From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756561AbdKGLPR (ORCPT ); Tue, 7 Nov 2017 06:15:17 -0500 Received: from mailout4.samsung.com ([203.254.224.34]:49411 "EHLO mailout4.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754593AbdKGLPP (ORCPT ); Tue, 7 Nov 2017 06:15:15 -0500 DKIM-Filter: OpenDKIM Filter v2.11.0 mailout4.samsung.com 20171107111513epoutp04fb36edb3950b510beec834ee0a2f74fe~0yXzU8p6z2879928799epoutp04c X-AuditID: b6c32a48-905ff7000000103e-7e-5a0195c0df29 From: Fan Li To: "'Chao Yu'" , "'Chao Yu'" , "'Jaegeuk Kim'" Cc: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Subject: [f2fs-dev] [PATCH] f2fs: optimize the way of traversing free_nid_bitmap Date: Tue, 07 Nov 2017 19:14:24 +0800 Message-id: <002201d357b9$adf558a0$09e009e0$@samsung.com> MIME-version: 1.0 Content-type: text/plain; charset="Windows-1252" Content-transfer-encoding: 7bit X-Mailer: Microsoft Outlook 14.0 Content-language: en-us Thread-index: AdNXuZEM0cDKuwcQT9qrzu4oJcACDA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFmpkleLIzCtJLcpLzFFi42LZdljTVPfAVMYogx8L1SxOTz3LZPFk/Sxm i0uL3C0u75rDZjH18VpWB1aPliNvWT02repk89i94DOTx+dNcgEsUVw2Kak5mWWpRfp2CVwZ k3ZNZyqYz1sxY88NxgbGu1xdjJwcEgImEjv+vWHqYuTiEBLYwSjxdcMSNgjnO6PE7DmzmGGq bs7fAZXYzShxZf5pZgjnFaPEyk/bWECq2ATUJbbM7AaaxcEhIpAq8WaPOojJLOAhsetYKUiF sECQxP7LdxhBbBYBVYnls7exgpTwClhKnGnJAAnzCghK/Jh8D2wgs4CBxOtfS9ghbHmJzWve Qp2jILHj7GtGiLi4xKQHD8FqRAT0JG582sAKcpmEwBo2icY1v1khGlwkWne1QDULS7w6voUd wpaWeLZqIyOEvY5R4vMZC4jm7YwS8z5+ZIJIWANt/gV1BZ9Ex+G/7CBHSwjwSnS0CUGUeEg8 O/AAao6jxNctk8D2CgnESpxuvs46gVFuFpLfZiH5bRaS32Yh+WcBI8sqRrHUguLc9NRiowIT veLE3OLSvHS95PzcTYzghKHlsYPxwDmfQ4wCHIxKPLwzDjJECbEmlhVX5h5ilOBgVhLh3a4O FOJNSaysSi3Kjy8qzUktPsQozcGiJM5bt+1ahJBAemJJanZqakFqEUyWiYNTqoHxUPh8rsbI GzdOFgR4b9i+iuV2vlOJjHv5rlXRmR4Z2/7NcdxeyVvSar/4qpblv2nfeJXPHs+6m1vmUyNV P3eL2b6Ay3MDc+Yw2Leyyks2nQ9en/nmv/z/k44XeJ7ezWEtXKcj2XTwqOaHqHP+36c7S61d Kbv67yLNU+ZP1xz3Lne973lWwP69EktxRqKhFnNRcSIAuzbN0RQDAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrHLMWRmVeSWpSXmKPExsVy+t9jAd0DUxmjDBpuSlqcnnqWyeLJ+lnM FpcWuVtc3jWHzWLq47WsDqweLUfesnpsWtXJ5rF7wWcmj8+b5AJYorhsUlJzMstSi/TtErgy Ju2azlQwn7dixp4bjA2Md7m6GDk5JARMJG7O38HWxcjFISSwk1Hi9Ms77BDOK0aJmXdes4JU sQmoS2yZ2c0EYosIpEqsbV4A1MHBwSzgIbHrWClIWFggQGLi+j1gJSwCqhLLZ29jBSnhFbCU ONOSARLmFRCU+DH5HguIzSygJ/Hxz21GCFteYvOat8wQ9yhI7Dj7GiouLjHpwUN2iK16Ejc+ bWCdwMg/C8moWUhGzUIyahaS9gWMLKsYJVMLinPTc4uNCozyUsv1ihNzi0vz0vWS83M3MQJD edthrf4djI+XxB9iFOBgVOLhnXGQIUqINbGsuDL3EKMEB7OSCO92daAQb0piZVVqUX58UWlO avEhRmkOFiVxXv78Y5FCAumJJanZqakFqUUwWSYOTqkGRvGMVpkHT1ijd01UF+Rm01n+qMBf gFVDcPO39VELrKPEZ81avU968a7nz1rD/l+VLM2fa/XssuHPomdmxp4hu3nteCTvCx3xm+s3 X2jHx8n3X947qNnzLF7g7fqLb2d/ZdiQJla8cqfUKeaIqzeDpqZYX53AGuqv/fbR12dR8dN3 TNU1Y00rLVFiKc5INNRiLipOBAC49CPsYQIAAA== X-CMS-MailID: 20171107111512epcas2p2bb846cc19c3d8fa6f2858874183c446c X-Msg-Generator: CA CMS-TYPE: 102P X-CMS-RootMailID: 20171107111512epcas2p2bb846cc19c3d8fa6f2858874183c446c X-RootMTR: 20171107111512epcas2p2bb846cc19c3d8fa6f2858874183c446c References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We call scan_free_nid_bits only when there isn't many free nids left, it means that marked bits in free_nid_bitmap are supposed to be few, use find_next_bit_le is more efficient in such case. According to my tests, use find_next_bit_le instead of test_bit_le will cut down the traversal time to one third of its original. Signed-off-by: Fan li --- fs/f2fs/node.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c index fef5c68..d234c6e 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -1955,6 +1955,7 @@ static void scan_free_nid_bits(struct f2fs_sb_info *sbi) struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA); struct f2fs_journal *journal = curseg->journal; unsigned int i, idx; + nid_t nid; down_read(&nm_i->nat_tree_lock); @@ -1964,10 +1965,10 @@ static void scan_free_nid_bits(struct f2fs_sb_info *sbi) if (!nm_i->free_nid_count[i]) continue; for (idx = 0; idx < NAT_ENTRY_PER_BLOCK; idx++) { - nid_t nid; - - if (!test_bit_le(idx, nm_i->free_nid_bitmap[i])) - continue; + idx = find_next_bit_le(nm_i->free_nid_bitmap[i], + NAT_ENTRY_PER_BLOCK, idx); + if (idx >= NAT_ENTRY_PER_BLOCK) + break; nid = i * NAT_ENTRY_PER_BLOCK + idx; add_free_nid(sbi, nid, true); @@ -1980,7 +1981,6 @@ static void scan_free_nid_bits(struct f2fs_sb_info *sbi) down_read(&curseg->journal_rwsem); for (i = 0; i < nats_in_cursum(journal); i++) { block_t addr; - nid_t nid; addr = le32_to_cpu(nat_in_journal(journal, i).block_addr); nid = le32_to_cpu(nid_in_journal(journal, i)); -- 2.7.4