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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 80002C77B76 for ; Sun, 16 Apr 2023 18:46:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229732AbjDPSqs (ORCPT ); Sun, 16 Apr 2023 14:46:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46826 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229808AbjDPSqr (ORCPT ); Sun, 16 Apr 2023 14:46:47 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C3DD5173D for ; Sun, 16 Apr 2023 11:46:45 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A5E4160F5A for ; Sun, 16 Apr 2023 18:46:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0BA36C433D2; Sun, 16 Apr 2023 18:46:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1681670805; bh=vBuSISLQXsEnivvRWeNy6TET42T2s5usBcDbW8AjVCM=; h=Date:To:From:Subject:From; b=kB7fTTGeo2ENAKQzlOyPBCmGdjB8HWYWLZnujN5E9ntc8QfZunnaZ+406XCAF97H1 W3uIBZ0MT5HHco7k1K9CpK4XERd334PhlwOQoqbtn+XJCurOK7a9BwxEPVcfEEa9Tl hxCtYzkNoQ81Ku24lp8/BVfYhfj2wWcwmgyw1nXM= Date: Sun, 16 Apr 2023 11:46:44 -0700 To: mm-commits@vger.kernel.org, zokeefe@google.com, yuzhao@google.com, willy@infradead.org, shy828301@gmail.com, ryan.roberts@arm.com, roman.gushchin@linux.dev, mkoutny@suse.com, kirill.shutemov@linux.intel.com, ziy@nvidia.com, akpm@linux-foundation.org From: Andrew Morton Subject: [to-be-updated] mm-truncate-split-huge-page-cache-page-to-a-non-zero-order-if-possible.patch removed from -mm tree Message-Id: <20230416184645.0BA36C433D2@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The quilt patch titled Subject: mm: truncate: split huge page cache page to a non-zero order if possible has been removed from the -mm tree. Its filename was mm-truncate-split-huge-page-cache-page-to-a-non-zero-order-if-possible.patch This patch was dropped because an updated version will be merged ------------------------------------------------------ From: Zi Yan Subject: mm: truncate: split huge page cache page to a non-zero order if possible Date: Mon, 3 Apr 2023 16:18:38 -0400 To minimize the number of pages after a huge page truncation, we do not need to split it all the way down to order-0. The huge page has at most three parts, the part before offset, the part to be truncated, the part remaining at the end. Find the greatest common divisor of them to calculate the new page order from it, so we can split the huge page to this order and keep the remaining pages as large and as few as possible. Link: https://lkml.kernel.org/r/20230403201839.4097845-7-zi.yan@sent.com Signed-off-by: Zi Yan Cc: Kirill A. Shutemov Cc: Matthew Wilcox (Oracle) Cc: Michal Koutný Cc: Roman Gushchin Cc: Ryan Roberts Cc: Yang Shi Cc: Yu Zhao Cc: Zach O'Keefe Signed-off-by: Andrew Morton --- mm/truncate.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) --- a/mm/truncate.c~mm-truncate-split-huge-page-cache-page-to-a-non-zero-order-if-possible +++ a/mm/truncate.c @@ -22,6 +22,7 @@ #include /* grr. try_to_release_page */ #include #include +#include #include "internal.h" /* @@ -211,7 +212,8 @@ int truncate_inode_folio(struct address_ bool truncate_inode_partial_folio(struct folio *folio, loff_t start, loff_t end) { loff_t pos = folio_pos(folio); - unsigned int offset, length; + unsigned int offset, length, remaining; + unsigned int new_order = folio_order(folio); if (pos < start) offset = start - pos; @@ -222,6 +224,7 @@ bool truncate_inode_partial_folio(struct length = length - offset; else length = end + 1 - pos - offset; + remaining = folio_size(folio) - offset - length; folio_wait_writeback(folio); if (length == folio_size(folio)) { @@ -236,11 +239,25 @@ bool truncate_inode_partial_folio(struct */ folio_zero_range(folio, offset, length); + /* + * Use the greatest common divisor of offset, length, and remaining + * as the smallest page size and compute the new order from it. So we + * can truncate a subpage as large as possible. Round up gcd to + * PAGE_SIZE, otherwise ilog2 can give -1 when gcd/PAGE_SIZE is 0. + */ + new_order = ilog2(round_up(gcd(gcd(offset, length), remaining), + PAGE_SIZE) / PAGE_SIZE); + + /* order-1 THP not supported, downgrade to order-0 */ + if (new_order == 1) + new_order = 0; + + if (folio_has_private(folio)) folio_invalidate(folio, offset, length); if (!folio_test_large(folio)) return true; - if (split_folio(folio) == 0) + if (split_huge_page_to_list_to_order(&folio->page, NULL, new_order) == 0) return true; if (folio_test_dirty(folio)) return false; _ Patches currently in -mm which might be from ziy@nvidia.com are mm-huge_memory-enable-debugfs-to-split-huge-pages-to-any-order.patch