From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by uproxy.gmail.com with SMTP id m2so24188uge for ; Tue, 21 Mar 2006 22:02:44 -0800 (PST) Message-ID: Date: Wed, 22 Mar 2006 01:02:44 -0500 From: "Stone Wang" Subject: Re: [PATCH][5/8] proc: export mlocked pages info through "/proc/meminfo: Wired" In-Reply-To: <1142977393.10906.204.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Content-Disposition: inline References: <1142977393.10906.204.camel@localhost.localdomain> Sender: owner-linux-mm@kvack.org Return-Path: To: Dave Hansen Cc: akpm@osdl.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: 2006/3/21, Dave Hansen : > On Mon, 2006-03-20 at 08:37 -0500, Stone Wang wrote: > > --- linux-2.6.15.orig/include/linux/mm.h 2006-01-02 22:21:10.000000000 -0500 > > +++ linux-2.6.15/include/linux/mm.h 2006-03-07 01:49:12.000000000 -0500 > > @@ -218,6 +221,10 @@ > > unsigned long flags; /* Atomic flags, some possibly > > * updated asynchronously */ > > atomic_t _count; /* Usage count, see below. */ > > + unsigned short wired_count; /* Count of wirings of the page. > > + * If not zero,the page would be SetPageWired, > > + * and put on Wired list of the zone. > > + */ > > atomic_t _mapcount; /* Count of ptes mapped in mms, > > * to show when page is mapped > > * & limit reverse map searches. > > We're usually pretty picky about adding stuff to 'struct page'. It > _just_ fits inside a cacheline on most 32-bit architectures. > > Can this wired_count not be derived at runtime? It seems like it would > be possible to run through all VMAs mapping the page, and determining > how many of them are VM_LOCKED. Would that be too slow? It can be derived, but perhaps would made code not that clear. I will try accroding to your comments, and i think there could be fast scanning of the vma list for this purpose. > Also, does it matter how many times it is locked, or just that > _somebody_ has it locked? For now, it just matters somebody has it locked. When munlock a page, it matters somebody else has it locked. > > -- Dave > > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org