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| author | Pavel Begunkov <asml.silence@gmail.com> | 2020-10-18 12:17:40 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-10-19 22:29:29 +0300 |
| commit | 2c3bac6dd6c7af4cb38d1a67cafd29e96ba1fea7 (patch) | |
| tree | 07607f8885f070cb722cad8c7445de989ff7ad23 /fs | |
| parent | d148ca4b07d05656f3b25b662f2283c4d98e7299 (diff) | |
| download | linux-2c3bac6dd6c7af4cb38d1a67cafd29e96ba1fea7.tar.xz | |
io_uring: make cached_cq_overflow non atomic_t
ctx->cached_cq_overflow is changed only under completion_lock. Convert
it from atomic_t to just int, and mark all places when it's read without
lock with READ_ONCE, which guarantees atomicity (relaxed ordering).
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 | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index dce73e40eecb..620a11f9795a 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -277,7 +277,7 @@ struct io_ring_ctx { unsigned sq_mask; unsigned sq_thread_idle; unsigned cached_sq_dropped; - atomic_t cached_cq_overflow; + unsigned cached_cq_overflow; unsigned long sq_check_overflow; struct list_head defer_list; @@ -1179,7 +1179,7 @@ static bool req_need_defer(struct io_kiocb *req, u32 seq) struct io_ring_ctx *ctx = req->ctx; return seq != ctx->cached_cq_tail - + atomic_read(&ctx->cached_cq_overflow); + + READ_ONCE(ctx->cached_cq_overflow); } return false; @@ -1624,8 +1624,9 @@ static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force, WRITE_ONCE(cqe->res, req->result); WRITE_ONCE(cqe->flags, req->compl.cflags); } else { + ctx->cached_cq_overflow++; WRITE_ONCE(ctx->rings->cq_overflow, - atomic_inc_return(&ctx->cached_cq_overflow)); + ctx->cached_cq_overflow); } } @@ -1667,8 +1668,8 @@ static void __io_cqring_fill_event(struct io_kiocb *req, long res, long cflags) * then we cannot store the request for later flushing, we need * to drop it on the floor. */ - WRITE_ONCE(ctx->rings->cq_overflow, - atomic_inc_return(&ctx->cached_cq_overflow)); + ctx->cached_cq_overflow++; + WRITE_ONCE(ctx->rings->cq_overflow, ctx->cached_cq_overflow); } else { if (list_empty(&ctx->cq_overflow_list)) { set_bit(0, &ctx->sq_check_overflow); |