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authorJens Axboe <axboe@kernel.dk>2018-05-07 10:03:23 -0600
committerJens Axboe <axboe@kernel.dk>2018-05-08 15:11:02 -0600
commit782f569774d7000e54ae9d680b0e4cd29b1c7ca3 (patch)
tree137bb8ebd2903af1d82fb9159ccc5a06b9005335 /block/blk-wbt.c
parent8bea60901974ad44b06b08d52e1dd421ea8c6e9c (diff)
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blk-wbt: throttle discards like background writes
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. Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-wbt.c')
-rw-r--r--block/blk-wbt.c43
1 files changed, 26 insertions, 17 deletions
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);