Re: mm: shmem: freeing mlocked page

[Sasha Levin <sasha.levin@oracle.com>]

On 11/18/2014 10:56 PM, Andrew Morton wrote:
>> Trinity can't really log anything because attempts to log syscalls slow everything
>> > down to a crawl to the point nothing reproduces.
> Ah.  I was thinking that it could be worked out by looking at the
> trinity source around where it calls splice().  But I suspect that
> doesn't make sense if trinity just creates a zillion threads each of
> which sprays semi-random syscalls at the kernel(?).

I think Dave would agree here that this is a rather accurate description
of Trinity :)

>> > I've just looked at that trace above, and got a bit more confused. I didn't think
>> > that you can mlock page cache. How would a user do that exactly?
> mmap it then mlock it!  The kernel will fault everything in for you
> then pin it down.

But that's a pipe buffer, I didn't think userspace can mmap pipes? I have
some reading to do.


Thanks,
Sasha

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