Fix a typo "end_pft" in the comment of walk_memory_range().
Signed-off-by: Toshi Kani <[email protected]>
---
mm/memory_hotplug.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index b81a367b..ae7bcba 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1613,7 +1613,7 @@ int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
/**
* walk_memory_range - walks through all mem sections in [start_pfn, end_pfn)
* @start_pfn: start pfn of the memory range
- * @end_pfn: end pft of the memory range
+ * @end_pfn: end pfn of the memory range
* @arg: argument passed to func
* @func: callback for each memory section walked
*
remove_memory() calls walk_memory_range() with [start_pfn, end_pfn),
where end_pfn is exclusive in this range. Therefore, end_pfn needs
to be set to the next page of the end address.
Signed-off-by: Toshi Kani <[email protected]>
---
mm/memory_hotplug.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index ae7bcba..3e2ab7b 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1801,7 +1801,7 @@ int __ref remove_memory(int nid, u64 start, u64 size)
int retry = 1;
start_pfn = PFN_DOWN(start);
- end_pfn = start_pfn + PFN_DOWN(size);
+ end_pfn = PFN_UP(start + size - 1);
/*
* When CONFIG_MEMCG is on, one memory block may be used by other
On Fri, 8 Mar 2013 08:41:41 -0700 Toshi Kani <[email protected]> wrote:
> remove_memory() calls walk_memory_range() with [start_pfn, end_pfn),
> where end_pfn is exclusive in this range. Therefore, end_pfn needs
> to be set to the next page of the end address.
>
> ...
>
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1801,7 +1801,7 @@ int __ref remove_memory(int nid, u64 start, u64 size)
> int retry = 1;
>
> start_pfn = PFN_DOWN(start);
> - end_pfn = start_pfn + PFN_DOWN(size);
> + end_pfn = PFN_UP(start + size - 1);
>
> /*
> * When CONFIG_MEMCG is on, one memory block may be used by other
That looks right, although these rounding/boundary things are always
hard. I wonder if `start' and `size' are ever not multiples of
PAGE_SIZE..
How did you discover this? Code inspection, or some runtime
malfunction? Please always include this info when fixing bugs.
On Fri, 2013-03-08 at 13:31 -0800, Andrew Morton wrote:
> On Fri, 8 Mar 2013 08:41:41 -0700 Toshi Kani <[email protected]> wrote:
>
> > remove_memory() calls walk_memory_range() with [start_pfn, end_pfn),
> > where end_pfn is exclusive in this range. Therefore, end_pfn needs
> > to be set to the next page of the end address.
> >
> > ...
> >
> > --- a/mm/memory_hotplug.c
> > +++ b/mm/memory_hotplug.c
> > @@ -1801,7 +1801,7 @@ int __ref remove_memory(int nid, u64 start, u64 size)
> > int retry = 1;
> >
> > start_pfn = PFN_DOWN(start);
> > - end_pfn = start_pfn + PFN_DOWN(size);
> > + end_pfn = PFN_UP(start + size - 1);
> >
> > /*
> > * When CONFIG_MEMCG is on, one memory block may be used by other
>
> That looks right, although these rounding/boundary things are always
> hard. I wonder if `start' and `size' are ever not multiples of
> PAGE_SIZE..
>
> How did you discover this? Code inspection, or some runtime
> malfunction? Please always include this info when fixing bugs.
It was found in code inspection. For ACPI memory hot-delete, both start
and size values are obtained from ACPI, and should always be
page-aligned. So, this issue is not exposed at this point. That said,
it should handle the boundary condition correctly since it might be
called from other path in future. Yes, I will include such info when
fixing bugs.
Thanks,
-Toshi