From: Thomas Gleixner <tglx@linutronix.de>
To: Frederic Weisbecker <frederic@kernel.org>,
Anna-Maria Behnsen <anna-maria@linutronix.de>
Cc: linux-kernel@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>
Subject: Re: [PATCH] timer: Preserve higher bits of expiration on index calculation
Date: Thu, 16 Jul 2020 16:24:19 +0200 [thread overview]
Message-ID: <87r1tbtu5o.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20200715221610.GC16227@lenoir>
Frederic Weisbecker <frederic@kernel.org> writes:
> Subject: [PATCH] timer: Preserve higher bits of expiration on index
> calculation
>
> The higher bits of the timer expiration are cropped while calling
> calc_index() due to the implicit cast from unsigned long to unsigned int.
>
> This loss shouldn't have consequences on the current code since all the
> computation to calculate the index is done on the lower 32 bits.
>
> However we are preparing to return the actual bucket expiration from
> calc_index() in order to properly fix base->next_expiry updates.
> Preserving the higher bits is a requirement to achieve that.
Nice catch!
prev parent reply other threads:[~2020-07-16 14:24 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-14 7:29 [PATCH v2] timers: Use only bucket expiry for base->next_expiry value Anna-Maria Behnsen
2020-07-15 12:40 ` Frederic Weisbecker
2020-07-15 22:16 ` [PATCH] timer: Preserve higher bits of expiration on index calculation Frederic Weisbecker
2020-07-16 14:24 ` Thomas Gleixner [this message]
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