Re: [RFC PATCH 3/3] mm: increase scalability of global memory commitment accounting

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Wed, 10 Feb 2016 16:24:16 -0800 Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx> wrote:

> On Wed, 2016-02-10 at 13:28 -0800, Andrew Morton wrote:
> 
> > 
> > If a process is unmapping 4MB then it's pretty crazy for us to be
> > hitting the percpu_counter 32 separate times for that single operation.
> > 
> > Is there some way in which we can batch up the modifications within the
> > caller and update the counter less frequently?  Perhaps even in a
> > single hit?
> 
> I think the problem is the batch size is too small and we overflow
> the local counter into the global counter for 4M allocations.

That's one way of looking at the issue.  The other way (which I point
out above) is that we're calling vm_[un]_acct_memory too frequently
when mapping/unmapping 4M segments.

Exactly which mmap.c callsite is causing this issue?

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>



[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux]     [Linux OMAP]     [Linux MIPS]     [ECOS]     [Asterisk Internet PBX]     [Linux API]