From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 27 Jan 2007 09:08:58 +0000 (GMT) From: Hugh Dickins Subject: Re: [PATCH] Don't allow the stack to grow into hugetlb reserved regions In-Reply-To: Message-ID: References: <20070125214052.22841.33449.stgit@localhost.localdomain> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Ken Chen Cc: Adam Litke , Andrew Morton , William Irwin , David Gibson , linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Fri, 26 Jan 2007, Ken Chen wrote: > On 1/26/07, Hugh Dickins wrote: > > Less trivial (and I wonder whether you've come to this from an ia64 > > or a powerpc direction): I notice that ia64 has more stringent REGION > > checks in its ia64_do_page_fault, before calling expand_stack or > > expand_upwards. So on that path, the usual path, I think your > > new check in acct_stack_growth is unnecessary on ia64; > > I think you are correct. This appears to affect powerpc only. On ia64, > hugetlb lives in a completely different region and they can never step > into normal stack address space. And for x86, there isn't a thing called > "reserved address space" for hugetlb mapping. Thanks, that's reassuring for the hugetlb case, and therefore Adam's patch should not be delayed. But it does leave open the question I was raising in the text you've snipped: if ia64 needs those stringent REGION checks in its ia64_do_page_fault path, don't we need to add them some(messy)how in the get_user_pages find_extend_vma path? 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/ . Don't email: email@kvack.org