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=-3.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 CF184C2BA1A for ; Tue, 7 Apr 2020 03:09:07 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9412B20936 for ; Tue, 7 Apr 2020 03:09:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="ByPs8V/S" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9412B20936 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 438DE8E0064; Mon, 6 Apr 2020 23:09:07 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3E8918E0062; Mon, 6 Apr 2020 23:09:07 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2FFCF8E0064; Mon, 6 Apr 2020 23:09:07 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0083.hostedemail.com [216.40.44.83]) by kanga.kvack.org (Postfix) with ESMTP id 1181D8E0062 for ; Mon, 6 Apr 2020 23:09:07 -0400 (EDT) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id BE795181AEF31 for ; Tue, 7 Apr 2020 03:09:06 +0000 (UTC) X-FDA: 76679577492.05.sink34_89bc530c0a963 X-HE-Tag: sink34_89bc530c0a963 X-Filterd-Recvd-Size: 3685 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf50.hostedemail.com (Postfix) with ESMTP for ; Tue, 7 Apr 2020 03:09:06 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7AF8520936; Tue, 7 Apr 2020 03:09:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586228945; bh=AXuOIJMqfwuu0audVmz2JehRm+IwAcwPlZmSvposi6M=; h=Date:From:To:Subject:In-Reply-To:From; b=ByPs8V/SYCzv/8/fSXQzAYaUai8gMy/jAjcSYMIFsxJwZs7P0qG77ckN5cgKI4gf/ P72+CkdNtcvRQ564j/Z/B2530X/sXgYMo7KV9P8qfF1y9RAx+d+CnkenBc3UGZOzPY gdCivtcGd4xwIGEWRHgoKRbjYlmFwWVqTL/sqmW8= Date: Mon, 06 Apr 2020 20:09:05 -0700 From: Andrew Morton To: adobriyan@gmail.com, akpm@linux-foundation.org, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 095/166] proc: speed up /proc/*/statm Message-ID: <20200407030905.mtqs9G2wj%akpm@linux-foundation.org> In-Reply-To: <20200406200254.a69ebd9e08c4074e41ddebaf@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Alexey Dobriyan Subject: proc: speed up /proc/*/statm top(1) reads all /proc/*/statm files but kernel threads will always have zeros. Print those zeroes directly without going through seq_put_decimal_ull(). Speed up reading /proc/2/statm (which is kthreadd) is like 3%. My system has more kernel threads than normal processes after booting KDE. Link: http://lkml.kernel.org/r/20200307154435.GA2788@avx2 Signed-off-by: Alexey Dobriyan Signed-off-by: Andrew Morton --- fs/proc/array.c | 39 +++++++++++++++++++++++---------------- 1 file changed, 23 insertions(+), 16 deletions(-) --- a/fs/proc/array.c~proc-speed-up-proc-statm +++ a/fs/proc/array.c @@ -635,28 +635,35 @@ int proc_tgid_stat(struct seq_file *m, s int proc_pid_statm(struct seq_file *m, struct pid_namespace *ns, struct pid *pid, struct task_struct *task) { - unsigned long size = 0, resident = 0, shared = 0, text = 0, data = 0; struct mm_struct *mm = get_task_mm(task); if (mm) { + unsigned long size; + unsigned long resident = 0; + unsigned long shared = 0; + unsigned long text = 0; + unsigned long data = 0; + size = task_statm(mm, &shared, &text, &data, &resident); mmput(mm); - } - /* - * For quick read, open code by putting numbers directly - * expected format is - * seq_printf(m, "%lu %lu %lu %lu 0 %lu 0\n", - * size, resident, shared, text, data); - */ - seq_put_decimal_ull(m, "", size); - seq_put_decimal_ull(m, " ", resident); - seq_put_decimal_ull(m, " ", shared); - seq_put_decimal_ull(m, " ", text); - seq_put_decimal_ull(m, " ", 0); - seq_put_decimal_ull(m, " ", data); - seq_put_decimal_ull(m, " ", 0); - seq_putc(m, '\n'); + /* + * For quick read, open code by putting numbers directly + * expected format is + * seq_printf(m, "%lu %lu %lu %lu 0 %lu 0\n", + * size, resident, shared, text, data); + */ + seq_put_decimal_ull(m, "", size); + seq_put_decimal_ull(m, " ", resident); + seq_put_decimal_ull(m, " ", shared); + seq_put_decimal_ull(m, " ", text); + seq_put_decimal_ull(m, " ", 0); + seq_put_decimal_ull(m, " ", data); + seq_put_decimal_ull(m, " ", 0); + seq_putc(m, '\n'); + } else { + seq_write(m, "0 0 0 0 0 0 0\n", 14); + } return 0; } _