Merge pull request ceph#15307 from ovh/bp-64bit-mem-is-zero

inline_memory: optimized mem_is_zero for non-x64 Reviewed-by: Sage Weil <[email protected]>
stiwari · Jun 1, 2017 · 703125e · 703125e
2 parents 268d5cd + 9b5a1a4
commit 703125e
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diff --git a/src/include/inline_memory.h b/src/include/inline_memory.h
@@ -124,6 +124,15 @@ bool mem_is_zero(const char *data, size_t len)
 
 static inline bool mem_is_zero(const char *data, size_t len) {
   const char *end = data + len;
+  const char* end64 = data + (len / sizeof(uint64_t))*sizeof(uint64_t);
+
+  while (data < end64) {
+    if (*(uint64_t*)data != 0) {
+      return false;
+    }
+    data += sizeof(uint64_t);
+  }
+
   while (data < end) {
     if (*data != 0) {
       return false;

diff --git a/src/test/bufferlist.cc b/src/test/bufferlist.cc
@@ -1764,6 +1764,17 @@ TEST(BufferList, is_zero) {
     bl.append_zero(1);
     EXPECT_TRUE(bl.is_zero());
   }
+
+  for (size_t i = 1; i <= 256; ++i) {
+    bufferlist bl;
+    bl.append_zero(i);
+    EXPECT_TRUE(bl.is_zero());
+    bl.append('A');
+    // ensure buffer is a single, contiguous before testing
+    bl.rebuild();
+    EXPECT_FALSE(bl.is_zero());
+  }
+
 }
 
 TEST(BufferList, clear) {