Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH v3 3/7] mm/lru: replace pgdat lru_lock with lruvec lock
To:     Matthew Wilcox <willy@infradead.org>
Cc:     cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, akpm@linux-foundation.org,
        mgorman@techsingularity.net, tj@kernel.org, hughd@google.com,
        khlebnikov@yandex-team.ru, daniel.m.jordan@oracle.com,
        yang.shi@linux.alibaba.com, Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Roman Gushchin <guro@fb.com>,
        Shakeel Butt <shakeelb@google.com>,
        Chris Down <chris@chrisdown.name>,
        Thomas Gleixner <tglx@linutronix.de>,
        Vlastimil Babka <vbabka@suse.cz>, Qian Cai <cai@lca.pw>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= <jglisse@redhat.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        David Rientjes <rientjes@google.com>,
        "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
        swkhack <swkhack@gmail.com>,
        "Potyra, Stefan" <Stefan.Potyra@elektrobit.com>,
        Mike Rapoport <rppt@linux.vnet.ibm.com>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        Colin Ian King <colin.king@canonical.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
        Peng Fan <peng.fan@nxp.com>,
        Nikolay Borisov <nborisov@suse.com>,
        Ira Weiny <ira.weiny@intel.com>,
        Kirill Tkhai <ktkhai@virtuozzo.com>,
        Yafang Shao <laoar.shao@gmail.com>
References: <1573874106-23802-1-git-send-email-alex.shi@linux.alibaba.com>
 <1573874106-23802-4-git-send-email-alex.shi@linux.alibaba.com>
 <20191116043806.GD20752@bombadil.infradead.org>
 <0bfa9a03-b095-df83-9cfd-146da9aab89a@linux.alibaba.com>
 <20191118121451.GG20752@bombadil.infradead.org>
 <296c7202-930e-4027-2e92-b8c64a908d88@linux.alibaba.com>
 <20191118123452.GM20752@bombadil.infradead.org>
From:   Alex Shi <alex.shi@linux.alibaba.com>
Message-ID: <45d33a1f-07a2-c0f5-d715-ef3396b1e9c1@linux.alibaba.com>
Date:   Tue, 19 Nov 2019 18:14:26 +0800
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:60.0)
 Gecko/20100101 Thunderbird/60.9.1
MIME-Version: 1.0
In-Reply-To: <20191118123452.GM20752@bombadil.infradead.org>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


> 
>>>> As your concern for a 'new' caller, since __split_huge_page is a static helper here, no distub for anyothers.
>>> Even though it's static, there may be other callers within the same file.
>>> Or somebody may decide to make it non-static in the future.  I think it's
>>> actually clearer to keep the irqflags as a separate parameter.
>>>
>>
>> But it's no one else using this function now. and no one get disturb, right? It's non sense to consider a 'possibility' issue.
> 
> It is not nonsense to consider the complexity of the mm!  Your patch makes
> it harder to understand unnecessarily.  Please be considerate of the other
> programmers who must build on what you have created.
> 

I believe the 'flags' parameter are using __split_huge_page is just for irqsave/restore of lru_lock, so move it into lruvec should be reduce the parameter jumping in caller/callee.
But in another side, the flags opitimze isn't close related with lru_lock change, and better to be split out.
So thanks for your comments, I will remove this part for this patchset.

Thanks!
Alex