From: Peter Zijlstra <peterz@infradead.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: akpm@linux-foundation.org, Ingo Molnar <mingo@redhat.com>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Johannes Weiner <hannes@cmpxchg.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] psi-pressure-stall-information-for-cpu-memory-and-io-fix-fix-fix
Date: Tue, 17 Jul 2018 17:17:58 +0200 [thread overview]
Message-ID: <20180717151758.GI2494@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20180717135133.3627980-1-arnd@arndb.de>
On Tue, Jul 17, 2018 at 03:51:24PM +0200, Arnd Bergmann wrote:
> The addition of do_div() did not do the right thing, as it assigned the
> result of the multiplication to an 'unsigned long', which truncates
> it before the division. GCC warns in various ways about this depending
> on the architecuture, e.g.
>
> arch/arm/include/asm/div64.h:33:45: note: expected 'uint64_t *' {aka 'long long unsigned int *'} but argument is of type 'long unsigned int *'
>
> This uses div_u64() instead. This is probably still a bad idea since
> we should avoid 64-bit division altogether in the scheduler, but at
> least it does the correct calculation.
>
> Fixes: 13a67bcb35f5 ("psi-pressure-stall-information-for-cpu-memory-and-io-fix-fix")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> Please fold into the fix
Please drop the entire PSI series instead.
prev parent reply other threads:[~2018-07-17 15:18 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-17 13:51 Arnd Bergmann
2018-07-17 15:17 ` Peter Zijlstra [this message]
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