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,URIBL_BLOCKED autolearn=unavailable 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 4B155C433DB for ; Fri, 26 Feb 2021 01:16:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 17AF964F26 for ; Fri, 26 Feb 2021 01:16:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229508AbhBZBQb (ORCPT ); Thu, 25 Feb 2021 20:16:31 -0500 Received: from mail.kernel.org ([198.145.29.99]:48086 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229571AbhBZBQ2 (ORCPT ); Thu, 25 Feb 2021 20:16:28 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0780764EE4; Fri, 26 Feb 2021 01:15:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1614302146; bh=HLFVwss+VQySaWuX1zDyHVMMM6xebeYuJavtj5Pr4vY=; h=Date:From:To:Subject:In-Reply-To:From; b=q4mi66+LNzle8C4deJoPium9/ijLhtIak6FY0UKUvlb35h76OLR7vJEZQWAEERiHq HtrSUH/yqrcm4eArK2shW2mYQgDJzLXqAbCk2aX+w3dvmIdL4rYS8DoMVIoUl+PSt3 Qwu/gIpEKf9MimXX3ZLRdLM+ZPfjKfe79WEddc+M= Date: Thu, 25 Feb 2021 17:15:44 -0800 From: Andrew Morton To: akpm@linux-foundation.org, dchinner@redhat.com, hannes@cmpxchg.org, hch@lst.de, hughd@google.com, jack@suse.cz, kirill.shutemov@linux.intel.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org, william.kucharski@oracle.com, willy@infradead.org, yang.shi@linux.alibaba.com Subject: [patch 006/118] mm/filemap: add helper for finding pages Message-ID: <20210226011544.E1rCumDA1%akpm@linux-foundation.org> In-Reply-To: <20210225171452.713967e96554bb6a53e44a19@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/filemap: add helper for finding pages There is a lot of common code in find_get_entries(), find_get_pages_range() and find_get_pages_range_tag(). Factor out find_get_entry() which simplifies all three functions. [willy@infradead.org: remove VM_BUG_ON_PAGE()] Link: https://lkml.kernel.org/r/20201124041507.28996-2-willy@infradead.orgLink: https://lkml.kernel.org/r/20201112212641.27837-7-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Jan Kara Reviewed-by: William Kucharski Reviewed-by: Christoph Hellwig Cc: Dave Chinner Cc: Hugh Dickins Cc: Johannes Weiner Cc: Kirill A. Shutemov Cc: Yang Shi Signed-off-by: Andrew Morton --- mm/filemap.c | 97 +++++++++++++++++++++---------------------------- 1 file changed, 42 insertions(+), 55 deletions(-) --- a/mm/filemap.c~mm-filemap-add-helper-for-finding-pages +++ a/mm/filemap.c @@ -1825,6 +1825,42 @@ no_page: } EXPORT_SYMBOL(pagecache_get_page); +static inline struct page *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; + } + + return page; +reset: + xas_reset(xas); + goto retry; +} + /** * find_get_entries - gang pagecache lookup * @mapping: The address_space to search @@ -1864,42 +1900,21 @@ unsigned find_get_entries(struct address 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 = 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; @@ -1938,30 +1953,16 @@ unsigned find_get_pages_range(struct add return 0; rcu_read_lock(); - xas_for_each(&xas, page, end) { - if (xas_retry(&xas, page)) - continue; + while ((page = 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); } /* @@ -2061,9 +2062,7 @@ unsigned find_get_pages_range_tag(struct return 0; rcu_read_lock(); - xas_for_each_marked(&xas, page, end, tag) { - if (xas_retry(&xas, page)) - continue; + while ((page = 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 @@ -2072,23 +2071,11 @@ unsigned find_get_pages_range_tag(struct 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); } /* _