io_uring/rsrc: keep cached refs per node

We cache refs of the current node (i.e. ctx->rsrc_node) in
ctx->rsrc_cached_refs. We'll be moving away from atomics, so move the
cached refs in struct io_rsrc_node for now. It's a prep patch and
shouldn't change anything in practise.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/9edc3669c1d71b06c2dca78b2b2b8bb9292738b9.1680576071.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h
index 561fa42..a0a5b59 100644 (file)
--- a/include/linux/io_uring_types.h
+++ b/include/linux/io_uring_types.h
@@ -240,7 +240,6 @@ struct io_ring_ctx {
                 * uring_lock, and updated through io_uring_register(2)
                 */
                struct io_rsrc_node     *rsrc_node;
-               int                     rsrc_cached_refs;
                atomic_t                cancel_seq;
                struct io_file_table    file_table;
                unsigned                nr_user_files;

diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index f2da9e2..1e7c960 100644 (file)
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -36,9 +36,11 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
 void io_rsrc_refs_drop(struct io_ring_ctx *ctx)
        __must_hold(&ctx->uring_lock)
 {
-       if (ctx->rsrc_cached_refs) {
-               io_rsrc_put_node(ctx->rsrc_node, ctx->rsrc_cached_refs);
-               ctx->rsrc_cached_refs = 0;
+       struct io_rsrc_node *node = ctx->rsrc_node;
+
+       if (node && node->cached_refs) {
+               io_rsrc_put_node(node, node->cached_refs);
+               node->cached_refs = 0;
        }
 }
 
@@ -151,11 +153,11 @@ static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slo
        *slot = NULL;
 }
 
-void io_rsrc_refs_refill(struct io_ring_ctx *ctx)
+void io_rsrc_refs_refill(struct io_ring_ctx *ctx, struct io_rsrc_node *node)
        __must_hold(&ctx->uring_lock)
 {
-       ctx->rsrc_cached_refs += IO_RSRC_REF_BATCH;
-       refcount_add(IO_RSRC_REF_BATCH, &ctx->rsrc_node->refs);
+       node->cached_refs += IO_RSRC_REF_BATCH;
+       refcount_add(IO_RSRC_REF_BATCH, &node->refs);
 }
 
 static void __io_rsrc_put_work(struct io_rsrc_node *ref_node)
@@ -300,6 +302,7 @@ void io_rsrc_node_switch(struct io_ring_ctx *ctx,
        if (!ctx->rsrc_node) {
                ctx->rsrc_node = ctx->rsrc_backup_node;
                ctx->rsrc_backup_node = NULL;
+               ctx->rsrc_node->cached_refs = 0;
        }
 }
 

diff --git a/io_uring/rsrc.h b/io_uring/rsrc.h
index 1467b31..950535e 100644 (file)
--- a/io_uring/rsrc.h
+++ b/io_uring/rsrc.h
@@ -43,6 +43,7 @@ struct io_rsrc_node {
        struct io_rsrc_data             *rsrc_data;
        struct llist_node               llist;
        bool                            done;
+       int                             cached_refs;
 };
 
 struct io_mapped_ubuf {
@@ -56,7 +57,7 @@ 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_rsrc_refs_refill(struct io_ring_ctx *ctx, struct io_rsrc_node *node);
 void io_wait_rsrc_data(struct io_rsrc_data *data);
 void io_rsrc_node_destroy(struct io_rsrc_node *ref_node);
 void io_rsrc_refs_drop(struct io_ring_ctx *ctx);
@@ -128,17 +129,18 @@ static inline void io_req_put_rsrc_locked(struct io_kiocb *req,
 
        if (node) {
                if (node == ctx->rsrc_node)
-                       ctx->rsrc_cached_refs++;
+                       node->cached_refs++;
                else
                        io_rsrc_put_node(node, 1);
        }
 }
 
-static inline void io_charge_rsrc_node(struct io_ring_ctx *ctx)
+static inline void io_charge_rsrc_node(struct io_ring_ctx *ctx,
+                                      struct io_rsrc_node *node)
 {
-       ctx->rsrc_cached_refs--;
-       if (unlikely(ctx->rsrc_cached_refs < 0))
-               io_rsrc_refs_refill(ctx);
+       node->cached_refs--;
+       if (unlikely(node->cached_refs < 0))
+               io_rsrc_refs_refill(ctx, node);
 }
 
 static inline void io_req_set_rsrc_node(struct io_kiocb *req,
@@ -151,7 +153,7 @@ static inline void io_req_set_rsrc_node(struct io_kiocb *req,
                lockdep_assert_held(&ctx->uring_lock);
 
                req->rsrc_node = ctx->rsrc_node;
-               io_charge_rsrc_node(ctx);
+               io_charge_rsrc_node(ctx, ctx->rsrc_node);
                io_ring_submit_unlock(ctx, issue_flags);
        }
 }