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Date:   Thu, 2 Nov 2023 10:28:11 +0100
From:   Michal Hocko <mhocko@suse.com>
To:     "Huang, Ying" <ying.huang@intel.com>
Cc:     Johannes Weiner <hannes@cmpxchg.org>,
        Gregory Price <gourry.memverge@gmail.com>,
        linux-kernel@vger.kernel.org, linux-cxl@vger.kernel.org,
        linux-mm@kvack.org, akpm@linux-foundation.org,
        aneesh.kumar@linux.ibm.com, weixugc@google.com, apopple@nvidia.com,
        tim.c.chen@intel.com, dave.hansen@intel.com, shy828301@gmail.com,
        gregkh@linuxfoundation.org, rafael@kernel.org,
        Gregory Price <gregory.price@memverge.com>
Subject: Re: [RFC PATCH v3 0/4] Node Weights and Weighted Interleave
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On Thu 02-11-23 14:11:09, Huang, Ying wrote:
> Michal Hocko <mhocko@suse.com> writes:
> 
> > On Wed 01-11-23 10:21:47, Huang, Ying wrote:
> >> Michal Hocko <mhocko@suse.com> writes:
> > [...]
> >> > Well, I am not convinced about that TBH. Sure it is probably a good fit
> >> > for this specific CXL usecase but it just doesn't fit into many others I
> >> > can think of - e.g. proportional use of those tiers based on the
> >> > workload - you get what you pay for.
> >> 
> >> For "pay", per my understanding, we need some cgroup based
> >> per-memory-tier (or per-node) usage limit.  The following patchset is
> >> the first step for that.
> >> 
> >> https://lore.kernel.org/linux-mm/cover.1655242024.git.tim.c.chen@linux.intel.com/
> >
> > Why do we need a sysfs interface if there are plans for cgroup API?
> 
> They are for different target.  The cgroup API proposed here is to
> constrain the DRAM usage in a system with DRAM and CXL memory.  The less
> you pay, the less DRAM and more CXL memory you use.

Right, but why the usage distribution requires its own interface and
cannot be combined with the access control part of it?
-- 
Michal Hocko
SUSE Labs