On Tue, 4 Nov 2014, Daniel J Blueman wrote:
> On 11/04/2014 03:38 AM, Thomas Gleixner wrote:
> > On Sun, 2 Nov 2014, Daniel J Blueman wrote:
> >
> > > On larger x64-64 systems, use a 2GB memory block size to reduce sysfs
> > > entry creation time by 16x. Large is defined as 64GB or more memory.
> >
> > This changelog sucks.
> >
> > It neither tells which sysfs entries are meant nor does it explain
> > what the actual effect of this change is aside of speeding up some
> > random sysfs thingy.
>
> How about this?
>
> On large-memory systems of 64GB or more with memory hot-plug enabled, use a
> 2GB memory block size. Eg with 64GB memory, this reduces the number of
> directories in /sys/devices/system/memory from 512 to 32, making it more
> manageable, and reducing the creation time accordingly.
It still does not tell what the downside is of this and why you think
it does not matter.
> > > @@ -1247,9 +1246,9 @@ static unsigned long probe_memory_block_size(void)
> > > /* start from 2g */
> > > unsigned long bz = 1UL<<31;
> > >
> > > -#ifdef CONFIG_X86_UV
> > > - if (is_uv_system()) {
> > > - printk(KERN_INFO "UV: memory block size 2GB\n");
> > > +#ifdef CONFIG_X86_64
> >
> > And this brainless 's/CONFIG_X86_UV/CONFIG_X86_64/' sucks even
> > more. I'm sure you can figure out the WHY yourself.
>
> The benefit of this is applicable to other architectures. I'm unable to test
> the change, but if you agree it's conservative enough, I'll drop the ifdef?
Which other architectures? Care to turn on your brain before replying?
Thanks,
tglx
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
