From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f174.google.com (mail-pf0-f174.google.com [209.85.192.174]) by kanga.kvack.org (Postfix) with ESMTP id 4A71F6B0264 for ; Tue, 15 Mar 2016 11:31:05 -0400 (EDT) Received: by mail-pf0-f174.google.com with SMTP id n5so33186221pfn.2 for ; Tue, 15 Mar 2016 08:31:05 -0700 (PDT) Received: from mga01.intel.com (mga01.intel.com. [192.55.52.88]) by mx.google.com with ESMTP id n2si5705999pap.201.2016.03.15.08.31.03 for ; Tue, 15 Mar 2016 08:31:03 -0700 (PDT) Subject: Re: [PATCH] thp, mlock: update unevictable-lru.txt References: <1458053744-40664-1-git-send-email-kirill.shutemov@linux.intel.com> From: Dave Hansen Message-ID: <56E82AAE.8090003@intel.com> Date: Tue, 15 Mar 2016 08:30:54 -0700 MIME-Version: 1.0 In-Reply-To: <1458053744-40664-1-git-send-email-kirill.shutemov@linux.intel.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" , Andrew Morton Cc: linux-mm@kvack.org On 03/15/2016 07:55 AM, Kirill A. Shutemov wrote: > +Transparent huge page is represented by single entry on a lru list and > +therefore we can only make unevictable entire compound page, not > +individual subpages. A few grammar nits: A transparent huge page is represented by a single entry on an lru list. Therefore, we can only make unevictable an entire compound page, not individual subpages. ... > +We handle this by forbidding mlocking PTE-mapped huge pages. This way we > +keep the huge page accessible for vmscan. Under memory pressure the page > +will be split, subpages from VM_LOCKED VMAs moved to unevictable lru and > +the rest can be evicted. What do you mean by "mlocking" in this context? Do you mean that we actually return -ESOMETHING from mlock() on PTE-mapped huge pages? Or, do you just mean that we defer treating PTE-mapped huge pages as PageUnevictable() inside the kernel? I think we should probably avoid saying "mlocking" when we really mean "kernel-internal mlocked page handling" aka. the unevictable list. -- 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