Re: [RFC 2/2] perf: Marker software event and ioctl

From: Christopher Covington
Date: Fri Sep 12 2014 - 10:00:19 EST


On 09/12/2014 08:57 AM, Pawel Moll wrote:
> On Fri, 2014-09-12 at 13:43 +0100, Christopher Covington wrote:
>> Just to ask the dumb questions in case the answers I've come up with are
>> wrong: What is PAGE_SIZE on an arm64 kernel?
>
> It's either 4 or 64k, depending on CONFIG_ARM64_64K_PAGES.
>
>> How does userspace know?
>>
> #include <unistd.h>
> #include <stdio.h>
>
> int main(void)
> {
> printf("%ld\n", sysconf(_SC_PAGESIZE));
> return 0;
> }

Oh excellent, that actually works. Based on a misreading of the glibc code I
thought it was hard-coded to 64K.

Thanks,
Christopher

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