From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f198.google.com (mail-wr0-f198.google.com [209.85.128.198]) by kanga.kvack.org (Postfix) with ESMTP id 6A6F96B0003 for ; Fri, 16 Feb 2018 18:57:56 -0500 (EST) Received: by mail-wr0-f198.google.com with SMTP id 30so2447483wrw.6 for ; Fri, 16 Feb 2018 15:57:56 -0800 (PST) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTPS id h202si3167534wme.236.2018.02.16.15.57.54 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 16 Feb 2018 15:57:55 -0800 (PST) Date: Fri, 16 Feb 2018 15:57:52 -0800 From: Andrew Morton Subject: Re: [PATCH] proc/kpageflags: add KPF_WAITERS Message-Id: <20180216155752.4a17cfd41875911c79807585@linux-foundation.org> In-Reply-To: <151834540184.176427.12174649162560874101.stgit@buzz> References: <151834540184.176427.12174649162560874101.stgit@buzz> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Konstantin Khlebnikov Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Naoya Horiguchi , Michal Hocko , Linus Torvalds , "Kirill A. Shutemov" , Nicholas Piggin On Sun, 11 Feb 2018 13:36:41 +0300 Konstantin Khlebnikov wrote: > KPF_WAITERS indicates tasks are waiting for a page lock or writeback. > This might be false-positive, in this case next unlock will clear it. Well, kpageflags is full of potential false-positives. Or do you think this flag is especially vulnerable? In other words, under what circumstances will we have KPF_WAITERS set when PG_locked and PG-writeback are clear? > This looks like worth information not only for kernel hacking. Why? What are the use-cases, in detail? How are we to justify this modification? > In tool page-types in non-raw mode treat KPF_WAITERS without > KPF_LOCKED and KPF_WRITEBACK as false-positive and hide it. > fs/proc/page.c | 1 + > include/uapi/linux/kernel-page-flags.h | 1 + > tools/vm/page-types.c | 7 +++++++ Please update Documentation/vm/pagemap.txt. -- 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