WBT_READ = 2, /* read */ WBT_KSWAPD = 4, /* write, from kswapd */ + WBT_DISCARD = 8, /* discard */ - WBT_NR_BITS = 3, /* number of bits */ + WBT_NR_BITS = 4, /* number of bits */ }; enum { WBT_RWQ_BG = 0, WBT_RWQ_KSWAPD, + WBT_RWQ_DISCARD, WBT_NUM_RWQ, };
Throttle discards like we would any background write. Discards should be background activity, so if they are impacting foreground IO, then we will throttle them down. Signed-off-by: Jens Axboe <axboe@kernel.dk> --- block/blk-stat.h | 6 +++--- block/blk-wbt.c | 43 ++++++++++++++++++++++++++----------------- block/blk-wbt.h | 4 +++- 3 files changed, 32 insertions(+), 21 deletions(-)