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| author | Pavel Begunkov <asml.silence@gmail.com> | 2021-10-06 16:06:46 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-10-19 05:49:55 -0600 |
| commit | 6d63416dc57eb27a3d35e7b7526e9915479d7eff (patch) | |
| tree | 07f221f413e0fcb79b82780a985d6414d7f566c0 /fs/io_uring.c | |
| parent | 54daa9b2d80ab35824464b35a99f716e1cdf2ccb (diff) | |
| download | lwn-6d63416dc57eb27a3d35e7b7526e9915479d7eff.tar.gz lwn-6d63416dc57eb27a3d35e7b7526e9915479d7eff.zip | |
io_uring: optimise plugging
Plugging is only needed with requests that also need a file, so hide
plugging under a ->needs_file check. Also, place ->needs_file and ->plug
bits into the same byte of io_op_defs, it may matter for compilers, e.g.
only with the change a tested one decided to optimise two memory testb
into a more with two register testb.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1600d1287bb7d16451d4ef3343252787a5314927.1633532552.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs/io_uring.c')
| -rw-r--r-- | fs/io_uring.c | 32 |
1 files changed, 16 insertions, 16 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index 44946711fe62..7759fabf9ae0 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -894,12 +894,12 @@ struct io_defer_entry { struct io_op_def { /* needs req->file assigned */ unsigned needs_file : 1; + /* should block plug */ + unsigned plug : 1; /* hash wq insertion if file is a regular file */ unsigned hash_reg_file : 1; /* unbound wq insertion if file is a non-regular file */ unsigned unbound_nonreg_file : 1; - /* opcode is not supported by this kernel */ - unsigned not_supported : 1; /* set if opcode supports polled "wait" */ unsigned pollin : 1; unsigned pollout : 1; @@ -907,8 +907,8 @@ struct io_op_def { unsigned buffer_select : 1; /* do prep async if is going to be punted */ unsigned needs_async_setup : 1; - /* should block plug */ - unsigned plug : 1; + /* opcode is not supported by this kernel */ + unsigned not_supported : 1; /* size of async data needed, if any */ unsigned short async_size; }; @@ -6978,7 +6978,6 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req, const struct io_uring_sqe *sqe) __must_hold(&ctx->uring_lock) { - struct io_submit_state *state; unsigned int sqe_flags; int personality; @@ -7025,19 +7024,20 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req, get_cred(req->creds); req->flags |= REQ_F_CREDS; } - state = &ctx->submit_state; - - /* - * Plug now if we have more than 1 IO left after this, and the target - * is potentially a read/write to block based storage. - */ - if (state->need_plug && io_op_defs[req->opcode].plug) { - blk_start_plug(&state->plug); - state->plug_started = true; - state->need_plug = false; - } if (io_op_defs[req->opcode].needs_file) { + struct io_submit_state *state = &ctx->submit_state; + + /* + * Plug now if we have more than 2 IO left after this, and the + * target is potentially a read/write to block based storage. + */ + if (state->need_plug && io_op_defs[req->opcode].plug) { + state->plug_started = true; + state->need_plug = false; + blk_start_plug(&state->plug); + } + req->file = io_file_get(ctx, req, READ_ONCE(sqe->fd), (sqe_flags & IOSQE_FIXED_FILE)); if (unlikely(!req->file)) |