Date: Mon, 14 May 2007 13:46:06 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Theodore Tso <tytso@mit.edu>
Cc: Fengguang Wu <fengguang.wu@gmail.com>, linux-kernel@vger.kernel.org,
       linux-mm@kvack.org, Rik van Riel <riel@redhat.com>,
       "linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>,
       Nick Piggin <nickpiggin@yahoo.com.au>
Subject: Re: [PATCH] resolve duplicate flag no for PG_lazyfree
Message-Id: <20070514134606.695f087a.akpm@linux-foundation.org>
In-Reply-To: <20070514180618.GB9399@thunk.org>
References: <379110250.28666@ustc.edu.cn>
	<20070513224630.3cd0cb54.akpm@linux-foundation.org>
	<20070514180618.GB9399@thunk.org>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1474
Lines: 34

On Mon, 14 May 2007 14:06:19 -0400
Theodore Tso <tytso@mit.edu> wrote:

> On Sun, May 13, 2007 at 10:46:30PM -0700, Andrew Morton wrote:
> > otoh, the intersection between pages which are PageBooked() and pages which
> > are PageLazyFree() should be zreo, so it'd be good to actually formalise
> > this reuse within the ext4 patches.
> > 
> > otoh2, PageLazyFree() could have reused PG_owner_priv_1.
> > 
> > Rik, Ted: any thoughts?  We do need to scrimp on page flags: when we
> > finally run out, we're screwed.
> 
> It makes sense to me.  PG_lazyfree is currently only in -mm, right?

Ah, yes, I got confused, sorry.

>  I
> don't see it in my git tree.  It would probably would be a good idea
> to make sure that we check to add some sanity checking code if it
> isn't there already that PG_lazyfree isn't already set when try to set
> PG_lazyfree (just in case there is a bug in the future which causes
> the should-never-happen case of trying lazy free a PageBooked page).
> 

Actually, I think the current status of
lazy-freeing-of-memory-through-madv_free.patch is "might not be needed".  I
_think_ we've determined that 0a27a14a62921b438bb6f33772690d345a089be6
sufficiently fixed the perfomance problems we had in 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/