On 2018/9/2 18:34, Sahitya Tummala wrote: > On Sun, Sep 02, 2018 at 04:52:40PM +0800, Chao Yu wrote: >> On 2018/8/31 17:39, Sahitya Tummala wrote: >>> When dev is busy, discard thread wake up timeout can be aligned with the >>> exact time that it needs to wait for dev to come out of busy. This helps >>> to avoid unnecessary periodic wakeups and thus save some power. >>> >>> Signed-off-by: Sahitya Tummala <[email protected]> >>> --- >>> fs/f2fs/segment.c | 8 +++++++- >>> 1 file changed, 7 insertions(+), 1 deletion(-) >>> >>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c >>> index 8bcbb50..df14030 100644 >>> --- a/fs/f2fs/segment.c >>> +++ b/fs/f2fs/segment.c >>> @@ -1379,6 +1379,8 @@ static int issue_discard_thread(void *data) >>> struct discard_policy dpolicy; >>> unsigned int wait_ms = DEF_MIN_DISCARD_ISSUE_TIME; >>> int issued; >>> + unsigned long interval = sbi->interval_time[REQ_TIME] * HZ; >>> + long delta; >>> >>> set_freezable(); >>> >>> @@ -1410,7 +1412,11 @@ static int issue_discard_thread(void *data) >>> __wait_all_discard_cmd(sbi, &dpolicy); >>> wait_ms = dpolicy.min_interval; >>> } else if (issued == -1){ >>> - wait_ms = dpolicy.mid_interval; >>> + delta = (sbi->last_time[REQ_TIME] + interval) - jiffies; >> >> I agree that we need to consider power consumption. One more consideration is >> that discard thread may need different submission frequency comparing to >> garbage >> collection thread, maybe a little fast, would it be better to split >> sbi->interval_time[REQ_TIME] according to gc/discard type. >> >> How do you think? >> >> Thanks, >> > > Thanks for the review. > > You mean when GC type is urgent? I see that for that case, the discard policy > is
Actually, I mean splitting sbi->interval_time[REQ_TIME] into: - sbi->interval_time[GC_TIM] which can be used for GC thread. - sbi->interval_time[DISCARD_TIME] which can be used for Discard thread. Then we can configure sbi->interval_time[DISCARD_TIME] independently, and set more suitable interval value for discard thread, since discard thread may need to wake to submit discards more frequently. I guess if we can accept above idea, it can be sent as another patch, so anyway, I'm okay with your change. :) Reviewed-by: Chao Yu <[email protected]> Thanks, > changed to DPOLICY_FORCE, which sets dpolicy->io_aware as false and hence, > cannot fall into this (issued == -1) case at all. > >>> + if (delta > 0) >>> + wait_ms = jiffies_to_msecs(delta); >>> + else >>> + wait_ms = dpolicy.mid_interval; >>> } else { >>> wait_ms = dpolicy.max_interval; >>> } >>> > ------------------------------------------------------------------------------ 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 [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
