The patch titled
Subject: mm/page_alloc.c: clean up check_for_memory()
has been removed from the -mm tree. Its filename was
mm-page_alloc-clean-up-check_for_memory.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Oscar Salvador <osalvador@xxxxxxx>
Subject: mm/page_alloc.c: clean up check_for_memory()
check_for_memory() looks a bit confusing. First of all, we have this:
if (N_MEMORY == N_NORMAL_MEMORY)
return;
Checking the ENUM declaration, looks like N_MEMORY canot be equal to
N_NORMAL_MEMORY.
I could not find where N_MEMORY is set to N_NORMAL_MEMORY, or the other
way around either, so unless I am missing something, this condition will
never evaluate to true. It makes sense to get rid of it.
Moving forward, the operations within the loop look a bit confusing as
well.
We set N_HIGH_MEMORY unconditionally, and then we set N_NORMAL_MEMORY in
case we have CONFIG_HIGHMEM (N_NORMAL_MEMORY != N_HIGH_MEMORY) and zone <=
ZONE_NORMAL. (N_HIGH_MEMORY falls back to N_NORMAL_MEMORY on
!CONFIG_HIGHMEM systems, and that is why we can just go ahead and set
N_HIGH_MEMORY unconditionally)
Although this works, it is a bit subtle.
I think that this could be easier to follow:
First, we should only set N_HIGH_MEMORY in case we have CONFIG_HIGHMEM.
And then we should set N_NORMAL_MEMORY in case zone <= ZONE_NORMAL,
without further checking whether we have CONFIG_HIGHMEM or not.
Link: http://lkml.kernel.org/r/20180828210158.4617-1-osalvador@xxxxxxxxxxxxxxxxxx
Signed-off-by: Oscar Salvador <osalvador@xxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Michael Hocko <mhocko@xxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Pavel Tatashin <pavel.tatashin@xxxxxxxxxxxxx
Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
--- a/mm/page_alloc.c~mm-page_alloc-clean-up-check_for_memory
+++ a/mm/page_alloc.c
@@ -6803,15 +6803,12 @@ static void check_for_memory(pg_data_t *
{
enum zone_type zone_type;
- if (N_MEMORY == N_NORMAL_MEMORY)
- return;
-
for (zone_type = 0; zone_type <= ZONE_MOVABLE - 1; zone_type++) {
struct zone *zone = &pgdat->node_zones[zone_type];
if (populated_zone(zone)) {
- node_set_state(nid, N_HIGH_MEMORY);
- if (N_NORMAL_MEMORY != N_HIGH_MEMORY &&
- zone_type <= ZONE_NORMAL)
+ if (IS_ENABLED(CONFIG_HIGHMEM))
+ node_set_state(nid, N_HIGH_MEMORY);
+ if (zone_type <= ZONE_NORMAL)
node_set_state(nid, N_NORMAL_MEMORY);
break;
}
_
Patches currently in -mm which might be from osalvador@xxxxxxx are
