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| author | Pavel Begunkov <asml.silence@gmail.com> | 2020-04-15 00:39:50 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-04-15 04:16:59 +0300 |
| commit | 31af27c7cc9f675d93a135dca99e6413f9096f1d (patch) | |
| tree | fb117c1957897b8eff97aec74593fb86c810e69f /fs | |
| parent | b55ce732004989c85bf9d858c03e6d477cf9023b (diff) | |
| download | linux-31af27c7cc9f675d93a135dca99e6413f9096f1d.tar.xz | |
io_uring: don't count rqs failed after current one
When checking for draining with __req_need_defer(), it tries to match
how many requests were sent before a current one with number of already
completed. Dropped SQEs are included in req->sequence, and they won't
ever appear in CQ. To compensate for that, __req_need_defer() substracts
ctx->cached_sq_dropped.
However, what it should really use is number of SQEs dropped __before__
the current one. In other words, any submitted request shouldn't
shouldn't affect dequeueing from the drain queue of previously submitted
ones.
Instead of saving proper ctx->cached_sq_dropped in each request,
substract from req->sequence it at initialisation, so it includes number
of properly submitted requests.
note: it also changes behaviour of timeouts, but
1. it's already diverge from the description because of using SQ
2. the description is ambiguous regarding dropped SQEs
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/io_uring.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index 3fc33ba4855d..381d50becd04 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -957,8 +957,8 @@ static inline bool __req_need_defer(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; - return req->sequence != ctx->cached_cq_tail + ctx->cached_sq_dropped - + atomic_read(&ctx->cached_cq_overflow); + return req->sequence != ctx->cached_cq_tail + + atomic_read(&ctx->cached_cq_overflow); } static inline bool req_need_defer(struct io_kiocb *req) @@ -5801,7 +5801,7 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req, * it can be used to mark the position of the first IO in the * link list. */ - req->sequence = ctx->cached_sq_head; + req->sequence = ctx->cached_sq_head - ctx->cached_sq_dropped; req->opcode = READ_ONCE(sqe->opcode); req->user_data = READ_ONCE(sqe->user_data); req->io = NULL; |