Re: [Linux-cachefs] Re: Data Redundancy

[David Howells <dhowells redhat com>]

gaurav <gaurav1207 gmail com> wrote:

> can u please clarify the following points with reasons
> it is said that the kernel can access any pagecache within the system
> without any permission.

There is only the *one* pagecache in each system.  That's where the kernel
caches the data it has read from various files.

The kernel can read or write any page in the pagecache that it likes.

mmap() gives a user process a window onto a part of the pagecache.

> but here the question arises that if the kernel is accessing any pagecache
> which is present in any user address space, does a new pagecache get created
> by the kernel or the same pagecache is used by it?

There is only one pagecache per system.

David