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From:   Pavel Begunkov <asml.silence@gmail.com>
To:     io-uring@vger.kernel.org
Cc:     Jens Axboe <axboe@kernel.dk>, asml.silence@gmail.com,
        linux-kernel@vger.kernel.org
Subject: [PATCH v2 10/13] io_uring/rsrc: cache struct io_rsrc_node
Date:   Tue,  4 Apr 2023 13:39:54 +0100
Message-Id: <252a9d9ef9654e6467af30fdc02f57c0118fb76e.1680576071.git.asml.silence@gmail.com>
In-Reply-To: <cover.1680576071.git.asml.silence@gmail.com>
References: <cover.1680576071.git.asml.silence@gmail.com>
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Add allocation cache for struct io_rsrc_node, it's always allocated and
put under ->uring_lock, so it doesn't need any extra synchronisation
around caches.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 include/linux/io_uring_types.h |  1 +
 io_uring/io_uring.c            | 11 +++++++++--
 io_uring/rsrc.c                | 23 +++++++++++++++--------
 io_uring/rsrc.h                |  9 +++++++--
 4 files changed, 32 insertions(+), 12 deletions(-)

diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h
index 47496059e13a..5d772e36e7fc 100644
--- a/include/linux/io_uring_types.h
+++ b/include/linux/io_uring_types.h
@@ -332,6 +332,7 @@ struct io_ring_ctx {
 
 	/* protected by ->uring_lock */
 	struct list_head		rsrc_ref_list;
+	struct io_alloc_cache		rsrc_node_cache;
 
 	struct list_head		io_buffers_pages;
 
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index d6a0025afc31..419d6f42935f 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -310,6 +310,7 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
 	INIT_LIST_HEAD(&ctx->sqd_list);
 	INIT_LIST_HEAD(&ctx->cq_overflow_list);
 	INIT_LIST_HEAD(&ctx->io_buffers_cache);
+	io_alloc_cache_init(&ctx->rsrc_node_cache, sizeof(struct io_rsrc_node));
 	io_alloc_cache_init(&ctx->apoll_cache, sizeof(struct async_poll));
 	io_alloc_cache_init(&ctx->netmsg_cache, sizeof(struct io_async_msghdr));
 	init_completion(&ctx->ref_comp);
@@ -2790,6 +2791,11 @@ static void io_req_caches_free(struct io_ring_ctx *ctx)
 	mutex_unlock(&ctx->uring_lock);
 }
 
+static void io_rsrc_node_cache_free(struct io_cache_entry *entry)
+{
+	kfree(container_of(entry, struct io_rsrc_node, cache));
+}
+
 static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)
 {
 	io_sq_thread_finish(ctx);
@@ -2815,9 +2821,9 @@ static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)
 
 	/* there are no registered resources left, nobody uses it */
 	if (ctx->rsrc_node)
-		io_rsrc_node_destroy(ctx->rsrc_node);
+		io_rsrc_node_destroy(ctx, ctx->rsrc_node);
 	if (ctx->rsrc_backup_node)
-		io_rsrc_node_destroy(ctx->rsrc_backup_node);
+		io_rsrc_node_destroy(ctx, ctx->rsrc_backup_node);
 
 	WARN_ON_ONCE(!list_empty(&ctx->rsrc_ref_list));
 
@@ -2829,6 +2835,7 @@ static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)
 #endif
 	WARN_ON_ONCE(!list_empty(&ctx->ltimeout_list));
 
+	io_alloc_cache_free(&ctx->rsrc_node_cache, io_rsrc_node_cache_free);
 	if (ctx->mm_account) {
 		mmdrop(ctx->mm_account);
 		ctx->mm_account = NULL;
diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index 77cb2f8cfd68..cbf563fcb053 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -164,7 +164,7 @@ static void __io_rsrc_put_work(struct io_rsrc_node *ref_node)
 		kfree(prsrc);
 	}
 
-	io_rsrc_node_destroy(ref_node);
+	io_rsrc_node_destroy(rsrc_data->ctx, ref_node);
 	if (atomic_dec_and_test(&rsrc_data->refs))
 		complete(&rsrc_data->done);
 }
@@ -175,9 +175,10 @@ void io_wait_rsrc_data(struct io_rsrc_data *data)
 		wait_for_completion(&data->done);
 }
 
-void io_rsrc_node_destroy(struct io_rsrc_node *ref_node)
+void io_rsrc_node_destroy(struct io_ring_ctx *ctx, struct io_rsrc_node *node)
 {
-	kfree(ref_node);
+	if (!io_alloc_cache_put(&ctx->rsrc_node_cache, &node->cache))
+		kfree(node);
 }
 
 void io_rsrc_node_ref_zero(struct io_rsrc_node *node)
@@ -198,13 +199,19 @@ void io_rsrc_node_ref_zero(struct io_rsrc_node *node)
 	}
 }
 
-static struct io_rsrc_node *io_rsrc_node_alloc(void)
+static struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx)
 {
 	struct io_rsrc_node *ref_node;
+	struct io_cache_entry *entry;
 
-	ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL);
-	if (!ref_node)
-		return NULL;
+	entry = io_alloc_cache_get(&ctx->rsrc_node_cache);
+	if (entry) {
+		ref_node = container_of(entry, struct io_rsrc_node, cache);
+	} else {
+		ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL);
+		if (!ref_node)
+			return NULL;
+	}
 
 	ref_node->refs = 1;
 	INIT_LIST_HEAD(&ref_node->node);
@@ -243,7 +250,7 @@ int io_rsrc_node_switch_start(struct io_ring_ctx *ctx)
 {
 	if (ctx->rsrc_backup_node)
 		return 0;
-	ctx->rsrc_backup_node = io_rsrc_node_alloc();
+	ctx->rsrc_backup_node = io_rsrc_node_alloc(ctx);
 	return ctx->rsrc_backup_node ? 0 : -ENOMEM;
 }
 
diff --git a/io_uring/rsrc.h b/io_uring/rsrc.h
index 11703082d125..3b9f4c57c47c 100644
--- a/io_uring/rsrc.h
+++ b/io_uring/rsrc.h
@@ -4,6 +4,8 @@
 
 #include <net/af_unix.h>
 
+#include "alloc_cache.h"
+
 #define IO_RSRC_TAG_TABLE_SHIFT	(PAGE_SHIFT - 3)
 #define IO_RSRC_TAG_TABLE_MAX	(1U << IO_RSRC_TAG_TABLE_SHIFT)
 #define IO_RSRC_TAG_TABLE_MASK	(IO_RSRC_TAG_TABLE_MAX - 1)
@@ -37,8 +39,11 @@ struct io_rsrc_data {
 };
 
 struct io_rsrc_node {
+	union {
+		struct io_cache_entry		cache;
+		struct io_rsrc_data		*rsrc_data;
+	};
 	struct list_head		node;
-	struct io_rsrc_data		*rsrc_data;
 	struct llist_node		llist;
 	int				refs;
 	bool				done;
@@ -65,7 +70,7 @@ 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_wait_rsrc_data(struct io_rsrc_data *data);
-void io_rsrc_node_destroy(struct io_rsrc_node *ref_node);
+void io_rsrc_node_destroy(struct io_ring_ctx *ctx, struct io_rsrc_node *ref_node);
 int io_rsrc_node_switch_start(struct io_ring_ctx *ctx);
 int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx,
 			  struct io_rsrc_node *node, void *rsrc);
-- 
2.39.1