Messages in this thread Patch in this message |  | | Date | Tue, 17 Feb 2015 14:02:49 +0100 | From | Sebastian Andrzej Siewior <> | Subject | Re: 3.14.23-rt20 - x86, UV: raw_spinlock conversion |
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* Mike Galbraith | 2014-11-02 08:31:37 [+0100]:
>Shrug. Lots of hobbyists have a beast in their basement, right?
I can take this as is if you want.
>--- a/arch/x86/platform/uv/uv_time.c >+++ b/arch/x86/platform/uv/uv_time.c >@@ -300,13 +300,18 @@ static int uv_rtc_unset_timer(int cpu, i > static cycle_t uv_read_rtc(struct clocksource *cs) > { > unsigned long offset; >+ cycle_t cycles; > >+ migrate_disable(); > if (uv_get_min_hub_revision_id() == 1) > offset = 0; > else > offset = (uv_blade_processor_id() * L1_CACHE_BYTES) % PAGE_SIZE; > >- return (cycle_t)uv_read_local_mmr(UVH_RTC | offset); >+ cycles = (cycle_t)uv_read_local_mmr(UVH_RTC | offset); >+ migrate_enable(); >+ >+ return cycles; > }
but do you really want a migrate_disable() in here? The only problem I can imagine is that you switch CPUs between uv_blade_processor_id() and the actual read. I recommend preempt_disable() and sending this upstream as well since it is not limited to -RT.
Sebastian
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