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From:   Florian Weimer <fw@deneb.enyo.de>
To:     Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc:     linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
        Michal Hocko <mhocko@suse.com>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Roman Gushchin <guro@fb.com>
Subject: Re: [PATCH RFC] fs/fcntl: add fcntl F_GET_RSS
References: <157225848971.557.16257813537984792761.stgit@buzz>
        <87k18p6qjk.fsf@mid.deneb.enyo.de>
        <d7e76bee-80c3-d787-b854-91e631ab29cd@yandex-team.ru>
Date:   Mon, 28 Oct 2019 14:05:52 +0100
In-Reply-To: <d7e76bee-80c3-d787-b854-91e631ab29cd@yandex-team.ru> (Konstantin
        Khlebnikov's message of "Mon, 28 Oct 2019 15:55:19 +0300")
Message-ID: <87ftjd6mvj.fsf@mid.deneb.enyo.de>
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* Konstantin Khlebnikov:

> On 28/10/2019 14.46, Florian Weimer wrote:
>> * Konstantin Khlebnikov:
>> 
>>> This implements fcntl() for getting amount of resident memory in cache.
>>> Kernel already maintains counter for each inode, this patch just exposes
>>> it into userspace. Returned size is in kilobytes like values in procfs.
>> 
>> I think this needs a 32-bit compat implementation which clamps the
>> returned value to INT_MAX.
>> 
>
> 32-bit machine couldn't hold more than 2TB cache in one file.
> Even radix tree wouldn't fit into low memory area.

I meant a 32-bit process running on a 64-bit kernel.