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? > > 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 <yuch...@huawei.com> > >>>>>>>> --- > >>>>>>>> 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 > >>>>>>> > >>>>>>> . > >>>>>>> > >>>>> > >>>>> . > >>>>> > >>> > >>> . > >>> > > > > . > > ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel