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=-6.8 required=3.0 tests=BAYES_00,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 421E9C43457 for ; Tue, 13 Oct 2020 23:51:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0140522201 for ; Tue, 13 Oct 2020 23:51:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602633088; bh=bX7VzBOzh53KeWxHAEHq2ingEbvqR0h7IECo0hgmsos=; h=Date:From:To:Subject:In-Reply-To:Reply-To:List-ID:From; b=aQNFB67T6UKzTF4kj6RayWhQEpziuxZkV2QL9shktQ985uALQV3SgYOhD/iwWcaD8 g/NxuWE+5oRWlVg8IiIcCqtxMMIZbw6jFEfeRrF866AmwON5EYl2ZZorE/dRuvYHyq BQK1OgitSAS9tCZmjpX2U8v0prwIxYhUUFgJDN4Y= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730151AbgJMXv1 (ORCPT ); Tue, 13 Oct 2020 19:51:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:36248 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730421AbgJMXv0 (ORCPT ); Tue, 13 Oct 2020 19:51:26 -0400 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 32E4D21D7A; Tue, 13 Oct 2020 23:51:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602633085; bh=bX7VzBOzh53KeWxHAEHq2ingEbvqR0h7IECo0hgmsos=; h=Date:From:To:Subject:In-Reply-To:From; b=rmOq18sL0cdiwXH/LXHVJt6eS1o6gn3hfwfA/lmWGeC4syeGdzAxletgmIkidPaNX QpBXy+Nt26OjYY9ZHquXj20zQOCtO12Tc6klOFxzlwtkbclqFQ8pbYZhA0PoBXqBpW 2YjpaRER7DXcVYJlRVYN8o/VxEbt7EokLValB5vA= Date: Tue, 13 Oct 2020 16:51:24 -0700 From: Andrew Morton To: adobriyan@gmail.com, akpm@linux-foundation.org, cai@redhat.com, chris@chris-wilson.co.uk, hannes@cmpxchg.org, hughd@google.com, jani.nikula@linux.intel.com, linux-mm@kvack.org, matthew.auld@intel.com, mm-commits@vger.kernel.org, torvalds@linux-foundation.org, william.kucharski@oracle.com, willy@infradead.org, ying.huang@intel.com Subject: [patch 056/181] mm: optimise madvise WILLNEED Message-ID: <20201013235124.9efI4nvew%akpm@linux-foundation.org> In-Reply-To: <20201013164658.3bfd96cc224d8923e66a9f4e@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: "Matthew Wilcox (Oracle)" Subject: mm: optimise madvise WILLNEED Instead of calling find_get_entry() for every page index, use an XArray iterator to skip over NULL entries, and avoid calling get_page(), because we only want the swap entries. [willy@infradead.org: fix LTP soft lockups] Link: https://lkml.kernel.org/r/20200914165032.GS6583@casper.infradead.org Link: https://lkml.kernel.org/r/20200910183318.20139-4-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Acked-by: Johannes Weiner Cc: Alexey Dobriyan Cc: Chris Wilson Cc: Huang Ying Cc: Hugh Dickins Cc: Jani Nikula Cc: Matthew Auld Cc: William Kucharski Cc: Qian Cai Signed-off-by: Andrew Morton --- mm/madvise.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) --- a/mm/madvise.c~mm-optimise-madvise-willneed +++ a/mm/madvise.c @@ -224,25 +224,28 @@ static void force_shm_swapin_readahead(s unsigned long start, unsigned long end, struct address_space *mapping) { - pgoff_t index; + XA_STATE(xas, &mapping->i_pages, linear_page_index(vma, start)); + pgoff_t end_index = end / PAGE_SIZE; struct page *page; - swp_entry_t swap; - for (; start < end; start += PAGE_SIZE) { - index = ((start - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; + rcu_read_lock(); + xas_for_each(&xas, page, end_index) { + swp_entry_t swap; - page = find_get_entry(mapping, index); - if (!xa_is_value(page)) { - if (page) - put_page(page); + if (!xa_is_value(page)) continue; - } + xas_pause(&xas); + rcu_read_unlock(); + swap = radix_to_swp_entry(page); page = read_swap_cache_async(swap, GFP_HIGHUSER_MOVABLE, NULL, 0, false); if (page) put_page(page); + + rcu_read_lock(); } + rcu_read_unlock(); lru_add_drain(); /* Push any new pages onto the LRU now */ } _