Re: [REGRESSION] [BISECTED] kswapd high CPU usage

[Sergey Senozhatsky <sergey.senozhatsky@gmail.com>]

On (02/02/16 15:59), Kirill A. Shutemov wrote:
> > > On Sat, Jan 23, 2016 at 03:57:21PM +0000, Hugh Greenberg wrote:
> > > > Kirill A. Shutemov <kirill <at> shutemov.name> writes:
> > > > > 
> > > > > Could you try to insert 
> > "late_initcall(set_recommended_min_free_kbytes);"
> > > > > back and check if makes any difference.
> > > > > 
> > > > 
> > > > We tested adding late_initcall(set_recommended_min_free_kbytes); 
> > > > back in 4.1.14 and it made a huge difference. We aren't sure if the
> > > > issue is 100% fixed, but it could be. We will keep testing it.
> > > 
> > > It would be nice to have values of min_free_kbytes before and after
> > > set_recommended_min_free_kbytes() in your configuration.
> > > 
> > 
> > Before adding set_recommended_min_free_kbytes: 5391
> > After: 67584
> 
> [ add more people to the thread ]
> 
> The 'before' value look low to me for machine with 2G of RAM.
> 
> In the bugzilla[1], you've mentioned zram. I wounder if we need to
> increase min_free_kbytes when zram is in use as we do for THP.
> 
> [1] https://bugzilla.kernel.org/show_bug.cgi?id=110501

[add Seth Jennings]


additional info: http://marc.info/?l=linux-mm&m=145373987224270
> The reports are coming from 2GB Haswell chromebooks. I have a 4GB haswell
> chromebook and I cannot reproduce the issue, even if I boot the kernel with
> 2GB or less.
>
> After more testing, we were still able to reproduce the issue. It seems to
> have taken longer to show up this time.


a small note,
I assume, IF min_free_kbytes must be set then probably in zsmalloc (zbud?)
init, not in zram. zswap can use both -- zsmalloc and zbud.

	-ss

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