Messages in this thread | | | Date | Thu, 29 Nov 2012 19:38:26 +0900 | From | Yasuaki Ishimatsu <> | Subject | Re: [PATCH v2 0/5] Add movablecore_map boot option |
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Hi Tony,
2012/11/29 6:34, Luck, Tony wrote: >> 1. use firmware information >> According to ACPI spec 5.0, SRAT table has memory affinity structure >> and the structure has Hot Pluggable Filed. See "5.2.16.2 Memory >> Affinity Structure". If we use the information, we might be able to >> specify movable memory by firmware. For example, if Hot Pluggable >> Filed is enabled, Linux sets the memory as movable memory. >> >> 2. use boot option >> This is our proposal. New boot option can specify memory range to use >> as movable memory. > > Isn't this just moving the work to the user? To pick good values for the
Yes.
> movable areas, they need to know how the memory lines up across > node boundaries ... because they need to make sure to allow some > non-movable memory allocations on each node so that the kernel can > take advantage of node locality.
There is no problem. Linux has already two boot options, kernelcore= and movablecore=. So if we use them, non-movable memory is divided into each node evenly.
But there is no way to specify a node used as movable currently. So we proposed the new boot option.
> So the user would have to read at least the SRAT table, and perhaps > more, to figure out what to provide as arguments. >
> Since this is going to be used on a dynamic system where nodes might > be added an removed - the right values for these arguments might > change from one boot to the next. So even if the user gets them right > on day 1, a month later when a new node has been added, or a broken > node removed the values would be stale.
I don't think so. Even if we hot add/remove node, the memory range of each memory device is not changed. So we don't need to change the boot option.
Thanks, Yasuaki Ishimatsu
> > -Tony >
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