Hi,
I am sending this e-mail once again because it probably
has been lost in abyss of Xen-devel/LKLM list.
Here is the second version of memory hotplug support
for Xen guests patch. This one cleanly applies to
git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git
repository, xen/memory-hotplug head.
Changes:
- /sys/devices/system/memory/probe interface has been removed;
/sys/devices/system/xen_memory/xen_memory0/{target,target_kb}
are much better (I forgot about them),
- most of the code have been moved to drivers/xen/balloon.c,
- this changes forced me to export hotadd_new_pgdat and
rollback_node_hotadd function from mm/memory_hotplug.c;
could it be accepted by mm/memory_hotplug.c maintainers ???
- PV on HVM mode is supported now; it was tested on
git://xenbits.xen.org/people/sstabellini/linux-pvhvm.git
repository, 2.6.34-pvhvm head,
- most of Jeremy suggestions have been applied.
On Wed, Jul 28, 2010 at 11:36:29AM +0400, Vasiliy G Tolstov wrote:
[...]
Work's fine with opensuse 11.3 (dom0 and domU)
Thx.
On Thu, Jul 29, 2010 at 12:39:52PM -0700, Jeremy Fitzhardinge wrote:
On 07/26/2010 05:41 PM, Daniel Kiper wrote:
Hi,
Currently there is fully working version.
It has been tested on Xen Ver. 4.0.0 in PV
guest i386/x86_64 with Linux kernel Ver. 2.6.32.16
and Ver. 2.6.34.1. This patch cleanly applys
to Ver. 2.6.34.1
Thanks. I've pushed this into xen.git as xen/memory-hotplug so people
can play with it more easily (but I haven't merged it into any of the
other branches yet).
Thx.
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+static inline unsigned long current_target(void)
+{
+ return balloon_stats.target_pages;
Why does this need its own version?
Because original version return values not bigger
then initial memory allocation which does not allow
memory hotplug to function.
+int __ref xen_add_memory(int nid, u64 start, u64 size)
+{
+ pg_data_t *pgdat = NULL;
+ int new_pgdat = 0, ret;
+
+ lock_system_sleep();
+
+ if (!node_online(nid)) {
+ pgdat = hotadd_new_pgdat(nid, start);
+ ret = -ENOMEM;
+ if (!pgdat)
+ goto out;
+ new_pgdat = 1;
+ }
+
+ /* call arch's memory hotadd */
+ ret = arch_add_memory(nid, start, size);
+
+ if (ret< 0)
+ goto error;
+
+ /* we online node here. we can't roll back from here. */
+ node_set_online(nid);
+
+ if (new_pgdat) {
+ ret = register_one_node(nid);
+ /*
+ * If sysfs file of new node can't create, cpu on the node
+ * can't be hot-added. There is no rollback way now.
+ * So, check by BUG_ON() to catch it reluctantly..
+ */
+ BUG_ON(ret);
+ }
This doesn't seem to be doing anything particularly xen-specific.
In general it could be generic however I do not know
it will be useful for others. If this function would
be accepted by mm/memory_hotplug.c maintainers we could
move it there. I removed from original add_memory funtion
resource allocation (and deallocation after error), which
must be done before XENMEM_populate_physmap in Xen. xen_add_memory
is called after physmap is fully populated.
If you have a questions please drop me a line.
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