Messages in this thread | | | Date | Thu, 10 Sep 2015 14:58:14 +0900 | From | Minchan Kim <> | Subject | Re: [PATCH v2] zram: introduce comp algorithm fallback functionality |
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On Thu, Sep 10, 2015 at 02:33:19PM +0900, Sergey Senozhatsky wrote: > Hello, > > On (09/10/15 14:03), Minchan Kim wrote: > [..] > > > > I guess most of scripts have checked result of his doing so if we > > removes it, it will break them. > > to be honest, we never documented or required any of those. the only source > of information for the user space -- zram.txt documentation -- simply says > to do 'echo 3 > /sys/block/zram0/max_comp_streams' or any other bunch of > 'echo'-s. so, technically, a user is free to simply copy-paste what we do > in zram.txt to his zram.sh and call it a "recommended way of doing things > in zram".
Agree. That's why we spend a lot discussion for this small change.
> > besides, zram.txt is outdated. for example there is no mem_used_max > documentation. > > we need to do better job documenting. I'll try to take a look on this later > this week.
Thanks.
> > > > Given that, every success of "echo zzz > /sys/block/zram0/comp_algorithm" > > makes users to be confused that he might think to success to change algorithm > > in runtime. IOW, it should return error which is more intuitive forme. > > well, not quite like that. we return -EINVAL on invalid output since > d93435c3fba4a47b773693b0c8992470d38510d5. this patch does not change > anything from this pov. it does, however, change the behaviour of > disksize store that follows.
I said like that you cut off.
"Although we could change ABI of optional parameters into no failure smoothly" ^^^^^^^^^^
> > I'm fine when the motivation for this patch is to introduce the > "fallback" mechanism (like zswap fallbacks to default compressor, f.e.), > but it wasn't the case -- I rewrote the patch slightly, reworded the > commit message and put some reasoning to this patch. > > -ss
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