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From: "Huang, Ying" <ying.huang@intel.com>
To: Gregory Price <gregory.price@memverge.com>
Cc: Gregory Price <gourry.memverge@gmail.com>,  <linux-mm@kvack.org>,
  <linux-kernel@vger.kernel.org>,  <linux-doc@vger.kernel.org>,
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  <seungjun.ha@samsung.com>,  <hannes@cmpxchg.org>,
  <dan.j.williams@intel.com>,  Srinivasulu Thanneeru
 <sthanneeru.opensrc@micron.com>
Subject: Re: [PATCH v2 3/3] mm/mempolicy: introduce MPOL_WEIGHTED_INTERLEAVE
 for weighted interleaving
In-Reply-To: <Za9LnN59SBWwdFdW@memverge.com> (Gregory Price's message of "Tue,
	23 Jan 2024 00:16:12 -0500")
References: <20240119175730.15484-1-gregory.price@memverge.com>
	<20240119175730.15484-4-gregory.price@memverge.com>
	<87jzo0vjkk.fsf@yhuang6-desk2.ccr.corp.intel.com>
	<Za9GiqsZtcfKXc5m@memverge.com> <Za9LnN59SBWwdFdW@memverge.com>
Date: Tue, 23 Jan 2024 16:35:19 +0800
Message-ID: <87a5owv454.fsf@yhuang6-desk2.ccr.corp.intel.com>
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Gregory Price <gregory.price@memverge.com> writes:

> On Mon, Jan 22, 2024 at 11:54:34PM -0500, Gregory Price wrote:
>> > 
>> > Can the above code be simplified as something like below?
>> > 
>> >         resume_node = prev_node;
> ---         resume_weight = 0;
> +++         resume_weight = weights[node];
>> >         for (...) {
>> >                 ...
>> >         }
>> > 
>> 
>> I'll take another look at it, but this logic is annoying because of the
>> corner case:  me->il_prev can be NUMA_NO_NODE or an actual numa node.
>> 
>
> After a quick look, as long as no one objects to (me->il_prev) remaining
> NUMA_NO_NODE

MAX_NUMNODES-1 ?

> while having a weight assigned to pol->wil.cur_weight,

I think that it is OK.

And, IIUC, pol->wil.cur_weight can be 0, as in
weighted_interleave_nodes(), if it's 0, it will be assigned to default
weight for the node.

> then
> this looks like it can be simplified as above.
>
> I don't think it's harmful, but i'll have to take a quick look at what
> happens on rebind to make sure we don't have a stale weight.

Make sense.

--
Best Regards,
Huang, Ying