Messages in this thread | | | Date | Thu, 27 Oct 2022 10:09:35 +0100 | Subject | Re: [PATCH RFC v3 01/22] blk-mq: Don't get budget for reserved requests | From | John Garry <> |
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On 27/10/2022 02:16, Damien Le Moal wrote: >> Signed-off-by: John Garry<john.garry@huawei.com> >> --- >> block/blk-mq.c | 4 +++- >> drivers/scsi/scsi_lib.c | 3 ++- >> 2 files changed, 5 insertions(+), 2 deletions(-) >> >> diff --git a/block/blk-mq.c b/block/blk-mq.c >> index 260adeb2e455..d8baabb32ea4 100644 >> --- a/block/blk-mq.c >> +++ b/block/blk-mq.c >> @@ -1955,11 +1955,13 @@ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list, >> errors = queued = 0; >> do { >> struct blk_mq_queue_data bd; >> + bool need_budget; >> >> rq = list_first_entry(list, struct request, queuelist); >> >> WARN_ON_ONCE(hctx != rq->mq_hctx); >> - prep = blk_mq_prep_dispatch_rq(rq, !nr_budgets); >> + need_budget = !nr_budgets && !blk_mq_is_reserved_rq(rq); >> + prep = blk_mq_prep_dispatch_rq(rq, need_budget); >> if (prep != PREP_DISPATCH_OK) >> break; > Below this code, there is: > > if (nr_budgets) > nr_budgets--; > > Don't you need to change that to: > > if (need_budget && nr_budgets) > nr_budgets--; > > ? Otherwise, the accounting will be off. >
Ah, yes, I think that you are right. I actually need to check nr_budgets usage further as nr_budgets initial value would be dependent on any reserved request requiring a budget (which we don't get).
Thanks, John
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