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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,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 A4EDDC433EF for ; Wed, 8 Sep 2021 02:59:41 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 58B2261100 for ; Wed, 8 Sep 2021 02:59:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 58B2261100 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=kvack.org Received: by kanga.kvack.org (Postfix) id EE80A94004C; Tue, 7 Sep 2021 22:59:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E971A940042; Tue, 7 Sep 2021 22:59:40 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DAD2D94004C; Tue, 7 Sep 2021 22:59:40 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0126.hostedemail.com [216.40.44.126]) by kanga.kvack.org (Postfix) with ESMTP id CB65B940042 for ; Tue, 7 Sep 2021 22:59:40 -0400 (EDT) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 8D76A8249980 for ; Wed, 8 Sep 2021 02:59:40 +0000 (UTC) X-FDA: 78562900920.09.1D3155E Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf21.hostedemail.com (Postfix) with ESMTP id 4B478D0299C4 for ; Wed, 8 Sep 2021 02:59:40 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 3529B60E52; Wed, 8 Sep 2021 02:59:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1631069979; bh=i/DUiz9NGfmBq7XEEaSuMcvtOWFd3bWSINFttnMqYrs=; h=Date:From:To:Subject:In-Reply-To:From; b=gzC0bU+BLMfLqUWIIwv3C0HS8GFhQQkRuBSD5XKe/hP2L4F5LW3oFWb5cV6V54L4V tgO2UPhoQM6uYFkX2tss04jpUIhFqNi1ziympHVpLroVc8KdFHRvZFiS1OLNgw+fxz +kcZ/w1EXOJTVVyzYksi63vecfnGcBTluz8y5NXc= Date: Tue, 07 Sep 2021 19:59:38 -0700 From: Andrew Morton To: aklimov@redhat.com, akpm@linux-foundation.org, alobakin@pm.me, andriy.shevchenko@linux.intel.com, dennis@kernel.org, jolsa@redhat.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org, ulf.hansson@linaro.org, will@kernel.org, wsa+renesas@sang-engineering.com, yury.norov@gmail.com Subject: [patch 120/147] mm/percpu: micro-optimize pcpu_is_populated() Message-ID: <20210908025938.FF_oXJh3P%akpm@linux-foundation.org> In-Reply-To: <20210907195226.14b1d22a07c085b22968b933@linux-foundation.org> User-Agent: s-nail v14.8.16 Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=gzC0bU+B; spf=pass (imf21.hostedemail.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none X-Stat-Signature: tn8seafm7paxdq9wowouigzsux9ai3mr X-Rspamd-Queue-Id: 4B478D0299C4 X-Rspamd-Server: rspam04 X-HE-Tag: 1631069980-637614 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: Yury Norov Subject: mm/percpu: micro-optimize pcpu_is_populated() bitmap_next_clear_region() calls find_next_zero_bit() and find_next_bit() sequentially to find a range of clear bits. In case of pcpu_is_populated() there's a chance to return earlier if bitmap has all bits set. Link: https://lkml.kernel.org/r/20210814211713.180533-15-yury.norov@gmail.com Signed-off-by: Yury Norov Tested-by: Wolfram Sang Acked-by: Dennis Zhou Cc: Alexander Lobakin Cc: Alexey Klimov Cc: Andy Shevchenko Cc: Jiri Olsa Cc: Ulf Hansson Cc: Will Deacon Signed-off-by: Andrew Morton --- mm/percpu.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) --- a/mm/percpu.c~mm-percpu-micro-optimize-pcpu_is_populated +++ a/mm/percpu.c @@ -1070,17 +1070,18 @@ static void pcpu_block_update_hint_free( static bool pcpu_is_populated(struct pcpu_chunk *chunk, int bit_off, int bits, int *next_off) { - unsigned int page_start, page_end, rs, re; + unsigned int start, end; - page_start = PFN_DOWN(bit_off * PCPU_MIN_ALLOC_SIZE); - page_end = PFN_UP((bit_off + bits) * PCPU_MIN_ALLOC_SIZE); + start = PFN_DOWN(bit_off * PCPU_MIN_ALLOC_SIZE); + end = PFN_UP((bit_off + bits) * PCPU_MIN_ALLOC_SIZE); - rs = page_start; - bitmap_next_clear_region(chunk->populated, &rs, &re, page_end); - if (rs >= page_end) + start = find_next_zero_bit(chunk->populated, end, start); + if (start >= end) return true; - *next_off = re * PAGE_SIZE / PCPU_MIN_ALLOC_SIZE; + end = find_next_bit(chunk->populated, end, start + 1); + + *next_off = end * PAGE_SIZE / PCPU_MIN_ALLOC_SIZE; return false; } _