From: Pavel Begunkov <[email protected]>
To: Jens Axboe <[email protected]>, [email protected]
Subject: [PATCH 05/12] io_uring: don't cache number of dropped SQEs
Date: Mon, 14 Jun 2021 23:37:24 +0100 [thread overview]
Message-ID: <088aceb2707a534d531e2770267c4498e0507cc1.1623709150.git.asml.silence@gmail.com> (raw)
In-Reply-To: <[email protected]>
Kill ->cached_sq_dropped and wire DRAIN sequence number correction via
->cq_extra, which is there exactly for that purpose. User visible
dropped counter will be populated by incrementing it instead of keeping
a copy, similarly as it was done not so long ago with cq_overflow.
Signed-off-by: Pavel Begunkov <[email protected]>
---
fs/io_uring.c | 12 +++++-------
1 file changed, 5 insertions(+), 7 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 3baacfe2c9b7..6dd14f4aa5f1 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -370,7 +370,6 @@ struct io_ring_ctx {
struct io_uring_sqe *sq_sqes;
unsigned cached_sq_head;
unsigned sq_entries;
- unsigned cached_sq_dropped;
unsigned long sq_check_overflow;
struct list_head defer_list;
@@ -5994,13 +5993,11 @@ static u32 io_get_sequence(struct io_kiocb *req)
{
struct io_kiocb *pos;
struct io_ring_ctx *ctx = req->ctx;
- u32 total_submitted, nr_reqs = 0;
+ u32 nr_reqs = 0;
io_for_each_link(pos, req)
nr_reqs++;
-
- total_submitted = ctx->cached_sq_head - ctx->cached_sq_dropped;
- return total_submitted - nr_reqs;
+ return ctx->cached_sq_head - nr_reqs;
}
static int io_req_defer(struct io_kiocb *req)
@@ -6701,8 +6698,9 @@ static const struct io_uring_sqe *io_get_sqe(struct io_ring_ctx *ctx)
return &ctx->sq_sqes[head];
/* drop invalid entries */
- ctx->cached_sq_dropped++;
- WRITE_ONCE(ctx->rings->sq_dropped, ctx->cached_sq_dropped);
+ ctx->cq_extra--;
+ WRITE_ONCE(ctx->rings->sq_dropped,
+ READ_ONCE(ctx->rings->sq_dropped) + 1);
return NULL;
}
--
2.31.1
next prev parent reply other threads:[~2021-06-14 22:38 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-14 22:37 [PATCH 5.14 00/12] for-next optimisations Pavel Begunkov
2021-06-14 22:37 ` [PATCH 01/12] io_uring: keep SQ pointers in a single cacheline Pavel Begunkov
2021-06-14 22:37 ` [PATCH 02/12] io_uring: move ctx->flags from SQ cacheline Pavel Begunkov
2021-06-14 22:37 ` [PATCH 03/12] io_uring: shuffle more fields into SQ ctx section Pavel Begunkov
2021-06-14 22:37 ` [PATCH 04/12] io_uring: refactor io_get_sqe() Pavel Begunkov
2021-06-14 22:37 ` Pavel Begunkov [this message]
2021-06-14 22:37 ` [PATCH 06/12] io_uring: optimise completion timeout flushing Pavel Begunkov
2021-06-14 22:37 ` [PATCH 07/12] io_uring: small io_submit_sqe() optimisation Pavel Begunkov
2021-06-14 22:37 ` [PATCH 08/12] io_uring: clean up check_overflow flag Pavel Begunkov
2021-06-14 22:37 ` [PATCH 09/12] io_uring: wait heads renaming Pavel Begunkov
2021-06-14 22:37 ` [PATCH 10/12] io_uring: move uring_lock location Pavel Begunkov
2021-06-14 22:37 ` [PATCH 11/12] io_uring: refactor io_req_defer() Pavel Begunkov
2021-06-14 22:37 ` [PATCH 12/12] io_uring: optimise non-drain path Pavel Begunkov
2021-06-15 12:27 ` [PATCH 5.14 00/12] for-next optimisations Pavel Begunkov
2021-06-15 21:38 ` Jens Axboe
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