From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f51.google.com (mail-wm0-f51.google.com [74.125.82.51]) by kanga.kvack.org (Postfix) with ESMTP id 23486828E8 for ; Tue, 9 Feb 2016 04:10:09 -0500 (EST) Received: by mail-wm0-f51.google.com with SMTP id p63so13799559wmp.1 for ; Tue, 09 Feb 2016 01:10:09 -0800 (PST) Received: from mail-wm0-x242.google.com (mail-wm0-x242.google.com. [2a00:1450:400c:c09::242]) by mx.google.com with ESMTPS id da7si47662800wjb.185.2016.02.09.01.10.07 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 09 Feb 2016 01:10:07 -0800 (PST) Received: by mail-wm0-x242.google.com with SMTP id 128so2145816wmz.3 for ; Tue, 09 Feb 2016 01:10:07 -0800 (PST) Date: Tue, 9 Feb 2016 10:10:03 +0100 From: Ingo Molnar Subject: Re: [PATCH] x86/mm/vmfault: Make vmalloc_fault() handle large pages Message-ID: <20160209091003.GA10774@gmail.com> References: <1454976038-22486-1-git-send-email-toshi.kani@hpe.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1454976038-22486-1-git-send-email-toshi.kani@hpe.com> Sender: owner-linux-mm@kvack.org List-ID: To: Toshi Kani Cc: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, bp@alien8.de, henning.schild@siemens.com, linux-nvdimm@lists.01.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org * Toshi Kani wrote: > Since 4.1, ioremap() supports large page (pud/pmd) mappings in x86_64 and PAE. > vmalloc_fault() however assumes that the vmalloc range is limited to pte > mappings. > > pgd_ctor() sets the kernel's pgd entries to user's during fork(), which makes > user processes share the same page tables for the kernel ranges. When a call to > ioremap() is made at run-time that leads to allocate a new 2nd level table (pud > in 64-bit and pmd in PAE), user process needs to re-sync with the updated kernel > pgd entry with vmalloc_fault(). > > Following changes are made to vmalloc_fault(). So what were the effects of this shortcoming? Were large page ioremap()s unusable? Was this harmless because no driver used this facility? If so then the changelog needs to spell this out clearly ... Thanks, Ingo -- 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