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authorPaolo Valente <paolo.valente@linaro.org>2021-01-25 20:02:48 +0100
committerJens Axboe <axboe@kernel.dk>2021-01-25 14:18:37 -0700
commit71217df39dc67a0aeed83352b0d712b7892036a2 (patch)
tree665b6a543e3f5818649e406badf6a4f57cd84d97 /block/bfq-iosched.h
parent5a5436b98d5cd2714feaaa579cec49dd7f7057bb (diff)
block, bfq: make waker-queue detection more robust
In the presence of many parallel I/O flows, the detection of waker bfq_queues suffers from false positives. This commits addresses this issue by making the filtering of actual wakers more selective. In more detail, a candidate waker must be found to meet waker requirements three times before being promoted to actual waker. Tested-by: Jan Kara <jack@suse.cz> Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/bfq-iosched.h')
-rw-r--r--block/bfq-iosched.h7
1 files changed, 5 insertions, 2 deletions
diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h
index 3f350fa3c5fd..b8e793c34ff1 100644
--- a/block/bfq-iosched.h
+++ b/block/bfq-iosched.h
@@ -376,6 +376,11 @@ struct bfq_queue {
* bfq_select_queue().
*/
struct bfq_queue *waker_bfqq;
+ /* pointer to the curr. tentative waker queue, see bfq_check_waker() */
+ struct bfq_queue *tentative_waker_bfqq;
+ /* number of times the same tentative waker has been detected */
+ unsigned int num_waker_detections;
+
/* node for woken_list, see below */
struct hlist_node woken_list_node;
/*
@@ -776,7 +781,6 @@ enum bfqq_state_flags {
*/
BFQQF_coop, /* bfqq is shared */
BFQQF_split_coop, /* shared bfqq will be split */
- BFQQF_has_waker /* bfqq has a waker queue */
};
#define BFQ_BFQQ_FNS(name) \
@@ -796,7 +800,6 @@ BFQ_BFQQ_FNS(in_large_burst);
BFQ_BFQQ_FNS(coop);
BFQ_BFQQ_FNS(split_coop);
BFQ_BFQQ_FNS(softrt_update);
-BFQ_BFQQ_FNS(has_waker);
#undef BFQ_BFQQ_FNS
/* Expiration reasons. */