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io_uring: switch cancel_hash to use per entry spinlock

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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>
This commit is contained in:
Hao Xu 2022-06-16 10:22:02 +01:00 committed by Jens Axboe
parent 3654ab0c51
commit 38513c464d
6 changed files with 80 additions and 40 deletions
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14
io_uring/cancel.c
View File

@ -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);
}
}

6
io_uring/cancel.h
View File

@ -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;

9
io_uring/fdinfo.c
View File

@ -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;

9
io_uring/io_uring.c
View File

@ -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)

2
io_uring/io_uring_types.h
View File

@ -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;

80
io_uring/poll.c
View File

@ -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;
}
ret2 = io_poll_disarm(preq);
spin_unlock(lock);
if (!ret2) {
ret = -EALREADY;
goto out;
}
spin_unlock(&ctx->completion_lock);
if (poll_update->update_events || poll_update->update_user_data) {
/* only mask one event flags, keep behavior flags */