Switch the normal task_work to io_wq_work_list as well, to both unify
with defer task_work, but also to avoid needing to reverse the ordering
of the list when running it.
Note that this still keeps the manual retry list for SQPOLL task_work.
That could go away as well, as now the task_work list is fully ordered
and SQPOLL could just leave entries on there when it chops up the
running of the list.
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
---
include/linux/io_uring_types.h | 14 ++-
io_uring/io_uring.c | 167 ++++++++++++++++++++-------------
io_uring/io_uring.h | 6 +-
io_uring/sqpoll.c | 8 +-
io_uring/tctx.c | 3 +-
5 files changed, 116 insertions(+), 82 deletions(-)
diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h
index e9ba99cb0ed0..7ddac4d1d4b3 100644
--- a/include/linux/io_uring_types.h
+++ b/include/linux/io_uring_types.h
@@ -102,7 +102,8 @@ struct io_uring_task {
struct percpu_counter inflight;
struct { /* task_work */
- struct llist_head task_list;
+ struct io_wq_work_list task_list;
+ spinlock_t task_lock;
struct callback_head task_work;
} ____cacheline_aligned_in_smp;
};
@@ -390,8 +391,9 @@ struct io_ring_ctx {
struct mm_struct *mm_account;
/* ctx exit and cancelation */
- struct llist_head fallback_llist;
- struct delayed_work fallback_work;
+ struct io_wq_work_list fallback_list;
+ spinlock_t fallback_lock;
+ struct work_struct fallback_work;
struct work_struct exit_work;
struct list_head tctx_list;
struct completion ref_comp;
@@ -567,11 +569,7 @@ enum {
typedef void (*io_req_tw_func_t)(struct io_kiocb *req, struct io_tw_state *ts);
struct io_task_work {
- /* DEFER_TASKRUN uses work_node, regular task_work node */
- union {
- struct io_wq_work_node work_node;
- struct llist_node node;
- };
+ struct io_wq_work_node node;
io_req_tw_func_t func;
};
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index b7eb962e9872..3bb93c77ac3f 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -245,15 +245,26 @@ static __cold void io_ring_ctx_ref_free(struct percpu_ref *ref)
static __cold void io_fallback_req_func(struct work_struct *work)
{
struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx,
- fallback_work.work);
- struct llist_node *node = llist_del_all(&ctx->fallback_llist);
- struct io_kiocb *req, *tmp;
+ fallback_work);
+ struct io_wq_work_node *node;
struct io_tw_state ts = {};
+ struct io_wq_work_list list;
+
+ spin_lock_irq(&ctx->fallback_lock);
+ list = ctx->fallback_list;
+ INIT_WQ_LIST(&ctx->fallback_list);
+ spin_unlock_irq(&ctx->fallback_lock);
percpu_ref_get(&ctx->refs);
mutex_lock(&ctx->uring_lock);
- llist_for_each_entry_safe(req, tmp, node, io_task_work.node)
+ node = list.first;
+ while (node) {
+ struct io_kiocb *req;
+
+ req = container_of(node, struct io_kiocb, io_task_work.node);
+ node = node->next;
req->io_task_work.func(req, &ts);
+ }
io_submit_flush_completions(ctx);
mutex_unlock(&ctx->uring_lock);
percpu_ref_put(&ctx->refs);
@@ -347,7 +358,9 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
#ifdef CONFIG_FUTEX
INIT_HLIST_HEAD(&ctx->futex_list);
#endif
- INIT_DELAYED_WORK(&ctx->fallback_work, io_fallback_req_func);
+ INIT_WORK(&ctx->fallback_work, io_fallback_req_func);
+ INIT_WQ_LIST(&ctx->fallback_list);
+ spin_lock_init(&ctx->fallback_lock);
INIT_WQ_LIST(&ctx->submit_state.compl_reqs);
INIT_HLIST_HEAD(&ctx->cancelable_uring_cmd);
io_napi_init(ctx);
@@ -1033,15 +1046,15 @@ static void ctx_flush_and_put(struct io_ring_ctx *ctx, struct io_tw_state *ts)
* If more entries than max_entries are available, stop processing once this
* is reached and return the rest of the list.
*/
-struct llist_node *io_handle_tw_list(struct llist_node *node,
- unsigned int *count,
- unsigned int max_entries)
+struct io_wq_work_node *io_handle_tw_list(struct io_wq_work_node *node,
+ unsigned int *count,
+ unsigned int max_entries)
{
struct io_ring_ctx *ctx = NULL;
struct io_tw_state ts = { };
do {
- struct llist_node *next = node->next;
+ struct io_wq_work_node *next = node->next;
struct io_kiocb *req = container_of(node, struct io_kiocb,
io_task_work.node);
@@ -1067,55 +1080,84 @@ struct llist_node *io_handle_tw_list(struct llist_node *node,
return node;
}
-static __cold void __io_fallback_tw(struct io_kiocb *req, bool sync,
- struct io_ring_ctx **last_ctx)
+static __cold void __io_fallback_schedule(struct io_ring_ctx *ctx,
+ struct io_wq_work_list *list,
+ bool sync)
{
- if (sync && *last_ctx != req->ctx) {
- if (*last_ctx) {
- flush_delayed_work(&(*last_ctx)->fallback_work);
- percpu_ref_put(&(*last_ctx)->refs);
- }
- *last_ctx = req->ctx;
- percpu_ref_get(&(*last_ctx)->refs);
- }
- if (llist_add(&req->io_task_work.node, &req->ctx->fallback_llist))
- schedule_delayed_work(&req->ctx->fallback_work, 1);
+ bool kick_work = true;
+ unsigned long flags;
+
+ spin_lock_irqsave(&ctx->fallback_lock, flags);
+ kick_work = !wq_list_splice_list(list, &ctx->fallback_list);
+ spin_unlock_irqrestore(&ctx->fallback_lock, flags);
+ if (kick_work)
+ schedule_work(&ctx->fallback_work);
+
+ if (sync)
+ flush_work(&ctx->fallback_work);
+ percpu_ref_put(&ctx->refs);
}
-static void io_fallback_tw(struct io_uring_task *tctx, bool sync)
+static void __io_fallback_tw(struct io_wq_work_list *list, spinlock_t *lock,
+ bool sync)
{
- struct llist_node *node = llist_del_all(&tctx->task_list);
+ struct io_wq_work_list local_list, ctx_list;
struct io_ring_ctx *last_ctx = NULL;
+ struct io_wq_work_node *node;
struct io_kiocb *req;
+ unsigned long flags;
+
+ spin_lock_irqsave(lock, flags);
+ local_list = *list;
+ INIT_WQ_LIST(list);
+ spin_unlock_irqrestore(lock, flags);
+ INIT_WQ_LIST(&ctx_list);
+ node = local_list.first;
while (node) {
+ struct io_wq_work_node *next = node->next;
+
req = container_of(node, struct io_kiocb, io_task_work.node);
- node = node->next;
- __io_fallback_tw(req, sync, &last_ctx);
+ if (last_ctx != req->ctx) {
+ if (last_ctx)
+ __io_fallback_schedule(last_ctx, &ctx_list, sync);
+ last_ctx = req->ctx;
+ percpu_ref_get(&last_ctx->refs);
+ }
+ wq_list_add_tail(node, &ctx_list);
+ node = next;
}
- if (last_ctx) {
- flush_delayed_work(&last_ctx->fallback_work);
- percpu_ref_put(&last_ctx->refs);
- }
+ if (last_ctx)
+ __io_fallback_schedule(last_ctx, &ctx_list, sync);
+}
+
+static void io_fallback_tw(struct io_uring_task *tctx, bool sync)
+{
+ __io_fallback_tw(&tctx->task_list, &tctx->task_lock, sync);
}
-struct llist_node *tctx_task_work_run(struct io_uring_task *tctx,
- unsigned int max_entries,
- unsigned int *count)
+struct io_wq_work_node *tctx_task_work_run(struct io_uring_task *tctx,
+ unsigned int max_entries,
+ unsigned int *count)
{
- struct llist_node *node;
+ struct io_wq_work_node *node;
if (unlikely(current->flags & PF_EXITING)) {
io_fallback_tw(tctx, true);
return NULL;
}
- node = llist_del_all(&tctx->task_list);
- if (node) {
- node = llist_reverse_order(node);
+ if (!READ_ONCE(tctx->task_list.first))
+ return NULL;
+
+ spin_lock_irq(&tctx->task_lock);
+ node = tctx->task_list.first;
+ INIT_WQ_LIST(&tctx->task_list);
+ spin_unlock_irq(&tctx->task_lock);
+
+ if (node)
node = io_handle_tw_list(node, count, max_entries);
- }
/* relaxed read is enough as only the task itself sets ->in_cancel */
if (unlikely(atomic_read(&tctx->in_cancel)))
@@ -1128,13 +1170,11 @@ struct llist_node *tctx_task_work_run(struct io_uring_task *tctx,
void tctx_task_work(struct callback_head *cb)
{
struct io_uring_task *tctx;
- struct llist_node *ret;
unsigned int count = 0;
tctx = container_of(cb, struct io_uring_task, task_work);
- ret = tctx_task_work_run(tctx, UINT_MAX, &count);
- /* can't happen */
- WARN_ON_ONCE(ret);
+ if (tctx_task_work_run(tctx, UINT_MAX, &count))
+ WARN_ON_ONCE(1);
}
static inline void io_req_local_work_add(struct io_kiocb *req,
@@ -1155,7 +1195,7 @@ static inline void io_req_local_work_add(struct io_kiocb *req,
tw_flags &= ~IOU_F_TWQ_LAZY_WAKE;
spin_lock_irqsave(&ctx->work_lock, flags);
- wq_list_add_tail(&req->io_task_work.work_node, &ctx->work_list);
+ wq_list_add_tail(&req->io_task_work.node, &ctx->work_list);
nr_tw_prev = ctx->work_items++;
spin_unlock_irqrestore(&ctx->work_lock, flags);
@@ -1192,9 +1232,16 @@ static void io_req_normal_work_add(struct io_kiocb *req)
{
struct io_uring_task *tctx = req->tctx;
struct io_ring_ctx *ctx = req->ctx;
+ unsigned long flags;
+ bool was_empty;
+
+ spin_lock_irqsave(&tctx->task_lock, flags);
+ was_empty = tctx->task_list.first == NULL;
+ wq_list_add_tail(&req->io_task_work.node, &tctx->task_list);
+ spin_unlock_irqrestore(&tctx->task_lock, flags);
/* task_work already pending, we're done */
- if (!llist_add(&req->io_task_work.node, &tctx->task_list))
+ if (!was_empty)
return;
if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
@@ -1233,27 +1280,13 @@ void io_req_task_work_add_remote(struct io_kiocb *req, struct io_ring_ctx *ctx,
static void __cold io_move_task_work_from_local(struct io_ring_ctx *ctx)
{
- struct io_ring_ctx *last_ctx = NULL;
- struct io_wq_work_node *node;
- unsigned long flags;
-
- spin_lock_irqsave(&ctx->work_lock, flags);
- node = ctx->work_list.first;
- INIT_WQ_LIST(&ctx->work_list);
- ctx->work_items = 0;
- spin_unlock_irqrestore(&ctx->work_lock, flags);
-
- while (node) {
- struct io_kiocb *req;
-
- req = container_of(node, struct io_kiocb, io_task_work.work_node);
- node = node->next;
- __io_fallback_tw(req, false, &last_ctx);
- }
- if (last_ctx) {
- flush_delayed_work(&last_ctx->fallback_work);
- percpu_ref_put(&last_ctx->refs);
- }
+ /*
+ * __io_fallback_tw() handles lists that can have multiple
+ * rings in it, which isn't the case here. But it'll work just
+ * fine, so use it anyway rather than have a special case for
+ * just a single ctx.
+ */
+ __io_fallback_tw(&ctx->work_list, &ctx->work_lock, false);
}
static bool io_run_local_work_continue(struct io_ring_ctx *ctx, int events,
@@ -1292,7 +1325,7 @@ static int __io_run_local_work(struct io_ring_ctx *ctx, struct io_tw_state *ts,
while (node) {
struct io_kiocb *req = container_of(node, struct io_kiocb,
- io_task_work.work_node);
+ io_task_work.node);
node = node->next;
INDIRECT_CALL_2(req->io_task_work.func,
io_poll_task_func, io_req_rw_complete,
@@ -2967,7 +3000,7 @@ static __cold void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
io_unregister_personality(ctx, index);
mutex_unlock(&ctx->uring_lock);
- flush_delayed_work(&ctx->fallback_work);
+ flush_work(&ctx->fallback_work);
INIT_WORK(&ctx->exit_work, io_ring_exit_work);
/*
@@ -3106,7 +3139,7 @@ static __cold bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
if (tctx)
ret |= io_run_task_work() > 0;
else
- ret |= flush_delayed_work(&ctx->fallback_work);
+ ret |= flush_work(&ctx->fallback_work);
return ret;
}
diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h
index 2fae27803116..0b5181b128aa 100644
--- a/io_uring/io_uring.h
+++ b/io_uring/io_uring.h
@@ -91,8 +91,10 @@ void io_req_task_queue(struct io_kiocb *req);
void io_req_task_complete(struct io_kiocb *req, struct io_tw_state *ts);
void io_req_task_queue_fail(struct io_kiocb *req, int ret);
void io_req_task_submit(struct io_kiocb *req, struct io_tw_state *ts);
-struct llist_node *io_handle_tw_list(struct llist_node *node, unsigned int *count, unsigned int max_entries);
-struct llist_node *tctx_task_work_run(struct io_uring_task *tctx, unsigned int max_entries, unsigned int *count);
+struct io_wq_work_node *io_handle_tw_list(struct io_wq_work_node *node,
+ unsigned int *count, unsigned int max_entries);
+struct io_wq_work_node *tctx_task_work_run(struct io_uring_task *tctx,
+ unsigned int max_entries, unsigned int *count);
void tctx_task_work(struct callback_head *cb);
__cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd);
int io_uring_alloc_task_context(struct task_struct *task,
diff --git a/io_uring/sqpoll.c b/io_uring/sqpoll.c
index 6df5e649c413..615707260f25 100644
--- a/io_uring/sqpoll.c
+++ b/io_uring/sqpoll.c
@@ -221,7 +221,7 @@ static bool io_sqd_handle_event(struct io_sq_data *sqd)
* than we were asked to process. Newly queued task_work isn't run until the
* retry list has been fully processed.
*/
-static unsigned int io_sq_tw(struct llist_node **retry_list, int max_entries)
+static unsigned int io_sq_tw(struct io_wq_work_node **retry_list, int max_entries)
{
struct io_uring_task *tctx = current->io_uring;
unsigned int count = 0;
@@ -239,11 +239,11 @@ static unsigned int io_sq_tw(struct llist_node **retry_list, int max_entries)
return count;
}
-static bool io_sq_tw_pending(struct llist_node *retry_list)
+static bool io_sq_tw_pending(struct io_wq_work_node *retry_list)
{
struct io_uring_task *tctx = current->io_uring;
- return retry_list || !llist_empty(&tctx->task_list);
+ return retry_list || READ_ONCE(tctx->task_list.first);
}
static void io_sq_update_worktime(struct io_sq_data *sqd, struct rusage *start)
@@ -259,7 +259,7 @@ static void io_sq_update_worktime(struct io_sq_data *sqd, struct rusage *start)
static int io_sq_thread(void *data)
{
- struct llist_node *retry_list = NULL;
+ struct io_wq_work_node *retry_list = NULL;
struct io_sq_data *sqd = data;
struct io_ring_ctx *ctx;
struct rusage start;
diff --git a/io_uring/tctx.c b/io_uring/tctx.c
index 503f3ff8bc4f..7155b3c56c85 100644
--- a/io_uring/tctx.c
+++ b/io_uring/tctx.c
@@ -87,7 +87,8 @@ __cold int io_uring_alloc_task_context(struct task_struct *task,
atomic_set(&tctx->in_cancel, 0);
atomic_set(&tctx->inflight_tracked, 0);
task->io_uring = tctx;
- init_llist_head(&tctx->task_list);
+ INIT_WQ_LIST(&tctx->task_list);
+ spin_lock_init(&tctx->task_lock);
init_task_work(&tctx->task_work, tctx_task_work);
return 0;
}
--
2.45.2
