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Message-ID: <20250128133927.3989681-8-max.kellermann@ionos.com>
Date: Tue, 28 Jan 2025 14:39:26 +0100
From: Max Kellermann <max.kellermann@...os.com>
To: axboe@...nel.dk,
asml.silence@...il.com,
io-uring@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: Max Kellermann <max.kellermann@...os.com>
Subject: [PATCH 7/8] io_uring: cache io_kiocb->flags in variable
This eliminates several redundant reads, some of which probably cannot
be optimized away by the compiler.
Signed-off-by: Max Kellermann <max.kellermann@...os.com>
---
io_uring/io_uring.c | 59 +++++++++++++++++++++++++++------------------
1 file changed, 35 insertions(+), 24 deletions(-)
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 7bfbc7c22367..137c2066c5a3 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -391,28 +391,30 @@ static bool req_need_defer(struct io_kiocb *req, u32 seq)
static void io_clean_op(struct io_kiocb *req)
{
- if (req->flags & REQ_F_BUFFER_SELECTED) {
+ const unsigned int req_flags = req->flags;
+
+ if (req_flags & REQ_F_BUFFER_SELECTED) {
spin_lock(&req->ctx->completion_lock);
io_kbuf_drop(req);
spin_unlock(&req->ctx->completion_lock);
}
- if (req->flags & REQ_F_NEED_CLEANUP) {
+ if (req_flags & REQ_F_NEED_CLEANUP) {
const struct io_cold_def *def = &io_cold_defs[req->opcode];
if (def->cleanup)
def->cleanup(req);
}
- if ((req->flags & REQ_F_POLLED) && req->apoll) {
+ if ((req_flags & REQ_F_POLLED) && req->apoll) {
kfree(req->apoll->double_poll);
kfree(req->apoll);
req->apoll = NULL;
}
- if (req->flags & REQ_F_INFLIGHT)
+ if (req_flags & REQ_F_INFLIGHT)
atomic_dec(&req->tctx->inflight_tracked);
- if (req->flags & REQ_F_CREDS)
+ if (req_flags & REQ_F_CREDS)
put_cred(req->creds);
- if (req->flags & REQ_F_ASYNC_DATA) {
+ if (req_flags & REQ_F_ASYNC_DATA) {
kfree(req->async_data);
req->async_data = NULL;
}
@@ -453,31 +455,37 @@ static noinline void __io_arm_ltimeout(struct io_kiocb *req)
io_queue_linked_timeout(__io_prep_linked_timeout(req));
}
-static inline void io_arm_ltimeout(struct io_kiocb *req)
+static inline void _io_arm_ltimeout(struct io_kiocb *req, unsigned int req_flags)
{
- if (unlikely(req->flags & REQ_F_ARM_LTIMEOUT))
+ if (unlikely(req_flags & REQ_F_ARM_LTIMEOUT))
__io_arm_ltimeout(req);
}
+static inline void io_arm_ltimeout(struct io_kiocb *req)
+{
+ _io_arm_ltimeout(req, req->flags);
+}
+
static void io_prep_async_work(struct io_kiocb *req)
{
+ unsigned int req_flags = req->flags;
const struct io_issue_def *def = &io_issue_defs[req->opcode];
struct io_ring_ctx *ctx = req->ctx;
- if (!(req->flags & REQ_F_CREDS)) {
- req->flags |= REQ_F_CREDS;
+ if (!(req_flags & REQ_F_CREDS)) {
+ req_flags = req->flags |= REQ_F_CREDS;
req->creds = get_current_cred();
}
req->work.list.next = NULL;
atomic_set(&req->work.flags, 0);
- if (req->flags & REQ_F_FORCE_ASYNC)
+ if (req_flags & REQ_F_FORCE_ASYNC)
atomic_or(IO_WQ_WORK_CONCURRENT, &req->work.flags);
- if (req->file && !(req->flags & REQ_F_FIXED_FILE))
- req->flags |= io_file_get_flags(req->file);
+ if (req->file && !(req_flags & REQ_F_FIXED_FILE))
+ req_flags = req->flags |= io_file_get_flags(req->file);
- if (req->file && (req->flags & REQ_F_ISREG)) {
+ if (req->file && (req_flags & REQ_F_ISREG)) {
bool should_hash = def->hash_reg_file;
/* don't serialize this request if the fs doesn't need it */
@@ -1703,13 +1711,14 @@ static __cold void io_drain_req(struct io_kiocb *req)
spin_unlock(&ctx->completion_lock);
}
-static bool io_assign_file(struct io_kiocb *req, const struct io_issue_def *def,
+static bool io_assign_file(struct io_kiocb *req, unsigned int req_flags,
+ const struct io_issue_def *def,
unsigned int issue_flags)
{
if (req->file || !def->needs_file)
return true;
- if (req->flags & REQ_F_FIXED_FILE)
+ if (req_flags & REQ_F_FIXED_FILE)
req->file = io_file_get_fixed(req, req->cqe.fd, issue_flags);
else
req->file = io_file_get_normal(req, req->cqe.fd);
@@ -1719,14 +1728,15 @@ static bool io_assign_file(struct io_kiocb *req, const struct io_issue_def *def,
static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
{
+ const unsigned int req_flags = req->flags;
const struct io_issue_def *def = &io_issue_defs[req->opcode];
const struct cred *creds = NULL;
int ret;
- if (unlikely(!io_assign_file(req, def, issue_flags)))
+ if (unlikely(!io_assign_file(req, req_flags, def, issue_flags)))
return -EBADF;
- if (unlikely((req->flags & REQ_F_CREDS) && req->creds != current_cred()))
+ if (unlikely((req_flags & REQ_F_CREDS) && req->creds != current_cred()))
creds = override_creds(req->creds);
if (!def->audit_skip)
@@ -1783,18 +1793,19 @@ struct io_wq_work *io_wq_free_work(struct io_wq_work *work)
void io_wq_submit_work(struct io_wq_work *work)
{
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
+ const unsigned int req_flags = req->flags;
const struct io_issue_def *def = &io_issue_defs[req->opcode];
unsigned int issue_flags = IO_URING_F_UNLOCKED | IO_URING_F_IOWQ;
bool needs_poll = false;
int ret = 0, err = -ECANCELED;
/* one will be dropped by ->io_wq_free_work() after returning to io-wq */
- if (!(req->flags & REQ_F_REFCOUNT))
+ if (!(req_flags & REQ_F_REFCOUNT))
__io_req_set_refcount(req, 2);
else
req_ref_get(req);
- io_arm_ltimeout(req);
+ _io_arm_ltimeout(req, req_flags);
/* either cancelled or io-wq is dying, so don't touch tctx->iowq */
if (atomic_read(&work->flags) & IO_WQ_WORK_CANCEL) {
@@ -1802,7 +1813,7 @@ void io_wq_submit_work(struct io_wq_work *work)
io_req_task_queue_fail(req, err);
return;
}
- if (!io_assign_file(req, def, issue_flags)) {
+ if (!io_assign_file(req, req_flags, def, issue_flags)) {
err = -EBADF;
atomic_or(IO_WQ_WORK_CANCEL, &work->flags);
goto fail;
@@ -1816,7 +1827,7 @@ void io_wq_submit_work(struct io_wq_work *work)
* Don't allow any multishot execution from io-wq. It's more restrictive
* than necessary and also cleaner.
*/
- if (req->flags & REQ_F_APOLL_MULTISHOT) {
+ if (req_flags & REQ_F_APOLL_MULTISHOT) {
err = -EBADFD;
if (!io_file_can_poll(req))
goto fail;
@@ -1831,7 +1842,7 @@ void io_wq_submit_work(struct io_wq_work *work)
}
}
- if (req->flags & REQ_F_FORCE_ASYNC) {
+ if (req_flags & REQ_F_FORCE_ASYNC) {
bool opcode_poll = def->pollin || def->pollout;
if (opcode_poll && io_file_can_poll(req)) {
@@ -1849,7 +1860,7 @@ void io_wq_submit_work(struct io_wq_work *work)
* If REQ_F_NOWAIT is set, then don't wait or retry with
* poll. -EAGAIN is final for that case.
*/
- if (req->flags & REQ_F_NOWAIT)
+ if (req_flags & REQ_F_NOWAIT)
break;
/*
--
2.45.2
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