Hi Jaegeuk, Changman, > -----Original Message----- > From: Jaegeuk Kim [mailto:jaegeuk@xxxxxxxxxx] > Sent: Wednesday, February 04, 2015 4:11 AM > To: Changman Lee > Cc: Chao Yu; linux-fsdevel@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > Subject: Re: [f2fs-dev] [PATCH 5/5 v3] f2fs: introduce a batched trim > > Hi Changman, > > Good idea! > > Change log from v2: > o add sysfs to change the # of sections for trimming. Good idea! > > Change log from v1: > o add description > o change the # of batched segments suggested by Chao > o make consistent for # of batched segments > > This patch introduces a batched trimming feature, which submits split discard > commands. > > This is to avoid long latency due to huge trim commands. > If fstrim was triggered ranging from 0 to the end of device, we should lock > all the checkpoint-related mutexes, resulting in very long latency. > > Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx> > --- > Documentation/ABI/testing/sysfs-fs-f2fs | 6 ++++++ > Documentation/filesystems/f2fs.txt | 4 ++++ > fs/f2fs/f2fs.h | 7 +++++++ > fs/f2fs/segment.c | 18 +++++++++++++----- > fs/f2fs/super.c | 2 ++ > 5 files changed, 32 insertions(+), 5 deletions(-) > > diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs > b/Documentation/ABI/testing/sysfs-fs-f2fs > index 6f9157f..2c4cc42 100644 > --- a/Documentation/ABI/testing/sysfs-fs-f2fs > +++ b/Documentation/ABI/testing/sysfs-fs-f2fs > @@ -74,3 +74,9 @@ Date: March 2014 > Contact: "Jaegeuk Kim" <jaegeuk.kim@xxxxxxxxxxx> > Description: > Controls the memory footprint used by f2fs. > + > +What: /sys/fs/f2fs/<disk>/trim_sections > +Date: February 2015 > +Contact: "Jaegeuk Kim" <jaegeuk@xxxxxxxxxx> > +Description: > + Controls the trimming rate in batch mode. > diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt > index 6758aa3..dac11d7 100644 > --- a/Documentation/filesystems/f2fs.txt > +++ b/Documentation/filesystems/f2fs.txt > @@ -199,6 +199,10 @@ Files in /sys/fs/f2fs/<devname> > checkpoint is triggered, and issued during the > checkpoint. By default, it is disabled with 0. > > + trim_sections This parameter controls the number of sections > + to be trimmed out in batch mode when FITRIM > + conducts. 32 sections is set by default. > + > ipu_policy This parameter controls the policy of in-place > updates in f2fs. There are five policies: > 0x01: F2FS_IPU_FORCE, 0x02: F2FS_IPU_SSR, > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > index 964c240..6f57da1 100644 > --- a/fs/f2fs/f2fs.h > +++ b/fs/f2fs/f2fs.h > @@ -105,6 +105,10 @@ enum { > CP_DISCARD, > }; > > +#define DEF_BATCHED_TRIM_SECTIONS 32 > +#define BATCHED_TRIM_SEGMENTS(sbi) \ > + (SM_I(sbi)->trim_sections * (sbi)->segs_per_sec) > + > struct cp_control { > int reason; > __u64 trim_start; > @@ -448,6 +452,9 @@ struct f2fs_sm_info { > int nr_discards; /* # of discards in the list */ > int max_discards; /* max. discards to be issued */ > > + /* for batched trimming */ > + int trim_sections; /* # of sections to trim */ > + > struct list_head sit_entry_set; /* sit entry set list */ > > unsigned int ipu_policy; /* in-place-update policy */ > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > index 5ea57ec..c542f63 100644 > --- a/fs/f2fs/segment.c > +++ b/fs/f2fs/segment.c > @@ -1066,14 +1066,20 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range) > end_segno = (end >= MAX_BLKADDR(sbi)) ? MAIN_SEGS(sbi) - 1 : > GET_SEGNO(sbi, end); > cpc.reason = CP_DISCARD; > - cpc.trim_start = start_segno; > - cpc.trim_end = end_segno; > cpc.trim_minlen = range->minlen >> sbi->log_blocksize; > > /* do checkpoint to issue discard commands safely */ > - mutex_lock(&sbi->gc_mutex); > - write_checkpoint(sbi, &cpc); > - mutex_unlock(&sbi->gc_mutex); > + for (; start_segno <= end_segno; > + start_segno += BATCHED_TRIM_SEGMENTS(sbi)) { > + cpc.trim_start = start_segno; > + cpc.trim_end = min_t(unsigned int, > + start_segno + BATCHED_TRIM_SEGMENTS (sbi) - 1, Actually what I mean is that in each trim we try to align start segment to first segment of section as much as possible. How about using: cpc.trim_end = min_t(unsigned int, rounddown(start_segno + BATCHED_TRIM_SEGMENTS(sbi), (sbi)->segs_per_sec) - 1, end_segno); Thanks, > + end_segno); > + > + mutex_lock(&sbi->gc_mutex); > + write_checkpoint(sbi, &cpc); > + mutex_unlock(&sbi->gc_mutex); > + } > out: > range->len = cpc.trimmed << sbi->log_blocksize; > return 0; > @@ -2127,6 +2133,8 @@ int build_segment_manager(struct f2fs_sb_info *sbi) > sm_info->nr_discards = 0; > sm_info->max_discards = 0; > > + sm_info->trim_sections = DEF_BATCHED_TRIM_SECTIONS; > + > INIT_LIST_HEAD(&sm_info->sit_entry_set); > > if (test_opt(sbi, FLUSH_MERGE) && !f2fs_readonly(sbi->sb)) { > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c > index 1e92c2e..f2fe666 100644 > --- a/fs/f2fs/super.c > +++ b/fs/f2fs/super.c > @@ -195,6 +195,7 @@ F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_no_gc_sleep_time, > no_gc_sleep_time); > F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_idle, gc_idle); > F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, reclaim_segments, rec_prefree_segments); > F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, max_small_discards, max_discards); > +F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, batched_trim_sections, trim_sections); > F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, ipu_policy, ipu_policy); > F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_ipu_util, min_ipu_util); > F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_fsync_blocks, min_fsync_blocks); > @@ -210,6 +211,7 @@ static struct attribute *f2fs_attrs[] = { > ATTR_LIST(gc_idle), > ATTR_LIST(reclaim_segments), > ATTR_LIST(max_small_discards), > + ATTR_LIST(batched_trim_sections), > ATTR_LIST(ipu_policy), > ATTR_LIST(min_ipu_util), > ATTR_LIST(min_fsync_blocks), > -- > 2.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
