From: Frederic Weisbecker <frederic@kernel.org>
To: Heiko Carstens <hca@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>,
Sven Schnelle <svens@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org
Subject: Re: [PATCH 2/9] s390/vtime: Fix virtual timer forwarding
Date: Wed, 4 Mar 2026 15:23:23 +0100 [thread overview]
Message-ID: <aahAWwMByLKmEvTu@localhost.localdomain> (raw)
In-Reply-To: <20260218142012.863464-3-hca@linux.ibm.com>
Le Wed, Feb 18, 2026 at 03:20:05PM +0100, Heiko Carstens a écrit :
> Since delayed accounting of system time [1] the virtual timer is
> forwarded by do_account_vtime() but also vtime_account_kernel(),
> vtime_account_softirq(), and vtime_account_hardirq(). This leads
> to double accounting of system, guest, softirq, and hardirq time.
>
> Remove accounting from the vtime_account*() family to restore old behavior.
>
> There is only one user of the vtimer interface, which might explain
> why nobody noticed this so far.
>
> Fixes: b7394a5f4ce9 ("sched/cputime, s390: Implement delayed accounting of system time") [1]
> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
--
Frederic Weisbecker
SUSE Labs
next prev parent reply other threads:[~2026-03-04 14:23 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-18 14:20 [PATCH 0/9] s390/idle/vtime: Minor fixes and cleanups Heiko Carstens
2026-02-18 14:20 ` [PATCH 1/9] s390/idle: Fix cpu idle exit cpu time accounting Heiko Carstens
2026-03-04 14:16 ` Frederic Weisbecker
2026-02-18 14:20 ` [PATCH 2/9] s390/vtime: Fix virtual timer forwarding Heiko Carstens
2026-03-04 14:23 ` Frederic Weisbecker [this message]
2026-02-18 14:20 ` [PATCH 3/9] s390/idle: Add comment for non obvious code Heiko Carstens
2026-03-04 14:38 ` Frederic Weisbecker
2026-02-18 14:20 ` [PATCH 4/9] s390/idle: Slightly optimize idle time accounting Heiko Carstens
2026-02-18 14:20 ` [PATCH 5/9] s390/idle: Inline update_timer_idle() Heiko Carstens
2026-03-04 15:07 ` Frederic Weisbecker
2026-02-18 14:20 ` [PATCH 6/9] s390/irq/idle: Remove psw bits early Heiko Carstens
2026-02-18 14:20 ` [PATCH 7/9] s390/vtime: Use __this_cpu_read() / get rid of READ_ONCE() Heiko Carstens
2026-03-04 14:49 ` Frederic Weisbecker
2026-02-18 14:20 ` [PATCH 8/9] s390/vtime: Use lockdep_assert_irqs_disabled() instead of BUG_ON() Heiko Carstens
2026-03-04 15:08 ` Frederic Weisbecker
2026-02-18 14:20 ` [PATCH 9/9] s390/idle: Remove psw_idle() prototype Heiko Carstens
2026-03-04 15:09 ` Frederic Weisbecker
2026-02-25 9:19 ` [PATCH 0/9] s390/idle/vtime: Minor fixes and cleanups Sven Schnelle
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