Messages in this thread | | | Date | Wed, 3 Jun 2020 07:28:53 -0700 | From | Andi Kleen <> | Subject | Re: [PATCH v4 2/4] mm/util.c: make vm_memory_committed() more accurate |
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> Its time cost is about 800 nanoseconds on a 2C/4T platform and > 2~3 microseconds on a 2S/36C/72T server in normal case, and in > worst case where vm_committed_as's spinlock is under severe > contention, it costs 30~40 microseconds for the 2S/36C/72T sever,
This will be likely 40-80us on larger systems, although the overhead is often non linear so it might get worse.
> which should be fine for its only two users: /proc/meminfo and > HyperV balloon driver's status trace per second.
There are some setups who do frequent sampling of /proc/meminfo in the background. Increased overhead could be a problem for them. But not proposing a change now. If someone complains have to revisit I guess, perhaps adding a rate limit of some sort.
-Andi
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