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| author | Eric Dumazet <edumazet@google.com> | 2018-03-23 14:58:17 -0700 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-03-27 12:01:47 +0200 |
| commit | 07cde313b2d21f728cec2836db7cdb55476f7a26 (patch) | |
| tree | 88e450ffab9354ddc069700898fb9d7d21c192b3 /crypto/tea.c | |
| parent | 13cc36d76bc4f5a9801ae32630bc8240ba0cc522 (diff) | |
| download | op-kernel-dev-07cde313b2d21f728cec2836db7cdb55476f7a26.zip op-kernel-dev-07cde313b2d21f728cec2836db7cdb55476f7a26.tar.gz | |
x86/msr: Allow rdmsr_safe_on_cpu() to schedule
High latencies can be observed caused by a daemon periodically reading
various MSR on all cpus. On KASAN enabled kernels ~10ms latencies can be
observed simply reading one MSR. Even without KASAN, sending an IPI to a
CPU, which is in a deep sleep state or in a long hard IRQ disabled section,
waiting for the answer can consume hundreds of microseconds.
All usage sites are in preemptible context, convert rdmsr_safe_on_cpu() to
use a completion instead of busy polling.
Overall daemon cpu usage was reduced by 35 %, and latencies caused by
msr_read() disappeared.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Link: https://lkml.kernel.org/r/20180323215818.127774-1-edumazet@google.com
Diffstat (limited to 'crypto/tea.c')
0 files changed, 0 insertions, 0 deletions
