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 ESMTP id 904EC6B0011 for ; Wed, 4 May 2011 13:28:37 -0400 (EDT) Received: from hpaq12.eem.corp.google.com (hpaq12.eem.corp.google.com [172.25.149.12]) by smtp-out.google.com with ESMTP id p44HSZue001686 for ; Wed, 4 May 2011 10:28:35 -0700 Received: from pzk35 (pzk35.prod.google.com [10.243.19.163]) by hpaq12.eem.corp.google.com with ESMTP id p44HS6gc026598 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=NOT) for ; Wed, 4 May 2011 10:28:33 -0700 Received: by pzk35 with SMTP id 35so2236047pzk.25 for ; Wed, 04 May 2011 10:28:33 -0700 (PDT) Date: Wed, 4 May 2011 10:28:36 -0700 (PDT) From: Hugh Dickins Subject: Re: [PATCH resend] mm: get rid of CONFIG_STACK_GROWSUP || CONFIG_IA64 In-Reply-To: <20110504083005.GA1375@tiehlicka.suse.cz> Message-ID: References: <20110503141044.GA25351@tiehlicka.suse.cz> <20110504083005.GA1375@tiehlicka.suse.cz> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Andrew Morton , linux-mm@kvack.org, LKML On Wed, 4 May 2011, Michal Hocko wrote: > > This case is obscure enough already because we are using VM_GROWSUP to > declare expand_stack_upwards in include/linux/mm.h Ah yes, I didn't notice that it was already done that way there (closer to the definitions of VM_GROWSUP so not as bad). > while definition is guarded by CONFIG_STACK_GROWSUP||CONFIG_IA64. > What the patch does is just "make it consistent" thing. I think we > should at least use CONFIG_STACK_GROWSUP||CONFIG_IA64 at both places if > you do not like VM_GROWSUP misuse. If it's worth changing anything, yes, that would be better. > > > Not a nack: others may well disagree with me. > > > > And, though I didn't find time to comment on your later "symmetrical" > > patch before it went into mmotm, I didn't see how renaming expand_downwards > > and expand_upwards to expand_stack_downwards and expand_stack_upwards was > > helpful either - needless change, and you end up using expand_stack_upwards > > on something which is not (what we usually call) the stack. > > OK, I see your point. expand_stack_upwards in ia64_do_page_fault can be > confusing as well. Maybe if we stick with the original expand_upwards > and just make expand_downwards symmetrical without renameing to > "_stack_" like the patch does? I can rework that patch if there is an > interest. I would like to have it symmetrical, though, because the > original code was rather confusing. Yes, what I suggested before was an expand_upwards, an expand_downwards and an expand_stack (with mod to fs/exec.c to replace its call to expand_stack_downwards by direct call to expand_downwards). But it's always going to be somewhat confusing and asymmetrical because of the ia64 register backing store case. Hugh -- 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