Windows – How to flush modified memory

memorymemory managementpagefilevirtual-memorywindows

This is a follow up on my previous question, here:
Windows modified memory without a pagefile – Super User

I have no pagefile and a lot of modified memory according to resource monitor (Win 7 x64). The answerer to my original question said that the modified memory must be written to the "backing store" and when I asked if he meant files on the disk he said yes. So I have Sysinternals' RamMap program and I've tried the option 'Empty Modified Page List' but nothing changes.

Right now I'm using gigabytes of modified memory and it seems it's always that way with VMWare Workstation (several VMs open) and Firefox (ton of tabs open). How can I flush the modified memory, and is there any way to make Windows do that more often short of enabling a pagefile?

Thanks

EDIT – I've since discovered the source of several gigs of modified memory came from running Sysinternals' Process Monitor. When I closed Process Monitor I got back a few gigs. That modified memory does not show in the process list in RAMMap.

Best Answer

Windows can't write them to the disk, because they are still in use. The only way to "free" this memory is to enable a pagefile, so that the modified pages are written to the pagefile. Here they can be restored into the RAM when they are needed again.

Related Solutions

Windows modified memory without a pagefile

modified means that the memory previously belonged to a working set but was removed. However, the data were modified while it was in use and its current contents haven’t yet been written to disk or remote storage. The PTE still refers to the physical page but is marked invalid and in transition. It must be written to the backing store before the physical page can be reused.

When Firefox or VMware modified data are are in the modified list.

You should read the Windows Internals Book 6 (Chapter 10 - Memory Management) for more details.

Windows – How to find source of memory leak in Windows 7

The high memory usgae comes from a high Page table usage. To see which processes use it, install the Windows Performance Toolkit, open a command prompt as admin and run this command:

xperf -on ReferenceSet -BufferSize 1024 -MaxFile 512 -FileMode Circular  && timeout 5 && xperf -d MemUsage.etl

Open the MemUsage.etl with Windows Performance Analyzer (WPA.exe), drag and drop the graph "ResidentSet" from the left graph list to the analysis pane:

Now move the "Page Category" column to the left side and expand the "Page Table" entry:

Here you see the processes which have the high pagetable usage. On the right site (after the blue line), you see page table memory usage in MB for each process.

Related Question

Windows – How to find what is filling up the pagefile