From: Cary Coutant <ccoutant@gmail.com>
To: James Y Knight <jyknight@google.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>, gnu-gabi@sourceware.org
Subject: Re: gABI extension proposal: PT_SHMMAP
Date: Sun, 01 Jan 2017 00:00:00 -0000 [thread overview]
Message-ID: <CAJimCsFaVCo48abjrZUTOyuyfzfzQatQgaXp2fzE5msjtXA+RA@mail.gmail.com> (raw)
In-Reply-To: <CAA2zVHqBowJEUjSNQw_867_79_FsSKJLLxf9GQQA+r+fGPToUQ@mail.gmail.com>
> Why is MAP_SHARED even needed for the linux vdso use-case?
>
> All the mappings created for the vdso are read-only mappings, right?
> And on Linux, MAP_PRIVATE mappings already reflect changes made to the
> underlying file, so long as the process hasn't written to the page, I
> think?
>
> So, if you're intending to use this to implement the "vvar" mapping,
> isn't the default MAP_PRIVATE already sufficient?
He mentioned that this was for the kernel-provided *data* page,
implying to me that he wants a writable, but still sharable (i.e., not
copy-on-write) mapping.
It seems generally useful to me. I probably wouldn't object to a new
gABI bit, but a little more background would be helpful in deciding.
-cary
next prev parent reply other threads:[~2017-06-08 0:30 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-01 0:00 H. Peter Anvin
2017-01-01 0:00 ` James Y Knight via gnu-gabi
2017-01-01 0:00 ` Cary Coutant [this message]
2017-01-01 0:00 ` H. Peter Anvin
2017-01-01 0:00 ` Suprateeka R Hegde
2017-01-01 0:00 ` H. Peter Anvin
2017-01-01 0:00 ` Suprateeka R Hegde
2017-01-01 0:00 ` Cary Coutant
2017-01-01 0:00 ` hpa
2017-01-01 0:00 ` Suprateeka R Hegde
2017-01-01 0:00 ` H. Peter Anvin
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