io_uring: add netmsg cache

For recvmsg/sendmsg, if they don't complete inline, we currently need
to allocate a struct io_async_msghdr for each request. This is a
somewhat large struct.

Hook up sendmsg/recvmsg to use the io_alloc_cache. This reduces the
alloc + free overhead considerably, yielding 4-5% of extra performance
running netbench.

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 bf8f953..d54b8b7 100644 (file)
--- a/include/linux/io_uring_types.h
+++ b/include/linux/io_uring_types.h
@@ -222,8 +222,7 @@ struct io_ring_ctx {
                struct io_hash_table    cancel_table_locked;
                struct list_head        cq_overflow_list;
                struct io_alloc_cache   apoll_cache;
-               struct xarray           personalities;
-               u32                     pers_next;
+               struct io_alloc_cache   netmsg_cache;
        } ____cacheline_aligned_in_smp;
 
        /* IRQ completion list, under ->completion_lock */
@@ -241,6 +240,9 @@ struct io_ring_ctx {
        unsigned int            file_alloc_start;
        unsigned int            file_alloc_end;
 
+       struct xarray           personalities;
+       u32                     pers_next;
+
        struct {
                /*
                 * We cache a range of free CQEs we can use, once exhausted it

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index c9c23e4..f697ca4 100644 (file)
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -89,6 +89,7 @@
 #include "kbuf.h"
 #include "rsrc.h"
 #include "cancel.h"
+#include "net.h"
 
 #include "timeout.h"
 #include "poll.h"
@@ -297,6 +298,7 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
        INIT_LIST_HEAD(&ctx->cq_overflow_list);
        INIT_LIST_HEAD(&ctx->io_buffers_cache);
        io_alloc_cache_init(&ctx->apoll_cache);
+       io_alloc_cache_init(&ctx->netmsg_cache);
        init_completion(&ctx->ref_comp);
        xa_init_flags(&ctx->personalities, XA_FLAGS_ALLOC1);
        mutex_init(&ctx->uring_lock);
@@ -2469,6 +2471,7 @@ static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)
                __io_cqring_overflow_flush(ctx, true);
        io_eventfd_unregister(ctx);
        io_alloc_cache_free(&ctx->apoll_cache, io_apoll_cache_free);
+       io_alloc_cache_free(&ctx->netmsg_cache, io_netmsg_cache_free);
        mutex_unlock(&ctx->uring_lock);
        io_destroy_buffers(ctx);
        if (ctx->sq_creds)

diff --git a/io_uring/net.c b/io_uring/net.c
index 6679069..1855531 100644 (file)
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -12,6 +12,7 @@
 
 #include "io_uring.h"
 #include "kbuf.h"
+#include "alloc_cache.h"
 #include "net.h"
 
 #if defined(CONFIG_NET)
@@ -97,18 +98,55 @@ static bool io_net_retry(struct socket *sock, int flags)
        return sock->type == SOCK_STREAM || sock->type == SOCK_SEQPACKET;
 }
 
+static void io_netmsg_recycle(struct io_kiocb *req, unsigned int issue_flags)
+{
+       struct io_async_msghdr *hdr = req->async_data;
+
+       if (!hdr || issue_flags & IO_URING_F_UNLOCKED)
+               return;
+
+       /* Let normal cleanup path reap it if we fail adding to the cache */
+       if (io_alloc_cache_put(&req->ctx->netmsg_cache, &hdr->cache)) {
+               req->async_data = NULL;
+               req->flags &= ~REQ_F_ASYNC_DATA;
+       }
+}
+
+static struct io_async_msghdr *io_recvmsg_alloc_async(struct io_kiocb *req,
+                                                     unsigned int issue_flags)
+{
+       struct io_ring_ctx *ctx = req->ctx;
+       struct io_cache_entry *entry;
+
+       if (!(issue_flags & IO_URING_F_UNLOCKED) &&
+           (entry = io_alloc_cache_get(&ctx->netmsg_cache)) != NULL) {
+               struct io_async_msghdr *hdr;
+
+               hdr = container_of(entry, struct io_async_msghdr, cache);
+               req->flags |= REQ_F_ASYNC_DATA;
+               req->async_data = hdr;
+               return hdr;
+       }
+
+       if (!io_alloc_async_data(req))
+               return req->async_data;
+
+       return NULL;
+}
+
 static int io_setup_async_msg(struct io_kiocb *req,
-                             struct io_async_msghdr *kmsg)
+                             struct io_async_msghdr *kmsg,
+                             unsigned int issue_flags)
 {
        struct io_async_msghdr *async_msg = req->async_data;
 
        if (async_msg)
                return -EAGAIN;
-       if (io_alloc_async_data(req)) {
+       async_msg = io_recvmsg_alloc_async(req, issue_flags);
+       if (!async_msg) {
                kfree(kmsg->free_iov);
                return -ENOMEM;
        }
-       async_msg = req->async_data;
        req->flags |= REQ_F_NEED_CLEANUP;
        memcpy(async_msg, kmsg, sizeof(*kmsg));
        async_msg->msg.msg_name = &async_msg->addr;
@@ -195,7 +233,7 @@ int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
 
        if (!(req->flags & REQ_F_POLLED) &&
            (sr->flags & IORING_RECVSEND_POLL_FIRST))
-               return io_setup_async_msg(req, kmsg);
+               return io_setup_async_msg(req, kmsg, issue_flags);
 
        flags = sr->msg_flags;
        if (issue_flags & IO_URING_F_NONBLOCK)
@@ -207,13 +245,13 @@ int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
 
        if (ret < min_ret) {
                if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK))
-                       return io_setup_async_msg(req, kmsg);
+                       return io_setup_async_msg(req, kmsg, issue_flags);
                if (ret == -ERESTARTSYS)
                        ret = -EINTR;
                if (ret > 0 && io_net_retry(sock, flags)) {
                        sr->done_io += ret;
                        req->flags |= REQ_F_PARTIAL_IO;
-                       return io_setup_async_msg(req, kmsg);
+                       return io_setup_async_msg(req, kmsg, issue_flags);
                }
                req_set_fail(req);
        }
@@ -221,6 +259,7 @@ int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags)
        if (kmsg->free_iov)
                kfree(kmsg->free_iov);
        req->flags &= ~REQ_F_NEED_CLEANUP;
+       io_netmsg_recycle(req, issue_flags);
        if (ret >= 0)
                ret += sr->done_io;
        else if (sr->done_io)
@@ -495,7 +534,7 @@ int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
 
        if (!(req->flags & REQ_F_POLLED) &&
            (sr->flags & IORING_RECVSEND_POLL_FIRST))
-               return io_setup_async_msg(req, kmsg);
+               return io_setup_async_msg(req, kmsg, issue_flags);
 
        if (io_do_buffer_select(req)) {
                void __user *buf;
@@ -519,13 +558,13 @@ int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
        ret = __sys_recvmsg_sock(sock, &kmsg->msg, sr->umsg, kmsg->uaddr, flags);
        if (ret < min_ret) {
                if (ret == -EAGAIN && force_nonblock)
-                       return io_setup_async_msg(req, kmsg);
+                       return io_setup_async_msg(req, kmsg, issue_flags);
                if (ret == -ERESTARTSYS)
                        ret = -EINTR;
                if (ret > 0 && io_net_retry(sock, flags)) {
                        sr->done_io += ret;
                        req->flags |= REQ_F_PARTIAL_IO;
-                       return io_setup_async_msg(req, kmsg);
+                       return io_setup_async_msg(req, kmsg, issue_flags);
                }
                req_set_fail(req);
        } else if ((flags & MSG_WAITALL) && (kmsg->msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) {
@@ -535,6 +574,7 @@ int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags)
        /* fast path, check for non-NULL to avoid function call */
        if (kmsg->free_iov)
                kfree(kmsg->free_iov);
+       io_netmsg_recycle(req, issue_flags);
        req->flags &= ~REQ_F_NEED_CLEANUP;
        if (ret > 0)
                ret += sr->done_io;
@@ -848,4 +888,9 @@ out:
        io_req_set_res(req, ret, 0);
        return IOU_OK;
 }
+
+void io_netmsg_cache_free(struct io_cache_entry *entry)
+{
+       kfree(container_of(entry, struct io_async_msghdr, cache));
+}
 #endif

diff --git a/io_uring/net.h b/io_uring/net.h
index 81d71d1..178a6d8 100644 (file)
--- a/io_uring/net.h
+++ b/io_uring/net.h
@@ -3,9 +3,14 @@
 #include <linux/net.h>
 #include <linux/uio.h>
 
+#include "alloc_cache.h"
+
 #if defined(CONFIG_NET)
 struct io_async_msghdr {
-       struct iovec                    fast_iov[UIO_FASTIOV];
+       union {
+               struct iovec            fast_iov[UIO_FASTIOV];
+               struct io_cache_entry   cache;
+       };
        /* points to an allocated iov, if NULL we use fast_iov instead */
        struct iovec                    *free_iov;
        struct sockaddr __user          *uaddr;
@@ -40,4 +45,10 @@ int io_socket(struct io_kiocb *req, unsigned int issue_flags);
 int io_connect_prep_async(struct io_kiocb *req);
 int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe);
 int io_connect(struct io_kiocb *req, unsigned int issue_flags);
+
+void io_netmsg_cache_free(struct io_cache_entry *entry);
+#else
+static inline void io_netmsg_cache_free(struct io_cache_entry *entry)
+{
+}
 #endif