Re: [f2fs-dev] [PATCH 10/10] f2fs: return fs_trim if there is no candidate

[Jaegeuk Kim]

On 02/23, Chao Yu wrote:
> Hi Jaegeuk,
> 
> On 2017/2/23 5:26, Jaegeuk Kim wrote:
...
> >>> +	__u64 trim_start = cpc->trim_start;
> >>
> >> bool has_candidate = false;
> >>
> >>> +
> >>> +	mutex_lock(&SIT_I(sbi)->sentry_lock);
> >>> +	for (; trim_start <= cpc->trim_end; trim_start++)
> >>> +		if (add_discard_addrs(sbi, cpc, true))
> >>> +			break;
> >>
> >> for (; cpc->trim_start <= cpc->trim_end; cpc->trim_start++)
> >> 	if (add_discard_addrs(sbi, cpc, true)) {
> >> 		has_candidate = true;
> >> 		break;
> >> 	}
> > 
> > Why do we need to do like this in which needs additional variable with multiple
> > assignment?
> 
> Because add_discard_addrs will check segment which cpc->trim_start points to,
> but if we do not increase cpc->trim_start in loop, we will always check one
> segment, right?

Yeah~ ;)

> 
> Thanks,
> 
> > 
> > Thanks,
> > 
> >>
> >> cpc->trim_start = trim_start;
> >>
> >>> +	mutex_unlock(&SIT_I(sbi)->sentry_lock);
> >>> +
> >>> +	return trim_start <= cpc->trim_end;
> >>
> >> return has_candidate;
> >>
> >> Thanks,
> >>
> >>> +}
> >>> +
> >>>  int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range)
> >>>  {
> >>>  	__u64 start = F2FS_BYTES_TO_BLK(range->start);
> >>> @@ -2251,7 +2269,7 @@ void flush_sit_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc)
> >>>  			/* add discard candidates */
> >>>  			if (cpc->reason != CP_DISCARD) {
> >>>  				cpc->trim_start = segno;
> >>> -				add_discard_addrs(sbi, cpc);
> >>> +				add_discard_addrs(sbi, cpc, false);
> >>>  			}
> >>>  
> >>>  			if (to_journal) {
> >>> @@ -2289,7 +2307,7 @@ void flush_sit_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc)
> >>>  		__u64 trim_start = cpc->trim_start;
> >>>  
> >>>  		for (; cpc->trim_start <= cpc->trim_end; cpc->trim_start++)
> >>> -			add_discard_addrs(sbi, cpc);
> >>> +			add_discard_addrs(sbi, cpc, false);
> >>>  
> >>>  		cpc->trim_start = trim_start;
> >>>  	}
> >>>
> >>
> >>
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> > 
> > .
> > 
> 
> 
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