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=-12.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 9BA9BC43461 for ; Mon, 14 Sep 2020 13:07:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4AE83208E4 for ; Mon, 14 Sep 2020 13:07:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="gDn66Rgt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726713AbgINNHW (ORCPT ); Mon, 14 Sep 2020 09:07:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52524 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726559AbgINNBo (ORCPT ); Mon, 14 Sep 2020 09:01:44 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 603FAC06121C for ; Mon, 14 Sep 2020 06:01:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=EHgzdRosBMsz0w0GEEdwo/W7ei2Jp7MgX6g3BY09CJk=; b=gDn66RgtJXXmxOQbT+bHpRicPg QRqGFAlitj5356PJyc2I/jZtYMdlOl5H0SZ+QgfNlzqtRSKr7WmwCx71OAgBP7AyW2Urvi2EuSWJl pqRXY5QxeF9sHBXEu8CybYYVGJ6L+ly6sSEz9w1t5aR7/zGkyLHvv4XRAxdKulMEqYxSezQBfahD5 hgQKwQpB3Bc426SoBubGjDftU5Qwjau0qPy/5V+dGTS4TAZB2Vnwc/T69ei3uBRZqPuioJ7fiN+4t pysdnw4fBtaxKOaKz0D5+4roBgqXqOR+D95NhFXMT2xMD83P69s5A+cG1dNtjiFDYdt/4OzjR13XF QP4v67MQ==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kHo68-0002zr-Th; Mon, 14 Sep 2020 13:00:44 +0000 From: "Matthew Wilcox (Oracle)" To: linux-mm@kvack.org Cc: "Matthew Wilcox (Oracle)" , Andrew Morton , Hugh Dickins , William Kucharski , Johannes Weiner , Jan Kara , Yang Shi , Dave Chinner , linux-kernel@vger.kernel.org Subject: [PATCH v2 03/12] mm/filemap: Add helper for finding pages Date: Mon, 14 Sep 2020 14:00:33 +0100 Message-Id: <20200914130042.11442-4-willy@infradead.org> X-Mailer: git-send-email 2.21.3 In-Reply-To: <20200914130042.11442-1-willy@infradead.org> References: <20200914130042.11442-1-willy@infradead.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There is a lot of common code in find_get_entries(), find_get_pages_range() and find_get_pages_range_tag(). Factor out xas_find_get_entry() which simplifies all three functions. Signed-off-by: Matthew Wilcox (Oracle) --- mm/filemap.c | 98 +++++++++++++++++++++++----------------------------- 1 file changed, 43 insertions(+), 55 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index 7d8cf1a25628..d8f5ff07eb9c 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1758,6 +1758,43 @@ struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index, } EXPORT_SYMBOL(pagecache_get_page); +static inline struct page *xas_find_get_entry(struct xa_state *xas, + pgoff_t max, xa_mark_t mark) +{ + struct page *page; + +retry: + if (mark == XA_PRESENT) + page = xas_find(xas, max); + else + page = xas_find_marked(xas, max, mark); + + if (xas_retry(xas, page)) + goto retry; + /* + * A shadow entry of a recently evicted page, a swap + * entry from shmem/tmpfs or a DAX entry. Return it + * without attempting to raise page count. + */ + if (!page || xa_is_value(page)) + return page; + + if (!page_cache_get_speculative(page)) + goto reset; + + /* Has the page moved or been split? */ + if (unlikely(page != xas_reload(xas))) { + put_page(page); + goto reset; + } + VM_BUG_ON_PAGE(!thp_contains(page, xas->xa_index), page); + + return page; +reset: + xas_reset(xas); + goto retry; +} + /** * find_get_entries - gang pagecache lookup * @mapping: The address_space to search @@ -1797,42 +1834,21 @@ unsigned find_get_entries(struct address_space *mapping, return 0; rcu_read_lock(); - xas_for_each(&xas, page, ULONG_MAX) { - if (xas_retry(&xas, page)) - continue; - /* - * A shadow entry of a recently evicted page, a swap - * entry from shmem/tmpfs or a DAX entry. Return it - * without attempting to raise page count. - */ - if (xa_is_value(page)) - goto export; - - if (!page_cache_get_speculative(page)) - goto retry; - - /* Has the page moved or been split? */ - if (unlikely(page != xas_reload(&xas))) - goto put_page; - + while ((page = xas_find_get_entry(&xas, ULONG_MAX, XA_PRESENT))) { /* * Terminate early on finding a THP, to allow the caller to * handle it all at once; but continue if this is hugetlbfs. */ - if (PageTransHuge(page) && !PageHuge(page)) { + if (!xa_is_value(page) && PageTransHuge(page) && + !PageHuge(page)) { page = find_subpage(page, xas.xa_index); nr_entries = ret + 1; } -export: + indices[ret] = xas.xa_index; entries[ret] = page; if (++ret == nr_entries) break; - continue; -put_page: - put_page(page); -retry: - xas_reset(&xas); } rcu_read_unlock(); return ret; @@ -1871,30 +1887,16 @@ unsigned find_get_pages_range(struct address_space *mapping, pgoff_t *start, return 0; rcu_read_lock(); - xas_for_each(&xas, page, end) { - if (xas_retry(&xas, page)) - continue; + while ((page = xas_find_get_entry(&xas, end, XA_PRESENT))) { /* Skip over shadow, swap and DAX entries */ if (xa_is_value(page)) continue; - if (!page_cache_get_speculative(page)) - goto retry; - - /* Has the page moved or been split? */ - if (unlikely(page != xas_reload(&xas))) - goto put_page; - pages[ret] = find_subpage(page, xas.xa_index); if (++ret == nr_pages) { *start = xas.xa_index + 1; goto out; } - continue; -put_page: - put_page(page); -retry: - xas_reset(&xas); } /* @@ -1993,9 +1995,7 @@ unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index, return 0; rcu_read_lock(); - xas_for_each_marked(&xas, page, end, tag) { - if (xas_retry(&xas, page)) - continue; + while ((page = xas_find_get_entry(&xas, end, tag))) { /* * Shadow entries should never be tagged, but this iteration * is lockless so there is a window for page reclaim to evict @@ -2004,23 +2004,11 @@ unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index, if (xa_is_value(page)) continue; - if (!page_cache_get_speculative(page)) - goto retry; - - /* Has the page moved or been split? */ - if (unlikely(page != xas_reload(&xas))) - goto put_page; - pages[ret] = page; if (++ret == nr_pages) { *index = page->index + thp_nr_pages(page); goto out; } - continue; -put_page: - put_page(page); -retry: - xas_reset(&xas); } /* -- 2.28.0