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From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>,
	Mark Williamson <mwilliamson@undo-software.com>,
	Mark Seaborn <mseaborn@chromium.org>,
	kernel list <linux-kernel@vger.kernel.org>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Pavel Emelyanov <xemul@parallels.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andy Lutomirski <luto@amacapital.net>,
	Linux API <linux-api@vger.kernel.org>,
	Finn Grimwood <fgrimwood@undo-software.com>,
	Daniel James <djames@undo-software.com>,
	Cyrill Gorcunov <gorcunov@openvz.org>
Subject: Re: Regression: Requiring CAP_SYS_ADMIN for /proc/<pid>/pagemap causes application-level breakage
Date: Thu, 30 Apr 2015 00:37:44 +0300	[thread overview]
Message-ID: <20150429213744.GA12552@node.dhcp.inet.fi> (raw)
In-Reply-To: <CA+55aFw-dK4U3Z_gi5wEdGsPz0ZaQMizETKqS-=ajpDAu03Fnw@mail.gmail.com>

On Wed, Apr 29, 2015 at 02:18:49PM -0700, Linus Torvalds wrote:
> On Wed, Apr 29, 2015 at 2:05 PM, Kirill A. Shutemov
> <kirill@shutemov.name> wrote:
> >
> > This sounds too ugly to be exposed it as ABI.
> 
> Oh, pretty it ain't. However, regressions in many ways are worse. If
> it makes it possible to not regress...

One idea is to extend kcmp(2) with KCMP_PAGE. idx1 and idx2 are virtual
addresses in two processes. It returns 0 if addresses points to the same
page and 3 otherwise.

Would it be enough for the use case?

I guess it could be too slow to check one page a time...

Invent new kcmpv(2)? ;)

-- 
 Kirill A. Shutemov

  reply	other threads:[~2015-04-29 21:39 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-24 15:01 Regression: Requiring CAP_SYS_ADMIN for /proc/<pid>/pagemap causes application-level breakage Mark Williamson
2015-04-24 15:26 ` Mark Seaborn
2015-04-24 16:43   ` Mark Williamson
2015-04-29 18:44     ` Mark Williamson
2015-04-29 19:23       ` Mark Williamson
2015-04-29 19:36       ` Kirill A. Shutemov
2015-04-29 20:24         ` Mark Williamson
2015-04-29 20:33         ` Linus Torvalds
2015-04-29 20:44           ` Konstantin Khlebnikov
2015-04-29 21:02             ` Linus Torvalds
2015-04-29 21:05               ` Kirill A. Shutemov
2015-04-29 21:18                 ` Linus Torvalds
2015-04-29 21:37                   ` Kirill A. Shutemov [this message]
2015-04-30 11:43               ` Konstantin Khlebnikov
2015-04-30 13:11                 ` Konstantin Khlebnikov
2015-04-30 13:22                   ` Kirill A. Shutemov
2015-04-30 13:32                     ` Konstantin Khlebnikov
2015-04-30 18:45                     ` Mark Williamson
2015-04-30 18:32                   ` Mark Williamson
2015-04-30 11:50               ` Mark Williamson
     [not found] <CAEVpBa+7Yp+zCTczZqBd6Qp_uM7yy0i8YZfZkUbDeUsPpKtqRQ@mail.gmail.com>
2015-04-24 16:08 ` Linus Torvalds
2015-04-24 16:10   ` Andy Lutomirski
2015-04-24 16:27     ` Linus Torvalds
2015-04-29 14:38     ` Mark Williamson
2015-04-24 16:46   ` Mark Williamson

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