Re: [PATCH v5 00/11] mempolicy2, mbind2, and weighted interleave

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-doc@vger.kernel.org>,  <linux-fsdevel@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>,  <linux-api@vger.kernel.org>,
	<x86@kernel.org>,  <akpm@linux-foundation.org>,  <arnd@arndb.de>,
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	<bp@alien8.de>,  <dave.hansen@linux.intel.com>,  <hpa@zytor.com>,
	<mhocko@kernel.org>,  <tj@kernel.org>,  <corbet@lwn.net>,
	<rakie.kim@sk.com>,  <hyeongtak.ji@sk.com>,  <honggyu.kim@sk.com>,
	<vtavarespetr@micron.com>,  <peterz@infradead.org>,
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	<sthanneeru@micron.com>,  <emirakhur@micron.com>,
	 <Hasan.Maruf@amd.com>, <seungjun.ha@samsung.com>,
	 Johannes Weiner <hannes@cmpxchg.org>,
	 Hasan Al Maruf <hasanalmaruf@fb.com>,
	 Hao Wang <haowang3@fb.com>,
	 Dan Williams <dan.j.williams@intel.com>,
	 "Michal Hocko" <mhocko@suse.com>,
	 Zhongkun He <hezhongkun.hzk@bytedance.com>,
	 "Frank van der Linden" <fvdl@google.com>,
	 John Groves <john@jagalactic.com>,
	 Jonathan Cameron <Jonathan.Cameron@huawei.com>
Subject: Re: [PATCH v5 00/11] mempolicy2, mbind2, and weighted interleave
Date: Wed, 03 Jan 2024 11:15:06 +0800	[thread overview]
Message-ID: <87sf3fcdl1.fsf@yhuang6-desk2.ccr.corp.intel.com> (raw)
In-Reply-To: <ZZRepTEFNFC17fjT@memverge.com> (Gregory Price's message of "Tue, 2 Jan 2024 14:06:13 -0500")

Gregory Price <gregory.price@memverge.com> writes:

>> >> > struct mpol_args {
>> >> >         /* Basic mempolicy settings */
>> >> >         __u16 mode;
>> >> >         __u16 mode_flags;
>> >> >         __s32 home_node;
>> >> >         __u64 pol_maxnodes;
>> >> 
>> >> I understand that we want to avoid hole in struct.  But I still feel
>> >> uncomfortable to use __u64 for a small.  But I don't have solution too.
>> >> Anyone else has some idea?
>> >>
>> >
>> > maxnode has been an `unsigned long` in every other interface for quite
>> > some time.  Seems better to keep this consistent rather than it suddenly
>> > become `unsigned long` over here and `unsigned short` over there.
>> 
>> I don't think that it matters.  The actual maximum node number will be
>> less than maximum `unsigned short`.
>> 
>
> the structure will end up being
>
> struct mpol_args {
> 	__u16 mode;
> 	__u16 mode_flags;
> 	__s32 home_node;
> 	__u16 pol_maxnodes;
> 	__u8  rsv[6];
> 	__aligned_u64 pol_nodes;
> 	__aligned_u64 il_weights;
> }
>
> If you're fine with that, i'll make the change.

This looks OK for me.  But, I don't know whether others think this is
better.

--
Best Regards,
Huang, Ying