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From: Pavel Emelyanov <xemul@parallels.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Linux MM <linux-mm@kvack.org>, Hugh Dickins <hughd@google.com>
Subject: Re: Unexpected mremap + shared anon mapping behavior
Date: Fri, 08 Mar 2013 13:04:22 +0400	[thread overview]
Message-ID: <5139A996.4070303@parallels.com> (raw)
In-Reply-To: <20130308085301.GB4411@shutemov.name>

>> So, the question is -- what should the mremap() behavior be for shared anonymous mappings?
>> Should it truncate the file to match the grown-up vma length? If yes, should it also 
>> truncate it if we mremap() the mapping to the smaller size?
> 
> I think the answer is 'no' for both cases. It's ABI change.
> 
> Should we introduce mtruncate() syscall which will truncate backing fail
> in both cases? ;)
> 

If we don't touch kernel mremap, then mtruncate can be done in glibc via /proc/pid/map_files :)

Thanks,
Pavel

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  reply	other threads:[~2013-03-08  9:04 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-08  8:27 Unexpected mremap + shared anon mapping behavior Pavel Emelyanov
2013-03-08  8:53 ` Kirill A. Shutemov
2013-03-08  9:04   ` Pavel Emelyanov [this message]
2013-03-12  2:53 ` Hugh Dickins

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