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From:   Florian Weimer <fw@deneb.enyo.de>
To:     Minchan Kim <minchan@kernel.org>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Christian Brauner <christian.brauner@ubuntu.com>,
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        Michal Hocko <mhocko@suse.com>,
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        Linus Torvalds <torvalds@linux-foundation.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        Christian Brauner <christian@brauner.io>,
        Daniel Colascione <dancol@google.com>,
        Jens Axboe <axboe@kernel.dk>,
        Kirill Tkhai <ktkhai@virtuozzo.com>,
        SeongJae Park <sjpark@amazon.de>, linux-man@vger.kernel.org
Subject: Re: [PATCH v9 3/3] mm/madvise: introduce process_madvise() syscall: an external memory hinting API
References: <20200901000633.1920247-1-minchan@kernel.org>
        <20200901000633.1920247-4-minchan@kernel.org>
        <87blippc7p.fsf@mid.deneb.enyo.de>
        <20200903172618.GB1959033@google.com>
Date:   Thu, 03 Sep 2020 19:34:58 +0200
In-Reply-To: <20200903172618.GB1959033@google.com> (Minchan Kim's message of
        "Thu, 3 Sep 2020 10:26:18 -0700")
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* Minchan Kim:

> On Tue, Sep 01, 2020 at 08:46:02PM +0200, Florian Weimer wrote:
>> * Minchan Kim:
>> 
>> >       ssize_t process_madvise(int pidfd, const struct iovec *iovec,
>> >                 unsigned long vlen, int advice, unsigned int flags);
>> 
>> size_t for vlen provides a clearer hint regarding the type of special
>> treatment needed for ILP32 here (zero extension, not changing the type
>> to long long).
>> 
>
> All existing system calls using iove in Linux uses unsigned long so
> I want to be consistent with them unless process_madvise need something
> speicial.

Userspace uses int, following POSIX (where applicable).  There is no
consistency to be had here.