On 2019-5-21 8:10, Jaegeuk Kim wrote: > On 05/15, Chao Yu wrote: >> Hi Ju Hyung, >> >> On 2019/5/14 19:30, Ju Hyung Park wrote: >>> Hi Chao, >>> >>> On Tue, May 14, 2019 at 8:19 PM Chao Yu <[email protected]> wrote: >>>>> I've been using this(with a slightly different code) for years and yet to >>>>> notice >>>>> any spikes in lags/slowdowns. Worst scenario, I'd just have to deal with >>>>> an >>>>> added split second(100ms max?) delay in screen wake-up. >>>> >>>> I'm not sure about why this happened... maybe you need to do some test to >>>> analyse the root cause of it, filesystem/device fragment? too many >>>> undiscard >>>> space? or non-storage issue? >>> >>> Um, I'm not sure you understood what I said. >>> What I meant is that I haven't found any issues with using an approach >>> like this(gc_urgent with 1ms sleep intervals) for years on various >>> Android devices. >> >> Ah, sorry, I misread what you said. >> >>> >>>> I agreed that it should done as soon as possible, but it needs to consider >>>> IO >>>> race in between Apps after screen wake-up and BGGC to avoid potential ANR. >>> >>> I actually need to check whether vold turns off gc_urgent immediately >>> after screen turns itself back on. >>> I don't think we need to take potential ANR in to account *if* vold >>> stops gc_urgent right after screen-on. What do you think? >> >> What do you mean, I didn't catch it... >> >>> >>>> It's userspace strategy, we can change both of them >>>> (vold_wait_time/gc_urgent_sleep_time) in userspace if current value >>>> doesn't make >>>> any sense. >>> >>> Even the user can set the tunables themselves, the default should be >>> sensical imo. >> >> Agreed, how about adjusting this default value according device type, for >> fast >> device, like SSD, we can set default interval to very small value. >> >> Maybe we can implement this base on below commit if you agreed. >> >> f2fs: support tunning for multiple kind of storage device >> >> Thanks, >> >>> An "urgent" GC that only GCs up-to 2 segments per second doesn't sound >>> that "urgent" :p > > Yes, it seems I set it too conservatively at that time. It'd be fine to > decrease > the default time, but I'd prefer to remain the sysfs entry in order for user > to > configure it just in case. It'd be also great to have the above Chao's patch > to > have some default values regarding to discard/GC policies.
Cool, let me rework on that patch. :) Thanks, > > Thanks, > >>> >>> Thanks. >>> . >>> >> >> >> _______________________________________________ >> Linux-f2fs-devel mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel > > > _______________________________________________ > Linux-f2fs-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel > _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
