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Date:   Fri, 8 Nov 2019 10:31:36 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     tim <xiejingfeng@linux.alibaba.com>
Cc:     Johannes Weiner <hannes@cmpxchg.org>,
        Ingo Molnar <mingo@redhat.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] psi:fix divide by zero in psi_update_stats
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On Fri, Nov 08, 2019 at 03:33:24PM +0800, tim wrote:
> In psi_update_stats, it is possible that period has value like
> 0xXXXXXXXX00000000 where the lower 32 bit is 0, then it calls div_u64 which

How can this happen? Is that a valid case or should we be avoiding that?