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io_uring/rsrc: optimise io_rsrc_data refcounting

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Every struct io_rsrc_node takes a struct io_rsrc_data reference, which
means all rsrc updates do 2 extra atomics. Replace atomics refcounting
with a int as it's all done under ->uring_lock.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/e73c3d6820cf679532696d790b5b8fae23537213.1680576071.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2023-04-04 13:39:56 +01:00 committed by Jens Axboe
parent 1f2c8f610a
commit 757ef4682b
2 changed files with 19 additions and 13 deletions
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30
io_uring/rsrc.c
View File

@ -31,6 +31,11 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
#define IORING_MAX_FIXED_FILES (1U << 20) #define IORING_MAX_FIXED_FILES (1U << 20)
#define IORING_MAX_REG_BUFFERS (1U << 14) #define IORING_MAX_REG_BUFFERS (1U << 14)
static inline bool io_put_rsrc_data_ref(struct io_rsrc_data *rsrc_data)
{
return !--rsrc_data->refs;
}
int __io_account_mem(struct user_struct *user, unsigned long nr_pages) int __io_account_mem(struct user_struct *user, unsigned long nr_pages)
{ {
unsigned long page_limit, cur_pages, new_pages; unsigned long page_limit, cur_pages, new_pages;
@ -165,13 +170,13 @@ static void __io_rsrc_put_work(struct io_rsrc_node *ref_node)
} }
io_rsrc_node_destroy(rsrc_data->ctx, ref_node); io_rsrc_node_destroy(rsrc_data->ctx, ref_node);
if (atomic_dec_and_test(&rsrc_data->refs)) if (io_put_rsrc_data_ref(rsrc_data))
complete(&rsrc_data->done); complete(&rsrc_data->done);
} }
void io_wait_rsrc_data(struct io_rsrc_data *data) void io_wait_rsrc_data(struct io_rsrc_data *data)
{ {
if (data && !atomic_dec_and_test(&data->refs)) if (data && !io_put_rsrc_data_ref(data))
wait_for_completion(&data->done); wait_for_completion(&data->done);
} }
@ -234,7 +239,7 @@ void io_rsrc_node_switch(struct io_ring_ctx *ctx,
rsrc_node->rsrc_data = data_to_kill; rsrc_node->rsrc_data = data_to_kill;
list_add_tail(&rsrc_node->node, &ctx->rsrc_ref_list); list_add_tail(&rsrc_node->node, &ctx->rsrc_ref_list);
atomic_inc(&data_to_kill->refs); data_to_kill->refs++;
/* put master ref */ /* put master ref */
io_put_rsrc_node(ctx, rsrc_node); io_put_rsrc_node(ctx, rsrc_node);
ctx->rsrc_node = NULL; ctx->rsrc_node = NULL;
@ -267,8 +272,8 @@ __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data,
return ret; return ret;
io_rsrc_node_switch(ctx, data); io_rsrc_node_switch(ctx, data);
/* kill initial ref, already quiesced if zero */ /* kill initial ref */
if (atomic_dec_and_test(&data->refs)) if (io_put_rsrc_data_ref(data))
return 0; return 0;
data->quiesce = true; data->quiesce = true;
@ -276,17 +281,19 @@ __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data,
do { do {
ret = io_run_task_work_sig(ctx); ret = io_run_task_work_sig(ctx);
if (ret < 0) { if (ret < 0) {
atomic_inc(&data->refs);
/* wait for all works potentially completing data->done */
reinit_completion(&data->done);
mutex_lock(&ctx->uring_lock); mutex_lock(&ctx->uring_lock);
if (!data->refs) {
ret = 0;
} else {
/* restore the master reference */
data->refs++;
}
break; break;
} }
ret = wait_for_completion_interruptible(&data->done); ret = wait_for_completion_interruptible(&data->done);
if (!ret) { if (!ret) {
mutex_lock(&ctx->uring_lock); mutex_lock(&ctx->uring_lock);
if (atomic_read(&data->refs) <= 0) if (!data->refs)
break; break;
/* /*
* it has been revived by another thread while * it has been revived by another thread while
@ -361,6 +368,7 @@ __cold static int io_rsrc_data_alloc(struct io_ring_ctx *ctx,
data->nr = nr; data->nr = nr;
data->ctx = ctx; data->ctx = ctx;
data->do_put = do_put; data->do_put = do_put;
data->refs = 1;
if (utags) { if (utags) {
ret = -EFAULT; ret = -EFAULT;
for (i = 0; i < nr; i++) { for (i = 0; i < nr; i++) {
@ -371,8 +379,6 @@ __cold static int io_rsrc_data_alloc(struct io_ring_ctx *ctx,
goto fail; goto fail;
} }
} }
atomic_set(&data->refs, 1);
init_completion(&data->done); init_completion(&data->done);
*pdata = data; *pdata = data;
return 0; return 0;

2
io_uring/rsrc.h
View File

@ -33,8 +33,8 @@ struct io_rsrc_data {
u64 **tags; u64 **tags;
unsigned int nr; unsigned int nr;
rsrc_put_fn *do_put; rsrc_put_fn *do_put;
atomic_t refs;
struct completion done; struct completion done;
int refs;
bool quiesce; bool quiesce;
}; };