On Fri, 01 Oct 2010 13:37:49 -0500 Nathan Fontenot <nfont@xxxxxxxxxxxxxx> wrote: > Update the memory hotplug documentation to reflect the new behaviors of > memory blocks reflected in sysfs. > > Signed-off-by: Nathan Fontenot <nfont@xxxxxxxxxxxxxx> > Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Thank you for your patient work!. > --- > Documentation/memory-hotplug.txt | 47 +++++++++++++++++++++++++-------------- > 1 file changed, 31 insertions(+), 16 deletions(-) > > Index: linux-next/Documentation/memory-hotplug.txt > =================================================================== > --- linux-next.orig/Documentation/memory-hotplug.txt 2010-09-29 14:56:24.000000000 -0500 > +++ linux-next/Documentation/memory-hotplug.txt 2010-09-30 14:59:47.000000000 -0500 > @@ -126,36 +126,51 @@ > -------------------------------- > 4 sysfs files for memory hotplug > -------------------------------- > -All sections have their device information under /sys/devices/system/memory as > +All sections have their device information in sysfs. Each section is part of > +a memory block under /sys/devices/system/memory as > > /sys/devices/system/memory/memoryXXX > -(XXX is section id.) > +(XXX is the section id.) > > -Now, XXX is defined as start_address_of_section / section_size. > +Now, XXX is defined as (start_address_of_section / section_size) of the first > +section contained in the memory block. The files 'phys_index' and > +'end_phys_index' under each directory report the beginning and end section id's > +for the memory block covered by the sysfs directory. It is expected that all > +memory sections in this range are present and no memory holes exist in the > +range. Currently there is no way to determine if there is a memory hole, but > +the existence of one should not affect the hotplug capabilities of the memory > +block. > > For example, assume 1GiB section size. A device for a memory starting at > 0x100000000 is /sys/device/system/memory/memory4 > (0x100000000 / 1Gib = 4) > This device covers address range [0x100000000 ... 0x140000000) > > -Under each section, you can see 4 files. > +Under each section, you can see 4 or 5 files, the end_phys_index file being > +a recent addition and not present on older kernels. > > -/sys/devices/system/memory/memoryXXX/phys_index > +/sys/devices/system/memory/memoryXXX/start_phys_index > +/sys/devices/system/memory/memoryXXX/end_phys_index > /sys/devices/system/memory/memoryXXX/phys_device > /sys/devices/system/memory/memoryXXX/state > /sys/devices/system/memory/memoryXXX/removable > > -'phys_index' : read-only and contains section id, same as XXX. > -'state' : read-write > - at read: contains online/offline state of memory. > - at write: user can specify "online", "offline" command > -'phys_device': read-only: designed to show the name of physical memory device. > - This is not well implemented now. > -'removable' : read-only: contains an integer value indicating > - whether the memory section is removable or not > - removable. A value of 1 indicates that the memory > - section is removable and a value of 0 indicates that > - it is not removable. > +'phys_index' : read-only and contains section id of the first section > + in the memory block, same as XXX. > +'end_phys_index' : read-only and contains section id of the last section > + in the memory block. > +'state' : read-write > + at read: contains online/offline state of memory. > + at write: user can specify "online", "offline" command > + which will be performed on al sections in the block. > +'phys_device' : read-only: designed to show the name of physical memory > + device. This is not well implemented now. > +'removable' : read-only: contains an integer value indicating > + whether the memory block is removable or not > + removable. A value of 1 indicates that the memory > + block is removable and a value of 0 indicates that > + it is not removable. A memory block is removable only if > + every section in the block is removable. > > NOTE: > These directories/files appear after physical memory hotplug phase. > > > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>