SERVER-2500 windows - eliminate mapaligned

4 files changed, 52 insertions, 6 deletions

diff --git a/db/mongommf.cpp b/db/mongommf.cpp
index 20b45247670..46724c0ff1f 100644
--- a/db/mongommf.cpp
+++ b/db/mongommf.cpp
@@ -37,6 +37,48 @@ namespace mongo {
     __declspec(noinline) void makeChunkWritable(size_t chunkno) { 

         scoped_lock lk(mapViewMutex);
 

+        if( writable.get(chunkno) ) // double check lock

+            return;

+

+        // remap all maps in this chunk.  common case is a single map, but could have more than one with smallfiles or .ns files

+        size_t chunkStart = chunkno * MemoryMappedFile::ChunkSize;

+        size_t chunkNext = chunkStart + MemoryMappedFile::ChunkSize;

+

+        scoped_lock lk2(privateViews._mutex());

+        map<void*,MongoMMF*>::iterator i = privateViews.finditer_inlock((void*) (chunkNext-1));

+        while( 1 ) {

+            const pair<void*,MongoMMF*> x = *(--i);
+            MongoMMF *mmf = x.second;
+            if( mmf == 0 )
+                break;
+
+            size_t viewStart = (size_t) x.first;
+            size_t viewEnd = viewStart + mmf->length();
+            if( viewEnd <= chunkStart )
+                break;
+
+            size_t protectStart = max(viewStart, chunkStart);
+            dassert(protectStart<chunkNext);
+
+            size_t protectEnd = min(viewEnd, chunkNext);
+            size_t protectSize = protectEnd - protectStart;

+            dassert(protectSize>0&&protectSize<=MemoryMappedFile::ChunkSize);

+

+            DWORD old;

+            bool ok = VirtualProtect((void*)protectStart, protectSize, PAGE_WRITECOPY, &old);

+            if( !ok ) {

+                DWORD e = GetLastError();

+                log() << "VirtualProtect failed " << chunkno << hex << protectStart << ' ' << protectSize << ' ' << errnoWithDescription(e) << endl;

+                assert(false);

+            }

+        }

+

+        writable.set(chunkno);

+    }

+

+    __declspec(noinline) void makeChunkWritableOld(size_t chunkno) { 

+        scoped_lock lk(mapViewMutex);
+

         if( writable.get(chunkno) )

             return;

 

@@ -118,12 +160,14 @@ namespace mongo {
     void* MemoryMappedFile::createPrivateMap() {
         assert( maphandle );
         scoped_lock lk(mapViewMutex);
-        void *p = mapaligned(maphandle, len);
+        //void *p = mapaligned(maphandle, len);
+        void *p = MapViewOfFile(maphandle, FILE_MAP_READ, 0, 0, 0);
         if ( p == 0 ) {
             DWORD e = GetLastError();
             log() << "createPrivateMap failed " << filename() << " " << errnoWithDescription(e) << endl;
         }
         else {
+            clearWritableBits(p);
             views.push_back(p);
         }
         return p;
@@ -135,7 +179,7 @@ namespace mongo {
 
         scoped_lock lk(mapViewMutex);
 
-        unmapped(oldPrivateAddr);
+        clearWritableBits(oldPrivateAddr);
 
         if( !UnmapViewOfFile(oldPrivateAddr) ) {
             DWORD e = GetLastError();
diff --git a/db/mongommf.h b/db/mongommf.h
index f7716735cd9..7061903512f 100644
--- a/db/mongommf.h
+++ b/db/mongommf.h
@@ -128,6 +128,8 @@ namespace mongo {
         mutex& _mutex() { return _m; }
         MongoMMF* find_inlock(void *p, /*out*/ size_t& ofs);
 
+        map<void*,MongoMMF*>::iterator PointerToMMF::finditer_inlock(void *p) { return _views.upper_bound(p); }
+
     private:
         mutex _m;
         map<void*, MongoMMF*> _views;
diff --git a/util/mmap.h b/util/mmap.h
index 28e7be7c5fe..2ef417690c4 100644
--- a/util/mmap.h
+++ b/util/mmap.h
@@ -190,12 +190,12 @@ namespace mongo {
 
 #ifdef _WIN32
         boost::shared_ptr<mutex> _flushMutex;
-        void unmapped(void *privateView);
+        void clearWritableBits(void *privateView);
     public:
         static const unsigned ChunkSize = 64 * 1024 * 1024;
         static const unsigned NChunks = 1024 * 1024;
 #else
-        void unmapped(void *privateView) { }
+        void clearWritableBits(void *privateView) { }
 #endif
 
     protected:
diff --git a/util/mmap_win.cpp b/util/mmap_win.cpp
index 76837edd5c4..0b0b834becd 100644
--- a/util/mmap_win.cpp
+++ b/util/mmap_win.cpp
@@ -28,7 +28,7 @@ namespace mongo {
     ourbitset writable;
 
     /** notification on unmapping so we can clear writable bits */
-    void MemoryMappedFile::unmapped(void *p) {
+    void MemoryMappedFile::clearWritableBits(void *p) {
         for( unsigned i = ((size_t)p)/ChunkSize; i <= (((size_t)p)+len)/ChunkSize; i++ ) {
             writable.clear(i);
             assert( !writable.get(i) );
@@ -45,7 +45,7 @@ namespace mongo {
 
     void MemoryMappedFile::close() {
         for( vector<void*>::iterator i = views.begin(); i != views.end(); i++ ) {
-            unmapped(*i);
+            clearWritableBits(*i);
             UnmapViewOfFile(*i);
         }
         views.clear();