BUG/MINOR: applet: Always release empty appctx buffers after processing

When an applet is using its own buffers, it is important to release them, if
empty, after processing to recycle unsued buffers. It is not a leak because
these buffers are necessarily released when the applet is released. But this
leads to an excess of buffer allocations.

No need to backport.

diff --git a/src/applet.c b/src/applet.c
index 984ff2661bd54b0e01637000cfe05f0cf9acb0f9..0147590416aa5330277caba2406005092e028954 100644 (file)
--- a/src/applet.c
+++ b/src/applet.c
@@ -410,6 +410,29 @@ void appctx_shut(struct appctx *appctx)
        TRACE_LEAVE(APPLET_EV_RELEASE, appctx);
 }
 
+/* releases unused buffers after processing. It will try to wake up as many
+ * entities as the number of buffers that it releases.
+ */
+static void appctx_release_buffers(struct appctx * appctx)
+{
+       int offer = 0;
+
+       if (b_size(&appctx->inbuf) && !b_data(&appctx->inbuf)) {
+               offer++;
+               b_free(&appctx->inbuf);
+       }
+       if (b_size(&appctx->outbuf) && !b_data(&appctx->outbuf)) {
+               offer++;
+               b_free(&appctx->outbuf);
+       }
+
+       /* if we're certain to have at least 1 buffer available, and there is
+        * someone waiting, we can wake up a waiter and offer them.
+        */
+       if (offer)
+               offer_buffers(appctx, offer);
+}
+
 /* Callback used to wake up an applet when a buffer is available. The applet
  * <appctx> is woken up if an input buffer was requested for the associated
  * stream connector. In this case the buffer is immediately allocated and the
@@ -866,6 +889,7 @@ struct task *task_process_applet(struct task *t, void *context, unsigned int sta
        }
 
        sc->app_ops->wake(sc);
+       appctx_release_buffers(app);
        TRACE_LEAVE(APPLET_EV_PROCESS, app);
        return t;
 }