Merge tag 'pull-loongarch-20240201' of https://gitlab.com/gaosong/qemu into staging

[mirror_qemu.git] / util / aio-posix.c

diff --git a/util/aio-posix.c b/util/aio-posix.c
index be0182a3c64f7e2413a925d91f88902820e4fbc7..266c9dd35fa04c91fc65345a45bd56e6fd9a78d7 100644 (file)
--- a/util/aio-posix.c
+++ b/util/aio-posix.c
@@ -15,6 +15,7 @@
 
 #include "qemu/osdep.h"
 #include "block/block.h"
+#include "block/thread-pool.h"
 #include "qemu/main-loop.h"
 #include "qemu/rcu.h"
 #include "qemu/rcu_queue.h"
@@ -98,7 +99,6 @@ static bool aio_remove_fd_handler(AioContext *ctx, AioHandler *node)
 
 void aio_set_fd_handler(AioContext *ctx,
                         int fd,
-                        bool is_external,
                         IOHandler *io_read,
                         IOHandler *io_write,
                         AioPollFn *io_poll,
@@ -143,7 +143,6 @@ void aio_set_fd_handler(AioContext *ctx,
         new_node->io_poll = io_poll;
         new_node->io_poll_ready = io_poll_ready;
         new_node->opaque = opaque;
-        new_node->is_external = is_external;
 
         if (is_new) {
             new_node->pfd.fd = fd;
@@ -179,9 +178,9 @@ void aio_set_fd_handler(AioContext *ctx,
     }
 }
 
-void aio_set_fd_poll(AioContext *ctx, int fd,
-                     IOHandler *io_poll_begin,
-                     IOHandler *io_poll_end)
+static void aio_set_fd_poll(AioContext *ctx, int fd,
+                            IOHandler *io_poll_begin,
+                            IOHandler *io_poll_end)
 {
     AioHandler *node = find_aio_handler(ctx, fd);
 
@@ -195,12 +194,11 @@ void aio_set_fd_poll(AioContext *ctx, int fd,
 
 void aio_set_event_notifier(AioContext *ctx,
                             EventNotifier *notifier,
-                            bool is_external,
                             EventNotifierHandler *io_read,
                             AioPollFn *io_poll,
                             EventNotifierHandler *io_poll_ready)
 {
-    aio_set_fd_handler(ctx, event_notifier_get_fd(notifier), is_external,
+    aio_set_fd_handler(ctx, event_notifier_get_fd(notifier),
                        (IOHandler *)io_read, NULL, io_poll,
                        (IOHandler *)io_poll_ready, notifier);
 }
@@ -284,13 +282,11 @@ bool aio_pending(AioContext *ctx)
 
         /* TODO should this check poll ready? */
         revents = node->pfd.revents & node->pfd.events;
-        if (revents & (G_IO_IN | G_IO_HUP | G_IO_ERR) && node->io_read &&
-            aio_node_check(ctx, node->is_external)) {
+        if (revents & (G_IO_IN | G_IO_HUP | G_IO_ERR) && node->io_read) {
             result = true;
             break;
         }
-        if (revents & (G_IO_OUT | G_IO_ERR) && node->io_write &&
-            aio_node_check(ctx, node->is_external)) {
+        if (revents & (G_IO_OUT | G_IO_ERR) && node->io_write) {
             result = true;
             break;
         }
@@ -349,11 +345,20 @@ static bool aio_dispatch_handler(AioContext *ctx, AioHandler *node)
         QLIST_INSERT_HEAD(&ctx->poll_aio_handlers, node, node_poll);
     }
     if (!QLIST_IS_INSERTED(node, node_deleted) &&
-        poll_ready && revents == 0 &&
-        aio_node_check(ctx, node->is_external) &&
-        node->io_poll_ready) {
+        poll_ready && revents == 0 && node->io_poll_ready) {
+        /*
+         * Remove temporarily to avoid infinite loops when ->io_poll_ready()
+         * calls aio_poll() before clearing the condition that made the poll
+         * handler become ready.
+         */
+        QLIST_SAFE_REMOVE(node, node_poll);
+
         node->io_poll_ready(node->opaque);
 
+        if (!QLIST_IS_INSERTED(node, node_poll)) {
+            QLIST_INSERT_HEAD(&ctx->poll_aio_handlers, node, node_poll);
+        }
+
         /*
          * Return early since revents was zero. aio_notify() does not count as
          * progress.
@@ -363,7 +368,6 @@ static bool aio_dispatch_handler(AioContext *ctx, AioHandler *node)
 
     if (!QLIST_IS_INSERTED(node, node_deleted) &&
         (revents & (G_IO_IN | G_IO_HUP | G_IO_ERR)) &&
-        aio_node_check(ctx, node->is_external) &&
         node->io_read) {
         node->io_read(node->opaque);
 
@@ -374,7 +378,6 @@ static bool aio_dispatch_handler(AioContext *ctx, AioHandler *node)
     }
     if (!QLIST_IS_INSERTED(node, node_deleted) &&
         (revents & (G_IO_OUT | G_IO_ERR)) &&
-        aio_node_check(ctx, node->is_external) &&
         node->io_write) {
         node->io_write(node->opaque);
         progress = true;
@@ -435,8 +438,7 @@ static bool run_poll_handlers_once(AioContext *ctx,
     AioHandler *tmp;
 
     QLIST_FOREACH_SAFE(node, &ctx->poll_aio_handlers, node_poll, tmp) {
-        if (aio_node_check(ctx, node->is_external) &&
-            node->io_poll(node->opaque)) {
+        if (node->io_poll(node->opaque)) {
             aio_add_poll_ready_handler(ready_list, node);
 
             node->poll_idle_timeout = now + POLL_IDLE_INTERVAL_NS;
@@ -584,18 +586,16 @@ static bool try_poll_mode(AioContext *ctx, AioHandlerList *ready_list,
 
     max_ns = qemu_soonest_timeout(*timeout, ctx->poll_ns);
     if (max_ns && !ctx->fdmon_ops->need_wait(ctx)) {
+        /*
+         * Enable poll mode. It pairs with the poll_set_started() in
+         * aio_poll() which disables poll mode.
+         */
         poll_set_started(ctx, ready_list, true);
 
         if (run_poll_handlers(ctx, ready_list, max_ns, timeout)) {
             return true;
         }
     }
-
-    if (poll_set_started(ctx, ready_list, false)) {
-        *timeout = 0;
-        return true;
-    }
-
     return false;
 }
 
@@ -656,6 +656,17 @@ bool aio_poll(AioContext *ctx, bool blocking)
      * system call---a single round of run_poll_handlers_once suffices.
      */
     if (timeout || ctx->fdmon_ops->need_wait(ctx)) {
+        /*
+         * Disable poll mode. poll mode should be disabled before the call
+         * of ctx->fdmon_ops->wait() so that guest's notification can wake
+         * up IO threads when some work becomes pending. It is essential to
+         * avoid hangs or unnecessary latency.
+         */
+        if (poll_set_started(ctx, &ready_list, false)) {
+            timeout = 0;
+            progress = true;
+        }
+
         ctx->fdmon_ops->wait(ctx, &ready_list, timeout);
     }
 
@@ -766,8 +777,7 @@ void aio_context_set_poll_params(AioContext *ctx, int64_t max_ns,
     aio_notify(ctx);
 }
 
-void aio_context_set_aio_params(AioContext *ctx, int64_t max_batch,
-                                Error **errp)
+void aio_context_set_aio_params(AioContext *ctx, int64_t max_batch)
 {
     /*
      * No thread synchronization here, it doesn't matter if an incorrect value