From: Sage Weil <sage@redhat.com>
Date: Wed, 6 Jan 2016 19:19:54 +0000 (-0500)
Subject: os/fs: make aio EAGAIN backoff exponential
X-Git-Tag: v10.0.3~88^2~9
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=b0bd24843577aef2b806bc1ee2b573deeda11cb3;p=ceph.git

os/fs: make aio EAGAIN backoff exponential

Signed-off-by: Sage Weil <sage@redhat.com>
---

diff --git a/src/os/fs/FS.h b/src/os/fs/FS.h
index ec0376e4fb3..3941799398e 100644
--- a/src/os/fs/FS.h
+++ b/src/os/fs/FS.h
@@ -110,13 +110,16 @@ public:
     }
 
     int submit(aio_t &aio, int *retries) {
-      int attempts = 10;
+      // 2^16 * 125us = ~8 seconds, so max sleep is ~16 seconds
+      int attempts = 16;
+      int delay = 125;
       iocb *piocb = &aio.iocb;
       while (true) {
 	int r = io_submit(ctx, 1, &piocb);
 	if (r < 0) {
 	  if (r == -EAGAIN && attempts-- > 0) {
-	    usleep(500);
+	    usleep(delay);
+	    delay *= 2;
 	    (*retries)++;
 	    continue;
 	  }