From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CE523C43219 for ; Thu, 25 Apr 2019 21:00:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D752D206BF for ; Thu, 25 Apr 2019 21:00:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728895AbfDYVAt (ORCPT ); Thu, 25 Apr 2019 17:00:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49706 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726282AbfDYVAs (ORCPT ); Thu, 25 Apr 2019 17:00:48 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 27895307D85A; Thu, 25 Apr 2019 21:00:48 +0000 (UTC) Received: from x230.aquini.net (ovpn-126-47.rdu2.redhat.com [10.10.126.47]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 10A1F171C5; Thu, 25 Apr 2019 21:00:44 +0000 (UTC) Date: Thu, 25 Apr 2019 17:00:43 -0400 From: Rafael Aquini To: Joel Savitz Cc: linux-kernel@vger.kernel.org, Alexey Dobriyan , Andrew Morton , Vlastimil Babka , "Aneesh Kumar K.V" , Michael Ellerman , Ram Pai , Andrea Arcangeli , Huang Ying , Sandeep Patil , linux-fsdevel@vger.kernel.org Subject: Re: [PATCH] fs/proc: add VmTaskSize field to /proc/$$/status Message-ID: <20190425210043.GB4546@x230.aquini.net> References: <1556225867-458-1-git-send-email-jsavitz@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1556225867-458-1-git-send-email-jsavitz@redhat.com> User-Agent: Mutt/1.11.3 (2019-02-01) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.48]); Thu, 25 Apr 2019 21:00:48 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 25, 2019 at 04:57:47PM -0400, Joel Savitz wrote: > Currently, there is no fast mechanism to get the virtual memory size of > the current process from userspace. This information is available to the > user through several means, one being a linear search of the entire address > space. This is the method used by a component of the libhugetlb kernel > test, and using the mechanism proposed in this patch, the time complexity > of that test would be upgraded to constant time from linear time. This is > especially relevant on 64-bit architechtures where a linear search of > the address space could take an absurd amount of time. Using this > mechanism, the modification to the test component would be portable > across all architechtures. > > Signed-off-by: Joel Savitz > --- > fs/proc/task_mmu.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > index 92a91e7816d8..f64b9a949624 100644 > --- a/fs/proc/task_mmu.c > +++ b/fs/proc/task_mmu.c > @@ -74,7 +74,10 @@ void task_mem(struct seq_file *m, struct mm_struct *mm) > seq_put_decimal_ull_width(m, > " kB\nVmPTE:\t", mm_pgtables_bytes(mm) >> 10, 8); > SEQ_PUT_DEC(" kB\nVmSwap:\t", swap); > - seq_puts(m, " kB\n"); > + SEQ_PUT_DEC(" kB\nVmSwap:\t", swap); > + seq_put_decimal_ull_width(m, > + " kB\nVmTaskSize:\t", TASK_SIZE >> 10, 8); > + seq_puts(m, " kB\n"); > hugetlb_report_usage(m, mm); > } > #undef SEQ_PUT_DEC > -- > 2.18.1 > Acked-by: Rafael Aquini