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Message-ID: <63af3bba-c824-4b2c-a670-6329eeb232aa@samba.org>
Date: Mon, 11 Nov 2024 13:55:38 +0100
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Subject: Re: [PATCHSET v4] Uncached buffered IO
To: Jens Axboe <axboe@kernel.dk>, linux-mm@kvack.org,
 linux-fsdevel@vger.kernel.org
Cc: hannes@cmpxchg.org, clm@meta.com, linux-kernel@vger.kernel.org
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From: Stefan Metzmacher <metze@samba.org>
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Hi Jens,

I'm wondering about the impact on memory mapped files.

Let's say one (or more) process(es) called mmap on a file in order to
use the content of the file as persistent shared memory.
As far as I understand pages from the page cache are used for this.

Now another process uses RWF_UNCACHED for a read of the same file.
What happens if the pages are removed from the page cache?
Or is the removal deferred based on some refcount?

Thanks!
metze