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 <[email protected]> --- block/blk-stat.h | 6 +++--- block/blk-wbt.c | 52 ++++++++++++++++++++++++++++++++++------------------ block/blk-wbt.h | 9 +++++++-- 3 files changed, 44 insertions(+), 23 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 3e34b41bcefc..4d222100746c 100644 --- a/block/blk-wbt.c +++ b/block/blk-wbt.c @@ -101,9 +101,15 @@ static bool wb_recent_wait(struct rq_wb *rwb) return time_before(jiffies, wb->dirty_sleep + HZ); } -static inline struct rq_wait *get_rq_wait(struct rq_wb *rwb, bool is_kswapd) +static inline struct rq_wait *get_rq_wait(struct rq_wb *rwb, bool is_trim, + bool is_kswapd) { - return &rwb->rq_wait[is_kswapd]; + if (is_trim) + return &rwb->rq_wait[WBT_REQ_DISCARD]; + else if (is_kswapd) + return &rwb->rq_wait[WBT_REQ_KSWAPD]; + else + return &rwb->rq_wait[WBT_REQ_BG]; } static void rwb_wake_all(struct rq_wb *rwb) @@ -120,13 +126,14 @@ static void rwb_wake_all(struct rq_wb *rwb) void __wbt_done(struct rq_wb *rwb, enum wbt_flags wb_acct) { + const bool is_trim = wb_acct & WBT_DISCARD; struct rq_wait *rqw; int inflight, limit; if (!(wb_acct & WBT_TRACKED)) return; - rqw = get_rq_wait(rwb, wb_acct & WBT_KSWAPD); + rqw = get_rq_wait(rwb, is_trim, wb_acct & WBT_KSWAPD); inflight = atomic_dec_return(&rqw->inflight); /* @@ -139,10 +146,13 @@ 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 (is_trim) + limit = rwb->wb_background; + else if (rwb->wc && !wb_recent_wait(rwb)) limit = 0; else limit = rwb->wb_normal; @@ -479,6 +489,9 @@ 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 @@ -533,7 +546,8 @@ static void __wbt_wait(struct rq_wb *rwb, unsigned long rw, spinlock_t *lock) __releases(lock) __acquires(lock) { - struct rq_wait *rqw = get_rq_wait(rwb, current_is_kswapd()); + const bool is_trim = (rw & REQ_OP_MASK) == REQ_OP_DISCARD; + struct rq_wait *rqw = get_rq_wait(rwb, is_trim, current_is_kswapd()); DEFINE_WAIT(wait); if (may_queue(rwb, rqw, &wait, rw)) @@ -561,19 +575,19 @@ 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; + if (op == REQ_OP_WRITE) { + /* + * Don't throttle WRITE_ODIRECT + */ + if ((bio->bi_opf & (REQ_SYNC | REQ_IDLE)) == + (REQ_SYNC | REQ_IDLE)) + return false; - /* - * Don't throttle WRITE_ODIRECT - */ - if ((bio->bi_opf & (REQ_SYNC | REQ_IDLE)) == (REQ_SYNC | REQ_IDLE)) - return false; + return true; + } else if (op == REQ_OP_DISCARD) + return true; - return true; + return false; } /* @@ -605,6 +619,8 @@ 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; return ret | WBT_TRACKED; } diff --git a/block/blk-wbt.h b/block/blk-wbt.h index a232c98fbf4d..af451876ea31 100644 --- a/block/blk-wbt.h +++ b/block/blk-wbt.h @@ -14,12 +14,17 @@ enum wbt_flags { WBT_TRACKED = 1, /* write, tracked for throttling */ WBT_READ = 2, /* read */ WBT_KSWAPD = 4, /* write, from kswapd */ + WBT_DISCARD = 8, - WBT_NR_BITS = 3, /* number of bits */ + WBT_NR_BITS = 4, /* number of bits */ }; enum { - WBT_NUM_RWQ = 2, + WBT_REQ_BG = 0, + WBT_REQ_KSWAPD, + WBT_REQ_DISCARD, + + WBT_NUM_RWQ, }; /* -- 2.7.4
