From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id 62CC96B004F for ; Thu, 15 Oct 2009 18:17:23 -0400 (EDT) Date: Thu, 15 Oct 2009 23:17:20 +0100 (BST) From: Hugh Dickins Subject: Re: [PATCH 6/9] swap_info: swap_map of chars not shorts In-Reply-To: <20091015114435.9470890a.kamezawa.hiroyu@jp.fujitsu.com> Message-ID: References: <20091015114435.9470890a.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Thu, 15 Oct 2009, KAMEZAWA Hiroyuki wrote: > On Thu, 15 Oct 2009 01:53:52 +0100 (BST) > Hugh Dickins wrote: > > @@ -1175,6 +1175,12 @@ static int try_to_unuse(unsigned int typ > > * If that's wrong, then we should worry more about > > * exit_mmap() and do_munmap() cases described above: > > * we might be resetting SWAP_MAP_MAX too early here. > > + * > > + * Yes, that's wrong: though very unlikely, swap count 0x7ffe > > + * could surely occur if pid_max raised from PID_MAX_DEFAULT; > > Just a nitpick. > > Hmm, logically, our MAX COUNT is 0x7e after this patch. Then, how about not > mentioning to 0x7ffe and PID_MAX ? as.. > > Yes, that's wrong: we now use SWAP_MAP_MAX as 0x7e, very easy to overflow. > next patch will... Perhaps we're reading it differently: I was there inserting a comment on what was already said above (with no wish to change that existing comment), then going on (immediately below) to mention how this patch is now lowering SWAP_MAP_MAX to 0x7e, making the situation even worse, but no worries because the next patch fixes it. If you are seeing a nit there, I'm afraid it's one too small for my eye! And the lifetime of this comment, in Linus's git history, will be (I'm guessing) a fraction of a second - becoming a non-issue, it rightly gets deleted in the next patch. Hugh > > Reviewed-by: KAMEZAWA Hiroyuki > > > + * and we are now lowering SWAP_MAP_MAX to 0x7e, making it > > + * much easier to reach. But the next patch will fix that. -- 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