Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1740710

Re: [PATCH] mm, swap: Make VMA based swap readahead configurable

Show all headers | View raw

On Wed, Sep 27, 2017 at 10:35:12AM +0200, Michal Hocko wrote:
> On Wed 27-09-17 17:04:32, Minchan Kim wrote:
> > On Wed, Sep 27, 2017 at 09:48:35AM +0200, Michal Hocko wrote:
> > > On Wed 27-09-17 14:04:01, Minchan Kim wrote:
> [...]
> > > > The problem is users have disabled swap readahead by echo 0 > /proc/sys/
> > > > vm/page-cluster are regressed by this new interface /sys/kernel/mm/swap/
> > > > vma_ra_max_order. Because for disabling readahead completely, they should
> > > > disable vma_ra_max_order as well as page-cluster from now on.
> > > > 
> > > > So, goal of new config to notice new feature to admins so they can be aware
> > > > of new konb vma_ra_max_order as well as page-cluster.
> > > > I canont think other better idea to preventing such regression.
> > > > 
> > > > http://lkml.kernel.org/r/%3C20170913014019.GB29422@bbox%3E
> > > 
> > > So, how are you going to configure this when you do not know whether
> > > zram will be used? In other words what should e.g. distribution set this
> > > to?
> > 
> > I have no idea. Unfortunately, it depends on them. If they want to use
> > zram as swap, they should fix the script. Surely, I don't like it.
> > Instead, I wanted that page-cluster zeroing disables both virtual/pysical
> > swap readahead not to break current userspace. However, Huang doesn't
> > liek it.
> > If you have better idea, please suggest.
> 
> I understand your frustration but config options are not there to bypass
> proper design decisions. Why cannot we unconditionally disable all the
> read ahead when zram is enabled?

It's not a zram specific issue. Every users who have disabled swap readahead
via page-cluster will be broken, too.

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Re: [PATCH] mm, swap: Make VMA based swap readahead configurable Minchan Kim <minchan@kernel.org> - 2017-09-27 07:10 +0200
  Re: [PATCH] mm, swap: Make VMA based swap readahead configurable Michal Hocko <mhocko@kernel.org> - 2017-09-27 09:50 +0200
    Re: [PATCH] mm, swap: Make VMA based swap readahead configurable Minchan Kim <minchan@kernel.org> - 2017-09-27 10:10 +0200
      Re: [PATCH] mm, swap: Make VMA based swap readahead configurable Michal Hocko <mhocko@kernel.org> - 2017-09-27 10:40 +0200
        Re: [PATCH] mm, swap: Make VMA based swap readahead configurable Minchan Kim <minchan@kernel.org> - 2017-09-27 15:20 +0200
          Re: [PATCH] mm, swap: Make VMA based swap readahead configurable Michal Hocko <mhocko@kernel.org> - 2017-09-27 15:30 +0200
            Re: [PATCH] mm, swap: Make VMA based swap readahead configurable Minchan Kim <minchan@kernel.org> - 2017-09-27 15:50 +0200
              Re: [PATCH] mm, swap: Make VMA based swap readahead configurable Michal Hocko <mhocko@kernel.org> - 2017-09-27 16:00 +0200
                Re: [PATCH] mm, swap: Make VMA based swap readahead configurable Minchan Kim <minchan@kernel.org> - 2017-09-27 16:20 +0200
                Re: [PATCH] mm, swap: Make VMA based swap readahead configurable Michal Hocko <mhocko@kernel.org> - 2017-09-27 16:20 +0200
                Re: [PATCH] mm, swap: Make VMA based swap readahead configurable "Huang\, Ying" <ying.huang@intel.com> - 2017-09-28 03:10 +0200
                Re: [PATCH] mm, swap: Make VMA based swap readahead configurable Michal Hocko <mhocko@kernel.org> - 2017-10-02 09:30 +0200
                Re: [PATCH] mm, swap: Make VMA based swap readahead configurable Dave Hansen <dave.hansen@intel.com> - 2017-10-02 22:50 +0200

csiph-web