[RFC] msgr: Prevent unbounded use of bufferlist memory by throttling incoming messages.

Commit Message

Jim Schutt June 3, 2010, 9:25 p.m. UTC

None

Patch

diff --git a/src/msg/SimpleMessenger.cc b/src/msg/SimpleMessenger.cc
index a7fb18d..11163e3 100644
--- a/src/msg/SimpleMessenger.cc
+++ b/src/msg/SimpleMessenger.cc
@@ -1750,6 +1750,20 @@  Message *SimpleMessenger::Pipe::read_message()
   unsigned data_off = le32_to_cpu(header.data_off);
   if (data_len) {
     int left = data_len;
+    int throttled = 0;
+
+    while (buffer_total_alloc.read() + data_len > (64*1024*1024)) {
+      struct timespec sleepy_time = {0, (1000 * 1000)}; // 1 msec
+      if (!throttled)
+	dout(4) << " pipe reader paused" << "; buffer_total_alloc "
+		<< buffer_total_alloc.read() << dendl;
+      ::nanosleep(&sleepy_time, 0);
+      throttled++;
+    }
+    if (throttled)
+      dout(4) << " pipe reader unpaused; buffer_total_alloc "
+	       << buffer_total_alloc.read() << dendl;
+      
     if (data_off & ~PAGE_MASK) {
       // head
       int head = MIN(PAGE_SIZE - (data_off & ~PAGE_MASK),