Re: [PATCH -mm] mm: Fix memory hotplug + sparsemem build.

Yasunori Goto
2007-09-11T09:37:12Z

> > + if (onlined_pages){
>
> Nit, needs a space there before the '{'.

Ah, Ok. I attached fixed patch in this mail.

> The problem as I see it is that when we boot the system we start a
> kswapd on all nodes with memory. If the hot-add adds memory to a
> pre-existing node with no memory we will not start one and we end up
> with a node with memory and no kswapd. Bad.
>
> As kswapd_run is a no-op when a kswapd already exists this seems a safe
> way to fix that. Paul's ->zone conversion is obviously correct also.
>
> Acked-by: Andy Whitcroft <apw@shadowen.org>

Thanks for your explanation.
You mentioned all of my intention correctly. :-)

----

Fix kswapd doesn't run when memory is added on memory-less-node.
Fix compile error of zone->node when CONFIG_NUMA is off.

Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Andy Whitcroft <apw@shadowen.org>

---
mm/memory_hotplug.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

Index: current/mm/memory_hotplug.c
===================================================================
--- current.orig/mm/memory_hotplug.c 2007-09-07 18:08:07.000000000 +0900
+++ current/mm/memory_hotplug.c 2007-09-11 17:29:19.000000000 +0900
@@ -211,10 +211,12 @@ int online_pages(unsigned long pfn, unsi
online_pages_range);
zone->present_pages += onlined_pages;
zone->zone_pgdat->node_present_pages += onlined_pages;
- if (onlined_pages)
- node_set_state(zone->node, N_HIGH_MEMORY);

setup_per_zone_pages_min();
+ if (onlined_pages) {
+ kswapd_run(zone_to_nid(zone));
+ node_set_state(zone_to_nid(zone), N_HIGH_MEMORY);
+ }

if (need_zonelists_rebuild)
build_all_zonelists();
@@ -269,9 +271,6 @@ int add_memory(int nid, u64 start, u64 s
if (!pgdat)
return -ENOMEM;
new_pgdat = 1;
- ret = kswapd_run(nid);
- if (ret)
- goto error;
}

/* call arch's memory hotadd */

--
Yasunori Goto