Messages in this thread | | | Date | Tue, 4 Nov 2014 00:36:57 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [PATCH v3 5/5] Use 2GB memory block size on large x86-64 systems |
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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
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