Re: [PATCH] memory hotplug disable boot option
From: KAMEZAWA Hiroyuki
Date: Wed Jun 30 2010 - 23:49:17 EST
On Wed, 30 Jun 2010 22:17:35 -0500
Nathan Fontenot <nfont@xxxxxxxxxxxxxx> wrote:
> On 06/30/2010 07:31 PM, KAMEZAWA Hiroyuki wrote:
> > On Wed, 30 Jun 2010 08:47:55 -0700
> > Greg KH <gregkh@xxxxxxx> wrote:
> >>> and adding a scalable interface for large scale machines ?
> >>> I'd like to consider something..
> >> Dynamically changing the layout on big memory boxes makes sense to me,
> >> how about you?
> > like this ?
> > ==
> > boot option:
> > memory_sysfs_layout=compact
> > memory_sysfs_layout=auto (default)
> > memory_sysfs_layout=full
> > Considering briefly, how about this compact layout ?
> > /sys/devices/system/memory/:
> > list, hide, show, memoryX...
> > list: // show available memory index list.
> > #cat list
> > 0 1 2 ....10000...
> > show: //an interface to enable the interface.
> > #echo INDEX > memory_index
> > will create memoryINDEX diretory.
> > hide: //an interface to hide the interface.
> > #echo INDEX > memory_hide
> > will remove memoryINDEX sysfs directory.
> > In compact mode, all memoryX interface are hidden at boot.
> > In full mode, all memoryX interaface are shown.
> > The Boot option just affects status at boot. If users want, he can make
> > all memory sysfs in shown state.
> Do we need to make something as complicated as dynamically adding and removing
> the sysfs directories? Why not a compact layout that just takes the files
> that currently reside in the memoryXX dirs and move them up to the memory
> directory. This would be state (which should probably be split into an
> 'online' and 'offline' file), removable, phys_index, and phys_device.
I've considered several patterns.
with 4096 bytes buffer of sysfs, "printting bitmap" just covers small
amount of sections even with smart ASCII format to show contiguous range
as a chunk. That's my concern. (and 'list' file in above example
is impossible to impelement.)
If I can use rmdir/mkdir interface, it's much simple rather than above "echo".
But it seems impossible.
Because we have memory information in /proc/iomem already, I think hide/show
interface (instead of mkdir/rmdir) is not very bad.
If you can implement highly scalable interface, please.
I just stop dreaming and ack yours.
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