From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f199.google.com (mail-io0-f199.google.com [209.85.223.199]) by kanga.kvack.org (Postfix) with ESMTP id 3AD7A6B0005 for ; Tue, 10 May 2016 16:30:12 -0400 (EDT) Received: by mail-io0-f199.google.com with SMTP id k129so52662147iof.0 for ; Tue, 10 May 2016 13:30:12 -0700 (PDT) Received: from mail-oi0-x235.google.com (mail-oi0-x235.google.com. [2607:f8b0:4003:c06::235]) by mx.google.com with ESMTPS id h205si1338810oib.211.2016.05.10.13.30.11 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 10 May 2016 13:30:11 -0700 (PDT) Received: by mail-oi0-x235.google.com with SMTP id v145so35478473oie.0 for ; Tue, 10 May 2016 13:30:11 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20160510182055.GA24868@redhat.com> References: <20160510182055.GA24868@redhat.com> From: Andy Lutomirski Date: Tue, 10 May 2016 13:29:50 -0700 Message-ID: Subject: Re: Getting rid of dynamic TASK_SIZE (on x86, at least) Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Oleg Nesterov Cc: Cyrill Gorcunov , Pavel Emelyanov , Dmitry Safonov <0x7f454c46@gmail.com>, Borislav Petkov , "linux-mm@kvack.org" , X86 ML , Ruslan Kabatsayev , "linux-kernel@vger.kernel.org" On May 10, 2016 11:21 AM, "Oleg Nesterov" wrote: > > On 05/10, Andy Lutomirski wrote: > > > > - xol_add_vma: This one is weird: uprobes really is doing something > > behind the task's back, and the addresses need to be consistent with > > the address width. I'm not quite sure what to do here. > > It can use mm->task_size instead, plus this is just a hint. And perhaps > mm->task_size should have more users, say get_unmapped_area... Ick. I hadn't noticed mm->task_size. We have a *lot* of different indicators of task size. mm->task_size appears to have basically no useful uses except maybe for ppc. On x86, bitness can change without telling the kernel, and tasks running in 64-bit mode can do 32-bit syscalls. So maybe I should add mm->task_size to my list of things that would be nice to remove. Or maybe I'm just tilting at windmills. > > Not sure we should really get rid of dynamic TASK_SIZE completely, but > personally I agree it looks a bit ugly. > > Oleg. > -- 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