io_uring: switch cancel_hash to use per entry spinlock
Add a new io_hash_bucket structure so that each bucket in cancel_hash
has separate spinlock. Use per entry lock for cancel_hash, this removes
some completion lock invocation and remove contension between different
cancel_hash entries.
Signed-off-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/05d1e135b0c8bce9d1441e6346776589e5783e26.1655371007.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/io_uring/cancel.c b/io_uring/cancel.c
index 83cceb5..6f28883 100644
--- a/io_uring/cancel.c
+++ b/io_uring/cancel.c
@@ -93,14 +93,14 @@ int io_try_cancel(struct io_kiocb *req, struct io_cancel_data *cd)
if (!ret)
return 0;
- spin_lock(&ctx->completion_lock);
ret = io_poll_cancel(ctx, cd);
if (ret != -ENOENT)
goto out;
+ spin_lock(&ctx->completion_lock);
if (!(cd->flags & IORING_ASYNC_CANCEL_FD))
ret = io_timeout_cancel(ctx, cd);
-out:
spin_unlock(&ctx->completion_lock);
+out:
return ret;
}
@@ -192,3 +192,13 @@ int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags)
io_req_set_res(req, ret, 0);
return IOU_OK;
}
+
+void init_hash_table(struct io_hash_bucket *hash_table, unsigned size)
+{
+ unsigned int i;
+
+ for (i = 0; i < size; i++) {
+ spin_lock_init(&hash_table[i].lock);
+ INIT_HLIST_HEAD(&hash_table[i].list);
+ }
+}
diff --git a/io_uring/cancel.h b/io_uring/cancel.h
index 4f35d86..556a7dc 100644
--- a/io_uring/cancel.h
+++ b/io_uring/cancel.h
@@ -4,3 +4,9 @@ int io_async_cancel_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags);
int io_try_cancel(struct io_kiocb *req, struct io_cancel_data *cd);
+void init_hash_table(struct io_hash_bucket *hash_table, unsigned size);
+
+struct io_hash_bucket {
+ spinlock_t lock;
+ struct hlist_head list;
+} ____cacheline_aligned_in_smp;
diff --git a/io_uring/fdinfo.c b/io_uring/fdinfo.c
index fcedde4..f941c73 100644
--- a/io_uring/fdinfo.c
+++ b/io_uring/fdinfo.c
@@ -13,6 +13,7 @@
#include "io_uring.h"
#include "sqpoll.h"
#include "fdinfo.h"
+#include "cancel.h"
#ifdef CONFIG_PROC_FS
static __cold int io_uring_show_cred(struct seq_file *m, unsigned int id,
@@ -157,17 +158,19 @@ static __cold void __io_uring_show_fdinfo(struct io_ring_ctx *ctx,
mutex_unlock(&ctx->uring_lock);
seq_puts(m, "PollList:\n");
- spin_lock(&ctx->completion_lock);
for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
- struct hlist_head *list = &ctx->cancel_hash[i];
+ struct io_hash_bucket *hb = &ctx->cancel_hash[i];
struct io_kiocb *req;
- hlist_for_each_entry(req, list, hash_node)
+ spin_lock(&hb->lock);
+ hlist_for_each_entry(req, &hb->list, hash_node)
seq_printf(m, " op=%d, task_works=%d\n", req->opcode,
task_work_pending(req->task));
+ spin_unlock(&hb->lock);
}
seq_puts(m, "CqOverflowList:\n");
+ spin_lock(&ctx->completion_lock);
list_for_each_entry(ocqe, &ctx->cq_overflow_list, list) {
struct io_uring_cqe *cqe = &ocqe->cqe;
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 957a5bc..ac6946e 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -89,6 +89,7 @@
#include "fdinfo.h"
#include "kbuf.h"
#include "rsrc.h"
+#include "cancel.h"
#include "timeout.h"
#include "poll.h"
@@ -260,11 +261,13 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
if (hash_bits <= 0)
hash_bits = 1;
ctx->cancel_hash_bits = hash_bits;
- ctx->cancel_hash = kmalloc((1U << hash_bits) * sizeof(struct hlist_head),
- GFP_KERNEL);
+ ctx->cancel_hash =
+ kmalloc((1U << hash_bits) * sizeof(struct io_hash_bucket),
+ GFP_KERNEL);
if (!ctx->cancel_hash)
goto err;
- __hash_init(ctx->cancel_hash, 1U << hash_bits);
+
+ init_hash_table(ctx->cancel_hash, 1U << hash_bits);
ctx->dummy_ubuf = kzalloc(sizeof(*ctx->dummy_ubuf), GFP_KERNEL);
if (!ctx->dummy_ubuf)
diff --git a/io_uring/io_uring_types.h b/io_uring/io_uring_types.h
index 4576ea8..1f8db2d 100644
--- a/io_uring/io_uring_types.h
+++ b/io_uring/io_uring_types.h
@@ -224,7 +224,7 @@ struct io_ring_ctx {
* manipulate the list, hence no extra locking is needed there.
*/
struct io_wq_work_list iopoll_list;
- struct hlist_head *cancel_hash;
+ struct io_hash_bucket *cancel_hash;
unsigned cancel_hash_bits;
bool poll_multi_queue;
diff --git a/io_uring/poll.c b/io_uring/poll.c
index fdb6b11..1511a26 100644
--- a/io_uring/poll.c
+++ b/io_uring/poll.c
@@ -19,6 +19,7 @@
#include "opdef.h"
#include "kbuf.h"
#include "poll.h"
+#include "cancel.h"
struct io_poll_update {
struct file *file;
@@ -73,10 +74,22 @@ static struct io_poll *io_poll_get_single(struct io_kiocb *req)
static void io_poll_req_insert(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
- struct hlist_head *list;
+ u32 index = hash_long(req->cqe.user_data, ctx->cancel_hash_bits);
+ struct io_hash_bucket *hb = &ctx->cancel_hash[index];
- list = &ctx->cancel_hash[hash_long(req->cqe.user_data, ctx->cancel_hash_bits)];
- hlist_add_head(&req->hash_node, list);
+ spin_lock(&hb->lock);
+ hlist_add_head(&req->hash_node, &hb->list);
+ spin_unlock(&hb->lock);
+}
+
+static void io_poll_req_delete(struct io_kiocb *req, struct io_ring_ctx *ctx)
+{
+ u32 index = hash_long(req->cqe.user_data, ctx->cancel_hash_bits);
+ spinlock_t *lock = &ctx->cancel_hash[index].lock;
+
+ spin_lock(lock);
+ hash_del(&req->hash_node);
+ spin_unlock(lock);
}
static void io_init_poll_iocb(struct io_poll *poll, __poll_t events,
@@ -220,8 +233,8 @@ static void io_poll_task_func(struct io_kiocb *req, bool *locked)
}
io_poll_remove_entries(req);
+ io_poll_req_delete(req, ctx);
spin_lock(&ctx->completion_lock);
- hash_del(&req->hash_node);
req->cqe.flags = 0;
__io_req_complete_post(req);
io_commit_cqring(ctx);
@@ -231,7 +244,6 @@ static void io_poll_task_func(struct io_kiocb *req, bool *locked)
static void io_apoll_task_func(struct io_kiocb *req, bool *locked)
{
- struct io_ring_ctx *ctx = req->ctx;
int ret;
ret = io_poll_check_events(req, locked);
@@ -239,9 +251,7 @@ static void io_apoll_task_func(struct io_kiocb *req, bool *locked)
return;
io_poll_remove_entries(req);
- spin_lock(&ctx->completion_lock);
- hash_del(&req->hash_node);
- spin_unlock(&ctx->completion_lock);
+ io_poll_req_delete(req, req->ctx);
if (!ret)
io_req_task_submit(req, locked);
@@ -437,9 +447,7 @@ static int __io_arm_poll_handler(struct io_kiocb *req,
return 0;
}
- spin_lock(&ctx->completion_lock);
io_poll_req_insert(req);
- spin_unlock(&ctx->completion_lock);
if (mask && (poll->events & EPOLLET)) {
/* can't multishot if failed, just queue the event we've got */
@@ -540,32 +548,31 @@ __cold bool io_poll_remove_all(struct io_ring_ctx *ctx, struct task_struct *tsk,
bool found = false;
int i;
- spin_lock(&ctx->completion_lock);
for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
- struct hlist_head *list;
+ struct io_hash_bucket *hb = &ctx->cancel_hash[i];
- list = &ctx->cancel_hash[i];
- hlist_for_each_entry_safe(req, tmp, list, hash_node) {
+ spin_lock(&hb->lock);
+ hlist_for_each_entry_safe(req, tmp, &hb->list, hash_node) {
if (io_match_task_safe(req, tsk, cancel_all)) {
hlist_del_init(&req->hash_node);
io_poll_cancel_req(req);
found = true;
}
}
+ spin_unlock(&hb->lock);
}
- spin_unlock(&ctx->completion_lock);
return found;
}
static struct io_kiocb *io_poll_find(struct io_ring_ctx *ctx, bool poll_only,
struct io_cancel_data *cd)
- __must_hold(&ctx->completion_lock)
{
- struct hlist_head *list;
struct io_kiocb *req;
+ u32 index = hash_long(cd->data, ctx->cancel_hash_bits);
+ struct io_hash_bucket *hb = &ctx->cancel_hash[index];
- list = &ctx->cancel_hash[hash_long(cd->data, ctx->cancel_hash_bits)];
- hlist_for_each_entry(req, list, hash_node) {
+ spin_lock(&hb->lock);
+ hlist_for_each_entry(req, &hb->list, hash_node) {
if (cd->data != req->cqe.user_data)
continue;
if (poll_only && req->opcode != IORING_OP_POLL_ADD)
@@ -577,21 +584,21 @@ static struct io_kiocb *io_poll_find(struct io_ring_ctx *ctx, bool poll_only,
}
return req;
}
+ spin_unlock(&hb->lock);
return NULL;
}
static struct io_kiocb *io_poll_file_find(struct io_ring_ctx *ctx,
struct io_cancel_data *cd)
- __must_hold(&ctx->completion_lock)
{
struct io_kiocb *req;
int i;
for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
- struct hlist_head *list;
+ struct io_hash_bucket *hb = &ctx->cancel_hash[i];
- list = &ctx->cancel_hash[i];
- hlist_for_each_entry(req, list, hash_node) {
+ spin_lock(&hb->lock);
+ hlist_for_each_entry(req, &hb->list, hash_node) {
if (!(cd->flags & IORING_ASYNC_CANCEL_ANY) &&
req->file != cd->file)
continue;
@@ -600,12 +607,12 @@ static struct io_kiocb *io_poll_file_find(struct io_ring_ctx *ctx,
req->work.cancel_seq = cd->seq;
return req;
}
+ spin_unlock(&hb->lock);
}
return NULL;
}
static bool io_poll_disarm(struct io_kiocb *req)
- __must_hold(&ctx->completion_lock)
{
if (!io_poll_get_ownership(req))
return false;
@@ -615,17 +622,23 @@ static bool io_poll_disarm(struct io_kiocb *req)
}
int io_poll_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd)
- __must_hold(&ctx->completion_lock)
{
struct io_kiocb *req;
+ u32 index;
+ spinlock_t *lock;
if (cd->flags & (IORING_ASYNC_CANCEL_FD|IORING_ASYNC_CANCEL_ANY))
req = io_poll_file_find(ctx, cd);
else
req = io_poll_find(ctx, false, cd);
- if (!req)
+ if (!req) {
return -ENOENT;
+ } else {
+ index = hash_long(req->cqe.user_data, ctx->cancel_hash_bits);
+ lock = &ctx->cancel_hash[index].lock;
+ }
io_poll_cancel_req(req);
+ spin_unlock(lock);
return 0;
}
@@ -719,18 +732,23 @@ int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags)
struct io_poll_update *poll_update = io_kiocb_to_cmd(req);
struct io_cancel_data cd = { .data = poll_update->old_user_data, };
struct io_ring_ctx *ctx = req->ctx;
+ u32 index = hash_long(cd.data, ctx->cancel_hash_bits);
+ spinlock_t *lock = &ctx->cancel_hash[index].lock;
struct io_kiocb *preq;
int ret2, ret = 0;
bool locked;
- spin_lock(&ctx->completion_lock);
preq = io_poll_find(ctx, true, &cd);
- if (!preq || !io_poll_disarm(preq)) {
- spin_unlock(&ctx->completion_lock);
- ret = preq ? -EALREADY : -ENOENT;
+ if (!preq) {
+ ret = -ENOENT;
goto out;
}
- spin_unlock(&ctx->completion_lock);
+ ret2 = io_poll_disarm(preq);
+ spin_unlock(lock);
+ if (!ret2) {
+ ret = -EALREADY;
+ goto out;
+ }
if (poll_update->update_events || poll_update->update_user_data) {
/* only mask one event flags, keep behavior flags */
