Re: [PATCH 0/6] new zram statistics reporting scheme

From: Sergey Senozhatsky
Date: Wed Mar 11 2015 - 22:16:12 EST

On (03/12/15 10:55), Minchan Kim wrote:
> I really appreciate you enhance stat functions, esp, working with iostat!

thanks! my pleasure.

> One thing I want to discuss is sometime we could remove RO fields
> in /sys/block/zram/ but we couldn't remove RW fields because
> io_stat/mm_stat doesn't have any writable option now so users will
> have two options to read stat. For exmaple,

I played with CONFIG_ZRAM_OLD_STATS option, which turns RW attrs into
WO attrs (where possible/needed). but it turned out to be a rather
ugly patch and I eventually decided that I don't want to have these
#ifdef-s in zram code for the next two years. so providing both RW/RO
old stats (with a warning in the logs) and RO [mm|io]_stat sound like
a better plan.

> cat /sys/block/zram/mem_used_max
> cat /sys/block/zram/mm_stat | awk friend
> How about changing only writeable, not readable for duplicated stats
> in /sys/block/zram? So, user will have writeable stat to set some
> options in /sys/block/zram and readable stat to get some data in
> /sys/block/zram/[io|mm]_stat if the stat is duplicated in both.

Sorry, I probably didn't drink enough coffee today, can you please
rephrase or give a trivial example?

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