Re: [PATCH] kswapd: no need reclaim cma pages triggered by unmovable allocation

[zhou xianrong]

On 2021/2/10 下午9:14, Michal Hocko wrote:
> On Wed 10-02-21 12:07:57, zhou xianrong wrote:
> > On 2021/2/9 下午5:23, Michal Hocko wrote:
> > > On Tue 09-02-21 16:23:13, zhou wrote:
> > > > From: zhou xianrong <xianrong.zhou@xxxxxxxxxxxxx>
> > > >
> > > > For purpose of better migration cma pages are allocated after
> > > > failure movalbe allocations and are used normally for file pages
> > > > or anonymous pages.
> > > >
> > > > In reclaim path so many cma pages if configurated are reclaimed
> > > > from lru lists in kswapd mainly or direct reclaim triggered by
> > > > unmovable or reclaimable allocations. But these cma pages can not
> > > > be used by original unmovable or reclaimable allocations. So the
> > > > reclaim are unnecessary.
> > > >
> > > > In a same system if the cma pages were configurated to large then
> > > > more failture unmovable (vmalloc etc.) or reclaimable (slab etc.)
> > > > allocations are arised and then more kswapd rounds are triggered
> > > > and then more cma pages are reclaimed.
> > > Could you be more specific? Do you have any numbers and an example
> > > configuration when this is visible?
> > It should be implicit.
> Right but the scale of the problem is an important part of _any_ patch
> justification.
Sorry. The relative description is  not suitable and should be removed.