On 07/13/2010 07:35 PM, KAMEZAWA Hiroyuki wrote: > On Tue, 13 Jul 2010 10:51:58 -0500 > Nathan Fontenot <nf...@austin.ibm.com> wrote: > >>> >>> And for what purpose this interface is ? Does this split memory block into >>> 2 pieces >>> of the same size ?? sounds __very__ strange interface to me. >> >> Yes, this splits the memory_block into two blocks of the same size. This was >> suggested as something we may want to do. From ppc perspective I am not >> sure we >> would use this. >> >> The split functionality is not required. The main goal of the patch set is >> to >> reduce the number of memory sysfs directories created. From a ppc >> perspective >> the split functionality is not really needed. >> > > Okay, this is an offer from me. > > 1. I think you can add an boot option as "don't create memory sysfs". > please do.
I posted a patch to do that a week or so ago, it didn't go over very well. > > 2. I'd like to write a configfs module for handling memory hotplug even when > sysfs directroy is not created. > Because configfs support rmdir/mkdir, the user (ppc's daemon?) has to do > > When offlining section X. > # insmod configfs_memory.ko > # mount -t configfs none /configfs > # mkdir /configfs/memoryX > # echo offline > /configfs/memoryX/state > # rmdir /configfs/memoryX > > And making this operation as the default bahavior for all arch's memory > hotplug may > be better... > > Dave, how do you think ? Because ppc guys uses "probe" interface already, > this can be handled... no ? ppc would still require the existance of the 'probe' interface. Are you objecting to the 'split' functionality? If so I do not see any reason from ppc perspective that it is needed. This was something Dave suggested, unless I am missing something. Since ppc needs the 'probe' interface in sysfs, and for ppc having mutliple memory_block_sections reside under a single memory_block makes memory hotplug simpler. On ppc we do emory hotplug operations on an LMB size basis. With my patches this now lets us set each memory_block to span an LMB's worth of memory. Now we could do emory hotplug in a single operation instead of multiple operations to offline/online all of the memory sections in an LMB. Of course the easy solution would be to increase SECTION_SIZE_BITS, but we need support hardware that can have LMB's from 16 MB to 256 MB in size so the SECTION_SIZE_BITS value has to remain small. > > One problem is that I don't have enough knowledge about configfs..it seems > complex. Me neither, thoug I will take a look at it. -Nathan _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
