From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with SMTP id 4C3908D0039 for ; Tue, 15 Feb 2011 12:01:55 -0500 (EST) Date: Tue, 15 Feb 2011 18:01:52 +0100 From: Andrea Arcangeli Subject: Re: [PATCH 0/5] fix up /proc/$pid/smaps to not split huge pages Message-ID: <20110215170152.GF5935@random.random> References: <20110209195406.B9F23C9F@kernel> <20110215165510.GA2550@mgebm.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110215165510.GA2550@mgebm.net> Sender: owner-linux-mm@kvack.org List-ID: To: Eric B Munson Cc: Dave Hansen , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Michael J Wolf On Tue, Feb 15, 2011 at 11:55:10AM -0500, Eric B Munson wrote: > I am noticing in smaps that KernelPageSize is wrong of areas > that have been merged into THP. For instance: > > 7ff852a00000-7ff852c00000 rw-p 00000000 00:00 0 > Size: 2048 kB > Rss: 2048 kB > Pss: 2048 kB > Shared_Clean: 0 kB > Shared_Dirty: 0 kB > Private_Clean: 0 kB > Private_Dirty: 2048 kB > Referenced: 2048 kB > Anonymous: 2048 kB > AnonHugePages: 2048 kB > Swap: 0 kB > KernelPageSize: 4 kB > MMUPageSize: 4 kB > Locked: 0 kB > > The entire mapping is contained in a THP but the > KernelPageSize shows 4kb. For cases where the mapping might > have mixed page sizes this may be okay, but for this > particular mapping the 4kb page size is wrong. I'm not sure this is a bug, if the mapping grows it may become 4096k but the new pages may be 4k. There's no such thing as a vma_mmu_pagesize in terms of hugepages because we support graceful fallback and collapse/split on the fly without altering the vma. So I think 4k is correct here. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org