From: Sage Weil <sage@redhat.com>
Date: Fri, 10 Jun 2016 13:10:30 +0000 (-0400)
Subject: os/bluestore: cache: keep writing buffers out of LRU
X-Git-Tag: v11.0.0~70^2~15
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=7d9629c07e5c7f07ae78072d17608c62979f5f67;p=ceph.git

os/bluestore: cache: keep writing buffers out of LRU

Don't bother putting a writing buffer in the LRU until it is clean (and
trimmable).  Otherwise, we end up with writing items near the end of the
LRU that we have to iterate over on every trim() invocation.

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

diff --git a/src/os/bluestore/BlueStore.cc b/src/os/bluestore/BlueStore.cc
index 01a3e84637adb..c1ab8e42d2b3c 100644
--- a/src/os/bluestore/BlueStore.cc
+++ b/src/os/bluestore/BlueStore.cc
@@ -673,7 +673,9 @@ void BlueStore::BufferSpace::read(
 	res_intervals.insert(offset, l);
 	offset += l;
 	length -= l;
-	cache->_touch_buffer(b);
+	if (!b->is_writing()) {
+	  cache->_touch_buffer(b);
+	}
 	continue;
       }
       if (b->offset > offset) {
@@ -684,7 +686,9 @@ void BlueStore::BufferSpace::read(
 	offset += gap;
 	length -= gap;
       }
-      cache->_touch_buffer(b);
+      if (!b->is_writing()) {
+	cache->_touch_buffer(b);
+      }
       if (b->length > length) {
 	res[offset].substr_of(b->data, 0, length);
 	res_intervals.insert(offset, length);
@@ -714,6 +718,7 @@ void BlueStore::BufferSpace::finish_write(uint64_t seq)
       } else {
 	b->state = Buffer::STATE_CLEAN;
 	writing.erase(i++);
+	cache->_add_buffer(b, 1, nullptr);
       }
     } else {
       ++i;
diff --git a/src/os/bluestore/BlueStore.h b/src/os/bluestore/BlueStore.h
index df56d91d9e872..5d103748efaec 100644
--- a/src/os/bluestore/BlueStore.h
+++ b/src/os/bluestore/BlueStore.h
@@ -211,9 +211,10 @@ public:
     void _add_buffer(Buffer *b, int level, Buffer *near) {
       cache->_audit_lru("_add_buffer start");
       buffer_map[b->offset].reset(b);
-      cache->_add_buffer(b, level, near);
       if (b->is_writing()) {
 	writing.push_back(*b);
+      } else {
+	cache->_add_buffer(b, level, near);
       }
       cache->_audit_lru("_add_buffer end");
     }
@@ -222,9 +223,10 @@ public:
     }
     void _rm_buffer(map<uint64_t,std::unique_ptr<Buffer>>::iterator p) {
       cache->_audit_lru("_rm_buffer start");
-      cache->_rm_buffer(p->second.get());
       if (p->second->is_writing()) {
 	writing.erase(writing.iterator_to(*p->second));
+      } else {
+	cache->_rm_buffer(p->second.get());
       }
       buffer_map.erase(p);
       cache->_audit_lru("_rm_buffer end");