From: Pavel Begunkov <[email protected]>
To: [email protected]
Cc: Jens Axboe <[email protected]>,
[email protected], [email protected]
Subject: [PATCH 01/11] io_uring/rsrc: use non-pcpu refcounts for nodes
Date: Thu, 30 Mar 2023 15:53:19 +0100 [thread overview]
Message-ID: <243504691227d611f27a0f642ec8982db6ef4ead.1680187408.git.asml.silence@gmail.com> (raw)
In-Reply-To: <[email protected]>
One problem with the current rsrc infra is that often updates will
generates lots of rsrc nodes, each carry pcpu refs. That takes quite a
lot of memory, especially if there is a stall, and takes lots of CPU
cycles. Only pcpu allocations takes >50 of CPU with a naive benchmark
updating files in a loop.
Replace pcpu refs with normal refcounting. There is already a hot path
avoiding atomics / refs, but following patches will further improve it.
Signed-off-by: Pavel Begunkov <[email protected]>
---
io_uring/rsrc.c | 15 +++++----------
io_uring/rsrc.h | 6 ++++--
2 files changed, 9 insertions(+), 12 deletions(-)
diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index 7a43aed8e395..f2da9e251e3f 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -155,7 +155,7 @@ void io_rsrc_refs_refill(struct io_ring_ctx *ctx)
__must_hold(&ctx->uring_lock)
{
ctx->rsrc_cached_refs += IO_RSRC_REF_BATCH;
- percpu_ref_get_many(&ctx->rsrc_node->refs, IO_RSRC_REF_BATCH);
+ refcount_add(IO_RSRC_REF_BATCH, &ctx->rsrc_node->refs);
}
static void __io_rsrc_put_work(struct io_rsrc_node *ref_node)
@@ -220,13 +220,11 @@ void io_wait_rsrc_data(struct io_rsrc_data *data)
void io_rsrc_node_destroy(struct io_rsrc_node *ref_node)
{
- percpu_ref_exit(&ref_node->refs);
kfree(ref_node);
}
-static __cold void io_rsrc_node_ref_zero(struct percpu_ref *ref)
+__cold void io_rsrc_node_ref_zero(struct io_rsrc_node *node)
{
- struct io_rsrc_node *node = container_of(ref, struct io_rsrc_node, refs);
struct io_ring_ctx *ctx = node->rsrc_data->ctx;
unsigned long flags;
bool first_add = false;
@@ -269,11 +267,7 @@ static struct io_rsrc_node *io_rsrc_node_alloc(void)
if (!ref_node)
return NULL;
- if (percpu_ref_init(&ref_node->refs, io_rsrc_node_ref_zero,
- 0, GFP_KERNEL)) {
- kfree(ref_node);
- return NULL;
- }
+ refcount_set(&ref_node->refs, 1);
INIT_LIST_HEAD(&ref_node->node);
INIT_LIST_HEAD(&ref_node->rsrc_list);
ref_node->done = false;
@@ -298,7 +292,8 @@ void io_rsrc_node_switch(struct io_ring_ctx *ctx,
spin_unlock_irq(&ctx->rsrc_ref_lock);
atomic_inc(&data_to_kill->refs);
- percpu_ref_kill(&rsrc_node->refs);
+ /* put master ref */
+ io_rsrc_put_node(rsrc_node, 1);
ctx->rsrc_node = NULL;
}
diff --git a/io_uring/rsrc.h b/io_uring/rsrc.h
index f27f4975217d..1467b31843bc 100644
--- a/io_uring/rsrc.h
+++ b/io_uring/rsrc.h
@@ -37,7 +37,7 @@ struct io_rsrc_data {
};
struct io_rsrc_node {
- struct percpu_ref refs;
+ refcount_t refs;
struct list_head node;
struct list_head rsrc_list;
struct io_rsrc_data *rsrc_data;
@@ -54,6 +54,7 @@ struct io_mapped_ubuf {
};
void io_rsrc_put_tw(struct callback_head *cb);
+void io_rsrc_node_ref_zero(struct io_rsrc_node *node);
void io_rsrc_put_work(struct work_struct *work);
void io_rsrc_refs_refill(struct io_ring_ctx *ctx);
void io_wait_rsrc_data(struct io_rsrc_data *data);
@@ -109,7 +110,8 @@ int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg,
static inline void io_rsrc_put_node(struct io_rsrc_node *node, int nr)
{
- percpu_ref_put_many(&node->refs, nr);
+ if (refcount_sub_and_test(nr, &node->refs))
+ io_rsrc_node_ref_zero(node);
}
static inline void io_req_put_rsrc(struct io_kiocb *req)
--
2.39.1
next prev parent reply other threads:[~2023-03-30 14:54 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-30 14:53 [RFC 00/11] optimise registered buffer/file updates Pavel Begunkov
2023-03-30 14:53 ` Pavel Begunkov [this message]
2023-03-30 14:53 ` [PATCH 02/11] io_uring/rsrc: keep cached refs per node Pavel Begunkov
2023-03-30 14:53 ` [PATCH 03/11] io_uring: don't put nodes under spinlocks Pavel Begunkov
2023-03-30 14:53 ` [PATCH 04/11] io_uring: io_free_req() via tw Pavel Begunkov
2023-03-30 14:53 ` [PATCH 05/11] io_uring/rsrc: protect node refs with uring_lock Pavel Begunkov
2023-03-30 14:53 ` [PATCH 06/11] io_uring/rsrc: kill rsrc_ref_lock Pavel Begunkov
2023-03-30 14:53 ` [PATCH 07/11] io_uring/rsrc: rename rsrc_list Pavel Begunkov
2023-03-30 14:53 ` [PATCH 08/11] io_uring/rsrc: optimise io_rsrc_put allocation Pavel Begunkov
2023-03-30 14:53 ` [PATCH 09/11] io_uring/rsrc: don't offload node free Pavel Begunkov
2023-03-30 14:53 ` [PATCH 10/11] io_uring/rsrc: cache struct io_rsrc_node Pavel Begunkov
2023-03-31 14:09 ` Gabriel Krisman Bertazi
2023-03-31 16:27 ` Pavel Begunkov
2023-04-01 0:04 ` Gabriel Krisman Bertazi
2023-04-04 13:21 ` Pavel Begunkov
2023-04-04 15:48 ` Gabriel Krisman Bertazi
2023-04-04 15:52 ` Jens Axboe
2023-04-04 16:53 ` Gabriel Krisman Bertazi
2023-04-04 18:26 ` Pavel Begunkov
2023-03-30 14:53 ` [PATCH 11/11] io_uring/rsrc: add lockdep sanity checks Pavel Begunkov
2023-03-31 13:35 ` [RFC 00/11] optimise registered buffer/file updates Gabriel Krisman Bertazi
2023-03-31 16:21 ` Pavel Begunkov
2023-03-31 15:18 ` Jens Axboe
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