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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED 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 7E221C3279B for ; Sat, 7 Jul 2018 00:08:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2E4A722485 for ; Sat, 7 Jul 2018 00:08:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="othWp1we" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2E4A722485 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754121AbeGGAIJ (ORCPT ); Fri, 6 Jul 2018 20:08:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:46304 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753713AbeGGAII (ORCPT ); Fri, 6 Jul 2018 20:08:08 -0400 Received: from [192.168.0.101] (unknown [49.77.239.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id BD6BD21A16; Sat, 7 Jul 2018 00:08:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1530922088; bh=SyjCEhlPykA2OGJjFFgRvV2PoPlJUhjcppwZXz16T4A=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=othWp1weZnteavu5QYs3hJZ68AftFZSgNVplq07iDniYikGWKanNW3V9yMGQoO7jA p/l/W3T6dVlXKT6EEJRFLLGn6XIMF37l+5AT6/TFqRIM556K+/LOwO1nMvEm9+Zuai Lp3doSOYbc0BZT54K3Hg1Lw4MeOq7z9eN44IlWz0= Subject: Re: [PATCH 2/2] f2fs: issue small discard by LBA order To: Jaegeuk Kim , Chao Yu Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org References: <20180705113701.3466-1-yuchao0@huawei.com> <20180705113701.3466-2-yuchao0@huawei.com> <20180706232345.GE77984@jaegeuk-macbookpro.roam.corp.google.com> From: Chao Yu Message-ID: <822c2d6b-1765-7956-2a30-09d0423e90a2@kernel.org> Date: Sat, 7 Jul 2018 08:08:03 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <20180706232345.GE77984@jaegeuk-macbookpro.roam.corp.google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jaegeuk, On 2018/7/7 7:23, Jaegeuk Kim wrote: > On 07/05, Chao Yu wrote: >> For small granularity discard which size is smaller than 64KB, if we >> issue those kind of discards orderly by size, their IOs will be spread >> into entire logical address, so that in FTL, L2P table will be updated >> randomly, result bad wear rate in the table. >> >> In this patch, we choose to issue small discard by LBA order, by this >> way, we can expect that L2P table updates from adjacent discard IOs can >> be merged in the cache, so it can reduce lifetime wearing of flash. >> >> Signed-off-by: Chao Yu >> --- >> fs/f2fs/f2fs.h | 2 ++ >> fs/f2fs/segment.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++ >> 2 files changed, 73 insertions(+) >> >> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h >> index 47ac0a9b022f..8d592029328a 100644 >> --- a/fs/f2fs/f2fs.h >> +++ b/fs/f2fs/f2fs.h >> @@ -290,6 +290,7 @@ struct discard_policy { >> unsigned int io_aware_gran; /* minimum granularity discard not be aware of I/O */ >> bool io_aware; /* issue discard in idle time */ >> bool sync; /* submit discard with REQ_SYNC flag */ >> + bool ordered; /* issue discard by lba order */ >> unsigned int granularity; /* discard granularity */ >> }; >> >> @@ -306,6 +307,7 @@ struct discard_cmd_control { >> unsigned int max_discards; /* max. discards to be issued */ >> unsigned int discard_granularity; /* discard granularity */ >> unsigned int undiscard_blks; /* # of undiscard blocks */ >> + unsigned int next_pos; /* next discard position */ >> atomic_t issued_discard; /* # of issued discard */ >> atomic_t issing_discard; /* # of issing discard */ >> atomic_t discard_cmd_cnt; /* # of cached cmd count */ >> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c >> index f95bf618bc1e..df0d91dfb8ac 100644 >> --- a/fs/f2fs/segment.c >> +++ b/fs/f2fs/segment.c >> @@ -18,6 +18,7 @@ >> #include >> #include >> #include >> +#include > > Why? I forgot to remove this... will do it. > >> >> #include "f2fs.h" >> #include "segment.h" >> @@ -936,6 +937,7 @@ static void __init_discard_policy(struct f2fs_sb_info *sbi, >> /* common policy */ >> dpolicy->type = discard_type; >> dpolicy->sync = true; >> + dpolicy->ordered = false; >> dpolicy->granularity = granularity; >> >> dpolicy->max_requests = DEF_MAX_DISCARD_REQUEST; >> @@ -947,6 +949,7 @@ static void __init_discard_policy(struct f2fs_sb_info *sbi, >> dpolicy->max_interval = DEF_MAX_DISCARD_ISSUE_TIME; >> dpolicy->io_aware = true; >> dpolicy->sync = false; >> + dpolicy->ordered = true; >> if (utilization(sbi) > DEF_DISCARD_URGENT_UTIL) { >> dpolicy->granularity = 1; >> dpolicy->max_interval = DEF_MIN_DISCARD_ISSUE_TIME; >> @@ -1202,6 +1205,69 @@ static int __queue_discard_cmd(struct f2fs_sb_info *sbi, >> return 0; >> } >> >> +static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi, >> + struct discard_policy *dpolicy) >> +{ >> + struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info; >> + struct discard_cmd *prev_dc = NULL, *next_dc = NULL; >> + struct rb_node **insert_p = NULL, *insert_parent = NULL; >> + struct discard_cmd *dc; >> + struct blk_plug plug; >> + unsigned int pos = dcc->next_pos; >> + unsigned int issued = 0, iter = 0; >> + bool io_interrupted; >> + >> + mutex_lock(&dcc->cmd_lock); >> + dc = (struct discard_cmd *)f2fs_lookup_rb_tree_ret(&dcc->root, >> + NULL, pos, >> + (struct rb_entry **)&prev_dc, >> + (struct rb_entry **)&next_dc, >> + &insert_p, &insert_parent, true); >> + if (!dc) >> + dc = next_dc; >> + >> + blk_start_plug(&plug); >> + >> + while (dc) { >> + struct rb_node *node; >> + >> + if (dc->state != D_PREP) >> + goto next; >> +retry: >> + io_interrupted = false; >> + >> + if (dpolicy->io_aware && !is_idle(sbi)) { >> + io_interrupted = true; >> + goto skip; > > Please don't try, if user is doing something. Just use 'break' instead of 'goto skip' here? > >> + } >> + >> + __submit_discard_cmd(sbi, dpolicy, dc); >> + issued++; >> + dcc->next_pos = dc->lstart + dc->len; >> +skip: >> + if (++iter >= dpolicy->max_requests) >> + break; >> + >> + if (io_interrupted) >> + goto retry; >> +next: >> + node = rb_next(&dc->rb_node); >> + dc = rb_entry_safe(node, struct discard_cmd, rb_node); >> + } >> + >> + blk_finish_plug(&plug); >> + >> + if (!dc) >> + dcc->next_pos = 0; >> + >> + mutex_unlock(&dcc->cmd_lock); >> + >> + if (!issued && io_interrupted) >> + issued = -1; >> + >> + return issued; >> +} >> + >> static int __issue_discard_cmd(struct f2fs_sb_info *sbi, >> struct discard_policy *dpolicy) >> { >> @@ -1215,6 +1281,10 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi, >> for (i = MAX_PLIST_NUM - 1; i >= 0; i--) { >> if (i + 1 < dpolicy->granularity) >> break; >> + >> + if (i < DEFAULT_DISCARD_GRANULARITY && dpolicy->ordered) >> + return __issue_discard_cmd_orderly(sbi, dpolicy); > > So, at this moment, we usually expect there'd be a bunch of small candidates > only, and thus, it'd be better to issue small chunks in LBA order? Yes, that's right. :) Thanks, > >> + >> pend_list = &dcc->pend_list[i]; >> >> mutex_lock(&dcc->cmd_lock); >> @@ -1786,6 +1856,7 @@ static int create_discard_cmd_control(struct f2fs_sb_info *sbi) >> dcc->nr_discards = 0; >> dcc->max_discards = MAIN_SEGS(sbi) << sbi->log_blocks_per_seg; >> dcc->undiscard_blks = 0; >> + dcc->next_pos = 0; >> dcc->root = RB_ROOT; >> dcc->rbtree_check = false; >> >> -- >> 2.18.0.rc1