From: glebn@voltaire.com (Gleb Natapov)
To: Hugh Dickins <hugh@veritas.com>
Cc: "Michael S. Tsirkin" <mst@mellanox.co.il>,
Roland Dreier <roland@topspin.com>,
linux-kernel@vger.kernel.org, openib-general@openib.org
Subject: Re: [openib-general] Re: [PATCH repost] PROT_DONTCOPY: ifiniband uverbs fork support
Date: Thu, 11 Aug 2005 17:07:30 +0300 [thread overview]
Message-ID: <20050811140729.GU16361@minantech.com> (raw)
In-Reply-To: <Pine.LNX.4.61.0508111446030.10888@goblin.wat.veritas.com>
On Thu, Aug 11, 2005 at 03:04:29PM +0100, Hugh Dickins wrote:
> On Thu, 11 Aug 2005, Gleb Natapov wrote:
> > What about the idea that was floating around about new VM flag that will
> > instruct kernel to copy pages belonging to the vma on fork instead of mark
> > them as cow?
>
> It's a pretty good idea, and thanks for reminding us of it.
>
> It suffers from the general difficulty with fixes within get_user_pages,
> that we need down_write(&mm->mmap_sem) to split_vma, and even just to
> update vm_flags, whereas get_user_pages is entered with down_read.
>
Why do it form get_user_pages? Lets use madvise/mprotect interface.
Program can mrpotect(VM_COPYONFORK) address range before registering it.
--
Gleb.
next prev parent reply other threads:[~2005-08-11 14:07 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-07-19 16:55 [PATCH] fork support Michael S. Tsirkin
2005-07-25 17:19 ` [PATCH repost] PROT_DONTCOPY: ifiniband uverbs " Michael S. Tsirkin
2005-07-26 12:30 ` Hugh Dickins
2005-07-26 13:35 ` Michael S. Tsirkin
2005-08-09 18:13 ` Hugh Dickins
2005-08-10 8:30 ` Michael S. Tsirkin
2005-08-10 8:39 ` [openib-general] " Gleb Natapov
2005-08-10 13:22 ` Hugh Dickins
2005-08-10 13:26 ` Gleb Natapov
2005-08-10 15:27 ` Hugh Dickins
2005-08-11 8:02 ` Gleb Natapov
2005-08-11 14:04 ` Hugh Dickins
2005-08-11 14:07 ` Gleb Natapov [this message]
2005-08-11 14:17 ` Hugh Dickins
2005-08-11 14:11 ` Michael S. Tsirkin
2005-08-15 16:37 ` Bill Jordan
2005-08-16 7:52 ` Gleb Natapov
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