| Message ID | 1543995842-20704-2-git-send-email-jianchao.w.wang@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | blk-mq: refactor code of issue directly | expand |
On 12/5/18 12:43 AM, Jianchao Wang wrote: > We don't allow direct dispatch of anything but regular reads/writes > and insert all of non-read-write requests. However, this is not > correct for 'bypass_insert == true' case where inserting is ignored > and BLK_STS_RESOURCE is returned. The caller will fail forever. > > Fix it with inserting the non-read-write request to hctx dispatch > list to avoid to involve merge and io scheduler when bypass_insert > is true. > > Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> > --- > block/blk-mq.c | 19 +++++++++++++++++-- > 1 file changed, 17 insertions(+), 2 deletions(-) > > diff --git a/block/blk-mq.c b/block/blk-mq.c > index 9005505..153af90 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -1822,6 +1822,7 @@ static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, > { > struct request_queue *q = rq->q; > bool run_queue = true; > + bool force = false; > > /* > * RCU or SRCU read lock is needed before checking quiesced flag. > @@ -1836,9 +1837,19 @@ static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, > goto insert; > } > > - if (!blk_rq_can_direct_dispatch(rq) || (q->elevator && !bypass_insert)) > + if (q->elevator && !bypass_insert) > goto insert; > > + if (!blk_rq_can_direct_dispatch(rq)) { > + /* > + * For 'bypass_insert == true' case, insert request into hctx > + * dispatch list. > + */ > + if (bypass_insert) > + force = true; > + goto insert; > + } Just do force = bypass_insert, no need for the if.
On 12/6/18 12:25 AM, Jens Axboe wrote: > On 12/5/18 12:43 AM, Jianchao Wang wrote: >> We don't allow direct dispatch of anything but regular reads/writes >> and insert all of non-read-write requests. However, this is not >> correct for 'bypass_insert == true' case where inserting is ignored >> and BLK_STS_RESOURCE is returned. The caller will fail forever. >> >> Fix it with inserting the non-read-write request to hctx dispatch >> list to avoid to involve merge and io scheduler when bypass_insert >> is true. >> >> Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> >> --- >> block/blk-mq.c | 19 +++++++++++++++++-- >> 1 file changed, 17 insertions(+), 2 deletions(-) >> >> diff --git a/block/blk-mq.c b/block/blk-mq.c >> index 9005505..153af90 100644 >> --- a/block/blk-mq.c >> +++ b/block/blk-mq.c >> @@ -1822,6 +1822,7 @@ static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, >> { >> struct request_queue *q = rq->q; >> bool run_queue = true; >> + bool force = false; >> >> /* >> * RCU or SRCU read lock is needed before checking quiesced flag. >> @@ -1836,9 +1837,19 @@ static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, >> goto insert; >> } >> >> - if (!blk_rq_can_direct_dispatch(rq) || (q->elevator && !bypass_insert)) >> + if (q->elevator && !bypass_insert) >> goto insert; >> >> + if (!blk_rq_can_direct_dispatch(rq)) { >> + /* >> + * For 'bypass_insert == true' case, insert request into hctx >> + * dispatch list. >> + */ >> + if (bypass_insert) >> + force = true; >> + goto insert; >> + } > > Just do force = bypass_insert, no need for the if. > Yes, I will do it. Thanks Jianchao
diff --git a/block/blk-mq.c b/block/blk-mq.c index 9005505..153af90 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1822,6 +1822,7 @@ static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, { struct request_queue *q = rq->q; bool run_queue = true; + bool force = false; /* * RCU or SRCU read lock is needed before checking quiesced flag. @@ -1836,9 +1837,19 @@ static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, goto insert; } - if (!blk_rq_can_direct_dispatch(rq) || (q->elevator && !bypass_insert)) + if (q->elevator && !bypass_insert) goto insert; + if (!blk_rq_can_direct_dispatch(rq)) { + /* + * For 'bypass_insert == true' case, insert request into hctx + * dispatch list. + */ + if (bypass_insert) + force = true; + goto insert; + } + if (!blk_mq_get_dispatch_budget(hctx)) goto insert; @@ -1849,8 +1860,12 @@ static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, return __blk_mq_issue_directly(hctx, rq, cookie, last); insert: - if (bypass_insert) + if (force) { + blk_mq_request_bypass_insert(rq, run_queue); + return BLK_STS_OK; + } else if (bypass_insert) { return BLK_STS_RESOURCE; + } blk_mq_sched_insert_request(rq, false, run_queue, false); return BLK_STS_OK;
We don't allow direct dispatch of anything but regular reads/writes and insert all of non-read-write requests. However, this is not correct for 'bypass_insert == true' case where inserting is ignored and BLK_STS_RESOURCE is returned. The caller will fail forever. Fix it with inserting the non-read-write request to hctx dispatch list to avoid to involve merge and io scheduler when bypass_insert is true. Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> --- block/blk-mq.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-)