1 files changed, 91 insertions, 0 deletions
diff --git a/src/mongo/util/touch_pages.cpp b/src/mongo/util/touch_pages.cpp
new file mode 100644
index 00000000000..8f4e115e5e6
--- /dev/null
+++ b/src/mongo/util/touch_pages.cpp
@@ -0,0 +1,91 @@
+/*    Copyright 2009 10gen Inc.
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+
+
+#include "pch.h"
+
+#include "mongo/util/touch_pages.h"
+
+#include <fcntl.h>
+#include <list>
+#include <string>
+
+#include "mongo/db/curop.h"
+#include "mongo/db/pdfile.h"
+#include "mongo/db/database.h"
+#include "mongo/util/mmap.h"
+#include "mongo/util/progress_meter.h"
+
+namespace mongo {
+    struct touch_location {
+        HANDLE fd;
+        int offset;
+        size_t length;
+        Extent *ext;
+    };
+        
+    void touchNs( const std::string& ns ) { 
+        std::vector< touch_location > ranges;
+        Client::ReadContext ctx(ns);
+        {
+
+            NamespaceDetails *nsd = nsdetails(ns.c_str());
+            uassert( 16154, "namespace does not exist", nsd );
+            
+            for( DiskLoc L = nsd->firstExtent; !L.isNull(); L = L.ext()->xnext )  {
+                MongoDataFile* mdf = cc().database()->getFile( L.a() );
+                massert( 16238, "can't fetch extent file structure", mdf );
+                touch_location tl;
+                tl.fd = mdf->getFd();
+                tl.offset = L.getOfs();
+                tl.ext = L.ext();
+                tl.length = tl.ext->length;
+                
+                ranges.push_back(tl);                
+            }
+
+        }
+        LockMongoFilesShared lk;
+        Lock::TempRelease tr;
+        std::string progress_msg = "touch " + ns + " extents";
+        ProgressMeterHolder pm( cc().curop()->setMessage( progress_msg.c_str() , ranges.size() ) );
+        for ( std::vector< touch_location >::iterator it = ranges.begin(); it != ranges.end(); ++it ) {
+            touch_pages( it->fd, it->offset, it->length, it->ext );
+            pm.hit();
+            killCurrentOp.checkForInterrupt(false);
+        }
+        pm.finished();
+    }
+
+#if defined(__linux__)    
+    void touch_pages( HANDLE fd, int offset, size_t length, const Extent* ext ) {
+        if ( -1 == readahead(fd, offset, length) ) {
+            massert( 16237, str::stream() << "readahead failed on fd " << fd 
+                     << " offset " << offset << " len " << length 
+                     << " : " << errnoWithDescription(errno), 0 );
+        }
+    }
+#else // if defined __linux__
+    char _touch_pages_char_reader; // goes in .bss
+    void touch_pages( HANDLE fd, int offset, size_t length, const Extent* ext ) {
+        // read first byte of every page, in order
+        const char *p = static_cast<const char *>(static_cast<const void *> (ext));
+        for( size_t i = 0; i < length; i += g_minOSPageSizeBytes ) { 
+            _touch_pages_char_reader += p[i];
+        }
+  
+    }
+#endif // if defined __linux__
+}