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[209.132.180.67]) by mx.google.com with ESMTP id y84-v6si22697538pfb.161.2018.08.14.20.31.33; Tue, 14 Aug 2018 20:31:48 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728602AbeHOGVB (ORCPT + 99 others); Wed, 15 Aug 2018 02:21:01 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:59508 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726003AbeHOGVB (ORCPT ); Wed, 15 Aug 2018 02:21:01 -0400 Received: from DGGEMS410-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 34D35D4E3D5AE; Wed, 15 Aug 2018 11:30:41 +0800 (CST) Received: from [127.0.0.1] (10.134.22.195) by DGGEMS410-HUB.china.huawei.com (10.3.19.210) with Microsoft SMTP Server id 14.3.399.0; Wed, 15 Aug 2018 11:30:41 +0800 Subject: Re: [PATCH 2/2] f2fs: tune discard speed with storage usage rate To: Jaegeuk Kim CC: , , References: <20180810100806.9298-1-yuchao0@huawei.com> <20180810100806.9298-2-yuchao0@huawei.com> <20180814041906.GC52730@jaegeuk-macbookpro.roam.corp.google.com> <57d9b6ea-68a5-4736-0b34-74db539d8959@huawei.com> <20180814172313.GC56510@jaegeuk-macbookpro.roam.corp.google.com> <20180815023326.GB84720@jaegeuk-macbookpro.roam.corp.google.com> <17aa1e09-6bfd-eb67-0f28-e13d8bbb17ff@huawei.com> <20180815025612.GC84720@jaegeuk-macbookpro.roam.corp.google.com> <03eec946-0cdb-7767-b5d9-9830072a3e71@huawei.com> <20180815032002.GE84720@jaegeuk-macbookpro.roam.corp.google.com> From: Chao Yu Message-ID: <73644ed5-7f66-3c03-c5ac-5b8b10b0e472@huawei.com> Date: Wed, 15 Aug 2018 11:30:40 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180815032002.GE84720@jaegeuk-macbookpro.roam.corp.google.com> Content-Type: text/plain; charset="windows-1252" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.134.22.195] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018/8/15 11:20, Jaegeuk Kim wrote: > On 08/15, Chao Yu wrote: >> On 2018/8/15 10:56, Jaegeuk Kim wrote: >>> On 08/15, Chao Yu wrote: >>>> On 2018/8/15 10:33, Jaegeuk Kim wrote: >>>>> On 08/15, Chao Yu wrote: >>>>>> On 2018/8/15 1:23, Jaegeuk Kim wrote: >>>>>>> On 08/14, Chao Yu wrote: >>>>>>>> On 2018/8/14 12:19, Jaegeuk Kim wrote: >>>>>>>>> On 08/10, Chao Yu wrote: >>>>>>>>>> Previously, discard speed was fixed mostly, and in high usage rate >>>>>>>>>> device, we will speed up issuing discard, but it doesn't make sense >>>>>>>>>> that in a non-full filesystem, we still issue discard with slow speed. >>>>>>>>> >>>>>>>>> Could you please elaborate the problem in more detail? The speed depends >>>>>>>>> on how many candidates? >>>>>>>> >>>>>>>> undiscard blocks are all 4k granularity. >>>>>>>> a) utility: filesystem: 20% + undiscard blocks: 20% = flash storage: 40% >>>>>>>> b) utility: filesystem: 40% + undiscard blocks: 25% = flash storage: 65% >>>>>>>> c) utility: filesystem: 60% + undiscard blocks: 30% = flash storage: 100% >>>>>>>> >>>>>>>> >>>>>>>> 1. for case c), we need to speed up issuing discard based on utilization of >>>>>>>> "filesystem + undiscard" instead of just utilization of filesystem. >>>>>>>> >>>>>>>> - if (utilization(sbi) > DEF_DISCARD_URGENT_UTIL) { >>>>>>>> - dpolicy->granularity = 1; >>>>>>>> - dpolicy->max_interval = DEF_MIN_DISCARD_ISSUE_TIME; >>>>>>>> - } >>>>>>>> >>>>>>>> 2. If free space in storage touches therein threshold, performance will be very >>>>>>>> sensitive. In low-end storage, with high usage in space, even free space is >>>>>>>> reduced by 1%, performance will decrease a lot. >>>>>>> >>>>>>> So, we may need to distinguish low-end vs. high-end storage. In high-end case, >>>>>>> it'd be better to avoid IO contention, while low-end device wants to get more >>>>>>> discard commands as much as possible. So, how about adding an option for this >>>>>>> as a tunable point? >>>>>> >>>>>> Agreed, how about adding a sysfs entry discard_tunning: >>>>>> 1: enabled, use 4k granularity, self-adapted speed based on real device free space. >>>>>> 0: disabled, use dcc->discard_granularity, fixed speed. >>>>>> >>>>>> By default: enabled >>>>>> >>>>>> How do you think? >>>>> >>>>> I don't think this is proper with a sysfs entry, since we already know the >>>> >>>> You mean by storage capacity? <= 32GB means low-end? >>> >>> Yes, that's current condition to judge it. If there is any other method, it'd be >> >> That would be hard code... >> >> Still I have not got any other method to do the judgment except capacity. > > Maybe ufs or emmc? Yeah, that's may be a good way. I remember very initial version UFS has very poor discard performance, for that kind of storage, it will be not accurate? Let me check whether there is a flag to distinguish ufs/emmc. Thanks, > >> >> Thanks, >> >>> better to change it. >>> >>>> >>>> Thanks, >>>> >>>>> device type when mounting the partition. We won't require to change the policy >>>>> on the fly. And, I still don't get to change the default. >>>>> >>>>>> >>>>>> Thanks, >>>>>> >>>>>>> >>>>>>>> >>>>>>>> IMO, in above cases, we'd better to issue discard with high speed for c), middle >>>>>>>> speed for b), and low speed for a). >>>>>>>> >>>>>>>> How do you think? >>>>>>>> >>>>>>>> Thanks, >>>>>>>> >>>>>>>>> >>>>>>>>> Thanks, >>>>>>>>> >>>>>>>>>> >>>>>>>>>> Anyway, it comes out undiscarded block makes FTL GC be lower efficient >>>>>>>>>> and causing high lifetime overhead. >>>>>>>>>> >>>>>>>>>> Let's tune discard speed as below: >>>>>>>>>> >>>>>>>>>> a. adjust default issue interval: >>>>>>>>>> original after >>>>>>>>>> min_interval: 50ms 100ms >>>>>>>>>> mid_interval: 500ms 1000ms >>>>>>>>>> max_interval: 60000ms 10000ms >>>>>>>>>> >>>>>>>>>> b. if last time we stop issuing discard due to IO interruption of user, >>>>>>>>>> let's reset all {min,mid,max}_interval to default one. >>>>>>>>>> >>>>>>>>>> c. tune {min,mid,max}_interval with below calculation method: >>>>>>>>>> >>>>>>>>>> base_interval = default_interval / 10; >>>>>>>>>> total_interval = default_interval - base_interval; >>>>>>>>>> interval = base_interval + total_interval * (100 - dev_util) / 100; >>>>>>>>>> >>>>>>>>>> For example: >>>>>>>>>> min_interval (:100ms) >>>>>>>>>> dev_util (%) interval (ms) >>>>>>>>>> 0 100 >>>>>>>>>> 10 91 >>>>>>>>>> 20 82 >>>>>>>>>> 30 73 >>>>>>>>>> ... >>>>>>>>>> 80 28 >>>>>>>>>> 90 19 >>>>>>>>>> 100 10 >>>>>>>>>> >>>>>>>>>> Signed-off-by: Chao Yu >>>>>>>>>> --- >>>>>>>>>> fs/f2fs/f2fs.h | 11 ++++---- >>>>>>>>>> fs/f2fs/segment.c | 64 +++++++++++++++++++++++++++++++++++++---------- >>>>>>>>>> fs/f2fs/segment.h | 9 +++++++ >>>>>>>>>> fs/f2fs/super.c | 2 +- >>>>>>>>>> 4 files changed, 67 insertions(+), 19 deletions(-) >>>>>>>>>> >>>>>>>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h >>>>>>>>>> index 273ffdaf4891..a1dd2e1c3cb9 100644 >>>>>>>>>> --- a/fs/f2fs/f2fs.h >>>>>>>>>> +++ b/fs/f2fs/f2fs.h >>>>>>>>>> @@ -185,10 +185,9 @@ enum { >>>>>>>>>> >>>>>>>>>> #define MAX_DISCARD_BLOCKS(sbi) BLKS_PER_SEC(sbi) >>>>>>>>>> #define DEF_MAX_DISCARD_REQUEST 8 /* issue 8 discards per round */ >>>>>>>>>> -#define DEF_MIN_DISCARD_ISSUE_TIME 50 /* 50 ms, if exists */ >>>>>>>>>> -#define DEF_MID_DISCARD_ISSUE_TIME 500 /* 500 ms, if device busy */ >>>>>>>>>> -#define DEF_MAX_DISCARD_ISSUE_TIME 60000 /* 60 s, if no candidates */ >>>>>>>>>> -#define DEF_DISCARD_URGENT_UTIL 80 /* do more discard over 80% */ >>>>>>>>>> +#define DEF_MIN_DISCARD_ISSUE_TIME 100 /* 100 ms, if exists */ >>>>>>>>>> +#define DEF_MID_DISCARD_ISSUE_TIME 1000 /* 1000 ms, if device busy */ >>>>>>>>>> +#define DEF_MAX_DISCARD_ISSUE_TIME 10000 /* 10000 ms, if no candidates */ >>>>>>>>>> #define DEF_CP_INTERVAL 60 /* 60 secs */ >>>>>>>>>> #define DEF_IDLE_INTERVAL 5 /* 5 secs */ >>>>>>>>>> >>>>>>>>>> @@ -248,7 +247,8 @@ struct discard_entry { >>>>>>>>>> }; >>>>>>>>>> >>>>>>>>>> /* default discard granularity of inner discard thread, unit: block count */ >>>>>>>>>> -#define DEFAULT_DISCARD_GRANULARITY 1 >>>>>>>>>> +#define MID_DISCARD_GRANULARITY 16 >>>>>>>>>> +#define MIN_DISCARD_GRANULARITY 1 >>>>>>>>>> >>>>>>>>>> /* max discard pend list number */ >>>>>>>>>> #define MAX_PLIST_NUM 512 >>>>>>>>>> @@ -330,6 +330,7 @@ struct discard_cmd_control { >>>>>>>>>> atomic_t discard_cmd_cnt; /* # of cached cmd count */ >>>>>>>>>> struct rb_root root; /* root of discard rb-tree */ >>>>>>>>>> bool rbtree_check; /* config for consistence check */ >>>>>>>>>> + bool io_interrupted; /* last state of io interrupted */ >>>>>>>>>> }; >>>>>>>>>> >>>>>>>>>> /* for the list of fsync inodes, used only during recovery */ >>>>>>>>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c >>>>>>>>>> index 8b52e8dfb12f..9564aaf1f27b 100644 >>>>>>>>>> --- a/fs/f2fs/segment.c >>>>>>>>>> +++ b/fs/f2fs/segment.c >>>>>>>>>> @@ -968,6 +968,44 @@ static void __check_sit_bitmap(struct f2fs_sb_info *sbi, >>>>>>>>>> #endif >>>>>>>>>> } >>>>>>>>>> >>>>>>>>>> +static void __adjust_discard_speed(unsigned int *interval, >>>>>>>>>> + unsigned int def_interval, int dev_util) >>>>>>>>>> +{ >>>>>>>>>> + unsigned int base_interval, total_interval; >>>>>>>>>> + >>>>>>>>>> + base_interval = def_interval / 10; >>>>>>>>>> + total_interval = def_interval - base_interval; >>>>>>>>>> + >>>>>>>>>> + /* >>>>>>>>>> + * if def_interval = 100, adjusted interval should be in range of >>>>>>>>>> + * [10, 100]. >>>>>>>>>> + */ >>>>>>>>>> + *interval = base_interval + total_interval * (100 - dev_util) / 100; >>>>>>>>>> +} >>>>>>>>>> + >>>>>>>>>> +static void __tune_discard_policy(struct f2fs_sb_info *sbi, >>>>>>>>>> + struct discard_policy *dpolicy) >>>>>>>>>> +{ >>>>>>>>>> + struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info; >>>>>>>>>> + int dev_util; >>>>>>>>>> + >>>>>>>>>> + if (dcc->io_interrupted) { >>>>>>>>>> + dpolicy->min_interval = DEF_MIN_DISCARD_ISSUE_TIME; >>>>>>>>>> + dpolicy->mid_interval = DEF_MID_DISCARD_ISSUE_TIME; >>>>>>>>>> + dpolicy->max_interval = DEF_MAX_DISCARD_ISSUE_TIME; >>>>>>>>>> + return; >>>>>>>>>> + } >>>>>>>>>> + >>>>>>>>>> + dev_util = dev_utilization(sbi); >>>>>>>>>> + >>>>>>>>>> + __adjust_discard_speed(&dpolicy->min_interval, >>>>>>>>>> + DEF_MIN_DISCARD_ISSUE_TIME, dev_util); >>>>>>>>>> + __adjust_discard_speed(&dpolicy->mid_interval, >>>>>>>>>> + DEF_MID_DISCARD_ISSUE_TIME, dev_util); >>>>>>>>>> + __adjust_discard_speed(&dpolicy->max_interval, >>>>>>>>>> + DEF_MAX_DISCARD_ISSUE_TIME, dev_util); >>>>>>>>>> +} >>>>>>>>>> + >>>>>>>>>> static void __init_discard_policy(struct f2fs_sb_info *sbi, >>>>>>>>>> struct discard_policy *dpolicy, >>>>>>>>>> int discard_type, unsigned int granularity) >>>>>>>>>> @@ -982,20 +1020,11 @@ static void __init_discard_policy(struct f2fs_sb_info *sbi, >>>>>>>>>> dpolicy->io_aware_gran = MAX_PLIST_NUM; >>>>>>>>>> >>>>>>>>>> if (discard_type == DPOLICY_BG) { >>>>>>>>>> - dpolicy->min_interval = DEF_MIN_DISCARD_ISSUE_TIME; >>>>>>>>>> - dpolicy->mid_interval = DEF_MID_DISCARD_ISSUE_TIME; >>>>>>>>>> - 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; >>>>>>>>>> - } >>>>>>>>>> + __tune_discard_policy(sbi, dpolicy); >>>>>>>>>> } else if (discard_type == DPOLICY_FORCE) { >>>>>>>>>> - dpolicy->min_interval = DEF_MIN_DISCARD_ISSUE_TIME; >>>>>>>>>> - dpolicy->mid_interval = DEF_MID_DISCARD_ISSUE_TIME; >>>>>>>>>> - dpolicy->max_interval = DEF_MAX_DISCARD_ISSUE_TIME; >>>>>>>>>> dpolicy->io_aware = false; >>>>>>>>>> } else if (discard_type == DPOLICY_FSTRIM) { >>>>>>>>>> dpolicy->io_aware = false; >>>>>>>>>> @@ -1353,6 +1382,8 @@ static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi, >>>>>>>>>> if (!issued && io_interrupted) >>>>>>>>>> issued = -1; >>>>>>>>>> >>>>>>>>>> + dcc->io_interrupted = io_interrupted; >>>>>>>>>> + >>>>>>>>>> return issued; >>>>>>>>>> } >>>>>>>>>> >>>>>>>>>> @@ -1370,7 +1401,7 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi, >>>>>>>>>> if (i + 1 < dpolicy->granularity) >>>>>>>>>> break; >>>>>>>>>> >>>>>>>>>> - if (i < DEFAULT_DISCARD_GRANULARITY && dpolicy->ordered) >>>>>>>>>> + if (i < MID_DISCARD_GRANULARITY && dpolicy->ordered) >>>>>>>>>> return __issue_discard_cmd_orderly(sbi, dpolicy); >>>>>>>>>> >>>>>>>>>> pend_list = &dcc->pend_list[i]; >>>>>>>>>> @@ -1407,6 +1438,8 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi, >>>>>>>>>> if (!issued && io_interrupted) >>>>>>>>>> issued = -1; >>>>>>>>>> >>>>>>>>>> + dcc->io_interrupted = io_interrupted; >>>>>>>>>> + >>>>>>>>>> return issued; >>>>>>>>>> } >>>>>>>>>> >>>>>>>>>> @@ -1576,7 +1609,11 @@ static int issue_discard_thread(void *data) >>>>>>>>>> struct f2fs_sb_info *sbi = data; >>>>>>>>>> struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info; >>>>>>>>>> wait_queue_head_t *q = &dcc->discard_wait_queue; >>>>>>>>>> - struct discard_policy dpolicy; >>>>>>>>>> + struct discard_policy dpolicy = { >>>>>>>>>> + .min_interval = DEF_MIN_DISCARD_ISSUE_TIME, >>>>>>>>>> + .mid_interval = DEF_MID_DISCARD_ISSUE_TIME, >>>>>>>>>> + .max_interval = DEF_MAX_DISCARD_ISSUE_TIME, >>>>>>>>>> + }; >>>>>>>>>> unsigned int wait_ms = DEF_MIN_DISCARD_ISSUE_TIME; >>>>>>>>>> int issued; >>>>>>>>>> >>>>>>>>>> @@ -1929,7 +1966,7 @@ static int create_discard_cmd_control(struct f2fs_sb_info *sbi) >>>>>>>>>> if (!dcc) >>>>>>>>>> return -ENOMEM; >>>>>>>>>> >>>>>>>>>> - dcc->discard_granularity = DEFAULT_DISCARD_GRANULARITY; >>>>>>>>>> + dcc->discard_granularity = MIN_DISCARD_GRANULARITY; >>>>>>>>>> INIT_LIST_HEAD(&dcc->entry_list); >>>>>>>>>> for (i = 0; i < MAX_PLIST_NUM; i++) >>>>>>>>>> INIT_LIST_HEAD(&dcc->pend_list[i]); >>>>>>>>>> @@ -1945,6 +1982,7 @@ static int create_discard_cmd_control(struct f2fs_sb_info *sbi) >>>>>>>>>> dcc->next_pos = 0; >>>>>>>>>> dcc->root = RB_ROOT; >>>>>>>>>> dcc->rbtree_check = false; >>>>>>>>>> + dcc->io_interrupted = false; >>>>>>>>>> >>>>>>>>>> init_waitqueue_head(&dcc->discard_wait_queue); >>>>>>>>>> SM_I(sbi)->dcc_info = dcc; >>>>>>>>>> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h >>>>>>>>>> index 422b0ceb1eaa..63b4da72cd34 100644 >>>>>>>>>> --- a/fs/f2fs/segment.h >>>>>>>>>> +++ b/fs/f2fs/segment.h >>>>>>>>>> @@ -616,6 +616,15 @@ static inline int utilization(struct f2fs_sb_info *sbi) >>>>>>>>>> sbi->user_block_count); >>>>>>>>>> } >>>>>>>>>> >>>>>>>>>> +static inline int dev_utilization(struct f2fs_sb_info *sbi) >>>>>>>>>> +{ >>>>>>>>>> + unsigned int dev_blks; >>>>>>>>>> + >>>>>>>>>> + dev_blks = valid_user_blocks(sbi) + SM_I(sbi)->dcc_info->undiscard_blks; >>>>>>>>>> + return div_u64((u64)dev_blks * 100, >>>>>>>>>> + MAIN_SEGS(sbi) << sbi->log_blocks_per_seg); >>>>>>>>>> +} >>>>>>>>>> + >>>>>>>>>> /* >>>>>>>>>> * Sometimes f2fs may be better to drop out-of-place update policy. >>>>>>>>>> * And, users can control the policy through sysfs entries. >>>>>>>>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c >>>>>>>>>> index b055f2ea77c5..55ed76daad23 100644 >>>>>>>>>> --- a/fs/f2fs/super.c >>>>>>>>>> +++ b/fs/f2fs/super.c >>>>>>>>>> @@ -2862,7 +2862,7 @@ static void f2fs_tuning_parameters(struct f2fs_sb_info *sbi) >>>>>>>>>> /* adjust parameters according to the volume size */ >>>>>>>>>> if (sm_i->main_segments <= SMALL_VOLUME_SEGMENTS) { >>>>>>>>>> F2FS_OPTION(sbi).alloc_mode = ALLOC_MODE_REUSE; >>>>>>>>>> - sm_i->dcc_info->discard_granularity = 1; >>>>>>>>>> + sm_i->dcc_info->discard_granularity = MIN_DISCARD_GRANULARITY; >>>>>>>>>> sm_i->ipu_policy = 1 << F2FS_IPU_FORCE; >>>>>>>>>> } >>>>>>>>>> >>>>>>>>>> -- >>>>>>>>>> 2.18.0.rc1 >>>>>>>>> >>>>>>>>> . >>>>>>>>> >>>>>>> >>>>>>> . >>>>>>> >>>>> >>>>> . >>>>> >>> >>> . >>> > > . >