Messages in this thread | | | Date | Fri, 25 Jun 2010 10:21:19 -0500 | From | Nathan Fontenot <> | Subject | Re: [PATCH] memory hotplug disable boot option |
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On 06/25/2010 09:56 AM, Andi Kleen wrote: > On Fri, Jun 25, 2010 at 09:51:37AM -0500, Nathan Fontenot wrote: >>> >>>>> Proposed patch to disable memory hotplug via a boot option, >>>>> mem_hotplug=[on|off]. The patch only disables memory hotplug in that it >>>>> prevents the creation of the memory sysfs directories for memory sections. >>>>> >>>>> This patch is meant to help alleviate very long boot times on systems with >>>>> large memory (1+ TB) and many memory sections (10's of thousands). >>>> >>>> Why making simple /sys file is so slowly? Couldn't we fix such performance >>>> problem? >> >> The issue is the large number of sysfs memory directories that get created. >> On a system with 1 TB of memory I am seeing ~63,00 directories. The long > > Maybe you could simply make the memory blocks larger on such large systems? > I agree 6k blocks are probably not very useful, but maybe 10 or 100 are? >
Yes, this would work to reduce the number of memory sections created. The reason I have not gone this route is that increasing the memory section size would break DLPAR memory add and remove for powerpc pseries.
-Nathan
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