From: sashiko-bot@kernel.org
To: "Luka Absandze" <absandze@amazon.de>
Cc: kvm@vger.kernel.org, linux-perf-users@vger.kernel.org
Subject: Re: [PATCH v2] KVM: x86/pmu: Don't retry a counter whose config was rejected
Date: Sun, 20 Sep 2026 16:00:31 +0000 [thread overview]
Message-ID: <20260920160031.D4A0D1F000FF@smtp.kernel.org> (raw)
In-Reply-To: <20260920155453.10836-1-absandze@amazon.de>
> kvm_pmu_handle_event() re-arms the reprogram bit for every failed
> reprogram, on the assumption that the failure is transient and a later
> refresh will succeed. That is true for contention, e.g. the -EBUSY from
> x86_reserve_hardware(), but not for a configuration the host PMU driver
> rejects outright. A rejected config can never succeed on retry, so the
> counter is reprogrammed on every PMU refresh for as long as the guest
> leaves it enabled, and every attempt fails the same way.
>
> Re-arm only for the errnos that indicate a transient condition, i.e.
> -EBUSY and -ENOMEM.
>
> Suggested-by: Sean Christopherson <seanjc@google.com>
> Link: https://lore.kernel.org/all/20260916123315.89042-1-absandze@amazon.de/
> Signed-off-by: Luka Absandze <absandze@amazon.de>
Sashiko has reviewed this patch and found no issues. It looks great!
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260920155453.10836-1-absandze@amazon.de?part=1
next prev parent reply other threads:[~2026-09-20 16:00 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-20 15:54 [PATCH v2] KVM: x86/pmu: Don't retry a counter whose config was rejected Luka Absandze
2026-09-20 16:00 ` sashiko-bot [this message]
2026-09-21 5:10 ` Sandipan Das
2026-09-21 5:11 ` Sandipan Das
2026-10-02 21:06 ` Sean Christopherson
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