Date: Thu, 28 Feb 2008 17:03:01 -0800 (PST)
From: Christoph Lameter <clameter@sgi.com>
To: Andrea Arcangeli <andrea@qumranet.com>
cc: Jack Steiner <steiner@sgi.com>, Nick Piggin <npiggin@suse.de>,
       akpm@linux-foundation.org, Robin Holt <holt@sgi.com>,
       Avi Kivity <avi@qumranet.com>, Izik Eidus <izike@qumranet.com>,
       kvm-devel@lists.sourceforge.net,
       Peter Zijlstra <a.p.zijlstra@chello.nl>, general@lists.openfabrics.org,
       Steve Wise <swise@opengridcomputing.com>,
       Roland Dreier <rdreier@cisco.com>, Kanoj Sarcar <kanojsarcar@yahoo.com>,
       linux-kernel@vger.kernel.org, linux-mm@kvack.org,
       daniel.blueman@quadrics.com
Subject: Re: [PATCH] mmu notifiers #v7
In-Reply-To: <20080229004001.GN8091@v2.random>
Message-ID: <Pine.LNX.4.64.0802281700060.1954@schroedinger.engr.sgi.com>
References: <20080219084357.GA22249@wotan.suse.de> <20080219135851.GI7128@v2.random>
 <20080219231157.GC18912@wotan.suse.de> <20080220010941.GR7128@v2.random>
 <20080220103942.GU7128@v2.random> <20080221045430.GC15215@wotan.suse.de>
 <20080221144023.GC9427@v2.random> <20080221161028.GA14220@sgi.com>
 <20080227192610.GF28483@v2.random> <Pine.LNX.4.64.0802281456200.1152@schroedinger.engr.sgi.com>
 <20080229004001.GN8091@v2.random>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1435
Lines: 33

On Fri, 29 Feb 2008, Andrea Arcangeli wrote:

> > Also re the _notify variants: The binding to pte_clear_flush_young etc 
> > will become a problem for notifiers that want to sleep because 
> > pte_clear_flush is usually called with the pte lock held. See f.e. 
> > try_to_unmap_one, page_mkclean_one etc.
> 
> Calling __free_page out of the PT lock is much bigger
> change. do_wp_page will require changes anyway when the sleepable
> notifiers are merged.

I thought you wanted to get rid of the sync via pte lock?
What changes to do_wp_page do you envision?

> > It would be better if the notifier calls could be moved outside of the 
> > pte lock.
> 
> The point is that it can't make a difference right now, and my
> objective was to avoid unnecessary source code duplication (later it
> will be necessary, right now it isn't). By the time you rework
> do_wp_page, removing _notify will be a very minor detail compared to
> the rest of the changes to do_wp_page IMHO. Expanding it now won't
> provide a real advantage later.

What is the trouble with the current do_wp_page modifications? There is 
no need for invalidate_page() there so far. invalidate_range() does the 
trick there.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/