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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 26B1CC43219 for ; Fri, 26 Apr 2019 19:02:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 032EC208CA for ; Fri, 26 Apr 2019 19:02:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726724AbfDZTCU (ORCPT ); Fri, 26 Apr 2019 15:02:20 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48940 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726252AbfDZTCT (ORCPT ); Fri, 26 Apr 2019 15:02:19 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id BF93A308B772; Fri, 26 Apr 2019 19:02:18 +0000 (UTC) Received: from jsavitz.bos.com (dhcp-17-3.bos.redhat.com [10.18.17.3]) by smtp.corp.redhat.com (Postfix) with ESMTP id 112A6600C8; Fri, 26 Apr 2019 19:02:14 +0000 (UTC) From: Joel Savitz To: linux-kernel@vger.kernel.org Cc: Joel Savitz , Alexey Dobriyan , Andrew Morton , Vlastimil Babka , "Aneesh Kumar K.V" , Michael Ellerman , Ram Pai , Andrea Arcangeli , Huang Ying , Sandeep Patil , Rafael Aquini , linux-fsdevel@vger.kernel.org Subject: [PATCH v2] fs/proc: add VmTaskSize field to /proc/$$/status Date: Fri, 26 Apr 2019 15:02:08 -0400 Message-Id: <1556305328-2001-1-git-send-email-jsavitz@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.47]); Fri, 26 Apr 2019 19:02:18 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In the mainline kernel, there is no quick mechanism to get the virtual memory size of the current process from userspace. Despite the current state of affairs, this information is available to the user through several means, one being a linear search of the entire address space. This is an inefficient use of cpu cycles. A component of the libhugetlb kernel test does exactly this, and as systems' address spaces increase beyond 32-bits, this method becomes exceedingly tedious. For example, on a ppc64le system with a 47-bit address space, the linear search causes the test to hang for some unknown amount of time. I couldn't give you an exact number because I just ran it for about 10-20 minutes and went to go do something else, probably to get coffee or something, and when I came back, I just killed the test and patched it to use this new mechanism. I re-ran my new version of the test using a kernel with this patch, and of course it passed through the previously bottlenecking codepath nearly instantaneously. This patched enabled me to upgrade an O(n) codepath to O(1) in an architecture-independent manner. Signed-off-by: Joel Savitz --- Documentation/filesystems/proc.txt | 2 ++ fs/proc/task_mmu.c | 5 ++++- 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index 66cad5c86171..1c6a912e3975 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -187,6 +187,7 @@ read the file /proc/PID/status: VmLib: 1412 kB VmPTE: 20 kb VmSwap: 0 kB + VmTaskSize: 137438953468 kB HugetlbPages: 0 kB CoreDumping: 0 THP_enabled: 1 @@ -263,6 +264,7 @@ Table 1-2: Contents of the status files (as of 4.19) VmPTE size of page table entries VmSwap amount of swap used by anonymous private data (shmem swap usage is not included) + VmTaskSize size of entire virtual address space of a process HugetlbPages size of hugetlb memory portions CoreDumping process's memory is currently being dumped (killing the process may lead to a corrupted core) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 95ca1fe7283c..0ddd51479f90 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