buffer: remove list _mempool member

This broke the C++ ABI by changing the list structure size.  Also, it's
not necessary as we can infer the mempool by looking at the other list
contents.  We don't (currently) have a need to map an empty list to a
particular mempool and have that state stick.

Fixes: http://tracker.ceph.com/issues/21573
Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit 9b92d87d37e3892b0096cd728b46154aed1e2d86)

diff --git a/src/common/buffer.cc b/src/common/buffer.cc
index c518451e3581ada69e3d55b7ddbb26f241cfecbc..18ae276cc6faccaf06cf8c6128b4358bb46a5a4d 100644 (file)
--- a/src/common/buffer.cc
+++ b/src/common/buffer.cc
@@ -964,6 +964,13 @@ static std::atomic_flag buffer_debug_lock = ATOMIC_FLAG_INIT;
 
   bool buffer::ptr::at_buffer_tail() const { return _off + _len == _raw->len; }
 
+  int buffer::ptr::get_mempool() const {
+    if (_raw) {
+      return _raw->mempool;
+    }
+    return mempool::mempool_buffer_anon;
+  }
+
   void buffer::ptr::reassign_to_mempool(int pool) {
     if (_raw) {
       _raw->reassign_to_mempool(pool);
@@ -1516,7 +1523,6 @@ static std::atomic_flag buffer_debug_lock = ATOMIC_FLAG_INIT;
   {
     std::swap(_len, other._len);
     std::swap(_memcopy_count, other._memcopy_count);
-    std::swap(_mempool, other._mempool);
     _buffers.swap(other._buffers);
     append_buffer.swap(other.append_buffer);
     //last_p.swap(other.last_p);
@@ -1689,9 +1695,16 @@ static std::atomic_flag buffer_debug_lock = ATOMIC_FLAG_INIT;
     return is_aligned(CEPH_PAGE_SIZE);
   }
 
+  int buffer::list::get_mempool() const
+  {
+    if (_buffers.empty()) {
+      return mempool::mempool_buffer_anon;
+    }
+    return _buffers.back().get_mempool();
+  }
+
   void buffer::list::reassign_to_mempool(int pool)
   {
-    _mempool = pool;
     if (append_buffer.get_raw()) {
       append_buffer.get_raw()->reassign_to_mempool(pool);
     }
@@ -1702,7 +1715,6 @@ static std::atomic_flag buffer_debug_lock = ATOMIC_FLAG_INIT;
 
   void buffer::list::try_assign_to_mempool(int pool)
   {
-    _mempool = pool;
     if (append_buffer.get_raw()) {
       append_buffer.get_raw()->try_assign_to_mempool(pool);
     }
@@ -1801,10 +1813,7 @@ static std::atomic_flag buffer_debug_lock = ATOMIC_FLAG_INIT;
   void buffer::list::reserve(size_t prealloc)
   {
     if (append_buffer.unused_tail_length() < prealloc) {
-      append_buffer = buffer::create(prealloc);
-      if (_mempool >= 0) {
-       append_buffer.get_raw()->reassign_to_mempool(_mempool);
-      }
+      append_buffer = buffer::create_in_mempool(prealloc, get_mempool());
       append_buffer.set_length(0);   // unused, so far.
     }
   }
@@ -1902,11 +1911,9 @@ static std::atomic_flag buffer_debug_lock = ATOMIC_FLAG_INIT;
     unsigned gap = append_buffer.unused_tail_length();
     if (!gap) {
       // make a new append_buffer!
-      append_buffer = raw_combined::create(CEPH_BUFFER_APPEND_SIZE);
+      append_buffer = raw_combined::create(CEPH_BUFFER_APPEND_SIZE, 0,
+                                          get_mempool());
       append_buffer.set_length(0);   // unused, so far.
-      if (_mempool >= 0) {
-       append_buffer.get_raw()->reassign_to_mempool(_mempool);
-      }
     }
     append(append_buffer, append_buffer.append(c) - 1, 1);     // add segment to the list
   }
@@ -1932,11 +1939,8 @@ static std::atomic_flag buffer_debug_lock = ATOMIC_FLAG_INIT;
       size_t need = ROUND_UP_TO(len, sizeof(size_t)) + sizeof(raw_combined);
       size_t alen = ROUND_UP_TO(need, CEPH_BUFFER_ALLOC_UNIT) -
        sizeof(raw_combined);
-      append_buffer = raw_combined::create(alen, 0);
+      append_buffer = raw_combined::create(alen, 0, get_mempool());
       append_buffer.set_length(0);   // unused, so far.
-      if (_mempool >= 0) {
-       append_buffer.get_raw()->reassign_to_mempool(_mempool);
-      }
     }
   }
 

diff --git a/src/include/buffer.h b/src/include/buffer.h
index 84012665dab23385ac6eb0416a72484873558039..3fe729cf8aa84d1d69246c211717b74e3171c5c1 100644 (file)
--- a/src/include/buffer.h
+++ b/src/include/buffer.h
@@ -290,6 +290,7 @@ namespace buffer CEPH_BUFFER_API {
       return have_raw() && (start() > 0 || end() < raw_length());
     }
 
+    int get_mempool() const;
     void reassign_to_mempool(int pool);
     void try_assign_to_mempool(int pool);
 
@@ -353,7 +354,6 @@ namespace buffer CEPH_BUFFER_API {
     unsigned _len;
     unsigned _memcopy_count; //the total of memcopy using rebuild().
     ptr append_buffer;  // where i put small appends.
-    int _mempool = -1;
 
   public:
     class iterator;
@@ -687,7 +687,6 @@ namespace buffer CEPH_BUFFER_API {
       _memcopy_count = other._memcopy_count;
       last_p = begin();
       append_buffer.swap(other.append_buffer);
-      _mempool = other._mempool;
       other.clear();
       return *this;
     }
@@ -696,6 +695,7 @@ namespace buffer CEPH_BUFFER_API {
     const ptr& front() const { return _buffers.front(); }
     const ptr& back() const { return _buffers.back(); }
 
+    int get_mempool() const;
     void reassign_to_mempool(int pool);
     void try_assign_to_mempool(int pool);