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Are the pages for Cache Manager mapped views shared with user mapped views?

0xrepnz0xrepnz Member Posts: 73
edited April 10 in NTFSD

I did some experiments with NtMapViewOfSection and NtWriteFile / NtReadFile and It seems like the physical page of the mapped view used by the cache manager and a mapped view mapped using NtMapViewOfSection in my process are the same. Can this situation happen? Just want to know if I get things right...
This practically means that I will see the data updated right away in NtReadFile whenever I write to the mapped view. (There is no delay waiting for the IRP_MJ_WRITE of the mapped page writer that can come seconds later)

- Ori Damari


  • rod_widdowsonrod_widdowson Member - All Emails Posts: 1,200

    Absolutely, that’s how it manages coherency. And it’s which file systems have to support the cache manager.

  • Scott_Noone_(OSR)Scott_Noone_(OSR) Administrator Posts: 3,450

    Cached I/O ends up being memory mapped I/O under the covers because the Cache Manager memory maps the file and copies data into/out of the mapping. If you then memory map the file you're seeing the same pages as the Cache Manager.


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