From 757ef4682b6aa29fdf752ad47f0d63eb48b261cf Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Tue, 4 Apr 2023 13:39:56 +0100 Subject: [PATCH] io_uring/rsrc: optimise io_rsrc_data refcounting 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 Link: https://lore.kernel.org/r/e73c3d6820cf679532696d790b5b8fae23537213.1680576071.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- io_uring/rsrc.c | 30 ++++++++++++++++++------------ io_uring/rsrc.h | 2 +- 2 files changed, 19 insertions(+), 13 deletions(-) diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c index d4bca5e..603a783 100644 --- a/io_uring/rsrc.c +++ b/io_uring/rsrc.c @@ -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_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) { 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); - if (atomic_dec_and_test(&rsrc_data->refs)) + if (io_put_rsrc_data_ref(rsrc_data)) complete(&rsrc_data->done); } 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); } @@ -234,7 +239,7 @@ void io_rsrc_node_switch(struct io_ring_ctx *ctx, rsrc_node->rsrc_data = data_to_kill; list_add_tail(&rsrc_node->node, &ctx->rsrc_ref_list); - atomic_inc(&data_to_kill->refs); + data_to_kill->refs++; /* put master ref */ io_put_rsrc_node(ctx, rsrc_node); ctx->rsrc_node = NULL; @@ -267,8 +272,8 @@ __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data, return ret; io_rsrc_node_switch(ctx, data); - /* kill initial ref, already quiesced if zero */ - if (atomic_dec_and_test(&data->refs)) + /* kill initial ref */ + if (io_put_rsrc_data_ref(data)) return 0; data->quiesce = true; @@ -276,17 +281,19 @@ __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data, do { ret = io_run_task_work_sig(ctx); if (ret < 0) { - atomic_inc(&data->refs); - /* wait for all works potentially completing data->done */ - reinit_completion(&data->done); mutex_lock(&ctx->uring_lock); + if (!data->refs) { + ret = 0; + } else { + /* restore the master reference */ + data->refs++; + } break; } - ret = wait_for_completion_interruptible(&data->done); if (!ret) { mutex_lock(&ctx->uring_lock); - if (atomic_read(&data->refs) <= 0) + if (!data->refs) break; /* * 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->ctx = ctx; data->do_put = do_put; + data->refs = 1; if (utags) { ret = -EFAULT; for (i = 0; i < nr; i++) { @@ -371,8 +379,6 @@ __cold static int io_rsrc_data_alloc(struct io_ring_ctx *ctx, goto fail; } } - - atomic_set(&data->refs, 1); init_completion(&data->done); *pdata = data; return 0; diff --git a/io_uring/rsrc.h b/io_uring/rsrc.h index cf24c3f..7ab9b2b 100644 --- a/io_uring/rsrc.h +++ b/io_uring/rsrc.h @@ -33,8 +33,8 @@ struct io_rsrc_data { u64 **tags; unsigned int nr; rsrc_put_fn *do_put; - atomic_t refs; struct completion done; + int refs; bool quiesce; }; -- 2.7.4