[PATCH] mm: page_alloc: simplify drain_zone_pages by using min()

[PATCH] mm: page_alloc: simplify drain_zone_pages by using min()

[Michal Nazarewicz]

Instead of open-coding getting minimal value of two, just use min macro.
That is why it is there for.  While changing the function also change
type of batch local variable to match type of per_cpu_pages::batch
(which is int).

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
---
 mm/page_alloc.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 5dba293..26aa003 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1224,15 +1224,11 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order,
 void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
 {
 	unsigned long flags;
-	int to_drain;
-	unsigned long batch;
+	int to_drain, batch;
 
 	local_irq_save(flags);
 	batch = ACCESS_ONCE(pcp->batch);
-	if (pcp->count >= batch)
-		to_drain = batch;
-	else
-		to_drain = pcp->count;
+	to_drain = min(pcp->count, batch);
 	if (to_drain > 0) {
 		free_pcppages_bulk(zone, to_drain, pcp);
 		pcp->count -= to_drain;
-- 
2.0.0.526.g5318336

Re: [PATCH] mm: page_alloc: simplify drain_zone_pages by using min()

[David Rientjes]

On Mon, 16 Jun 2014, Michal Nazarewicz wrote:

> Instead of open-coding getting minimal value of two, just use min macro.
> That is why it is there for.  While changing the function also change
> type of batch local variable to match type of per_cpu_pages::batch
> (which is int).
> 
> Signed-off-by: Michal Nazarewicz <mina86@mina86.com>

Acked-by: David Rientjes <rientjes@google.com>

Re: [PATCH] mm: page_alloc: simplify drain_zone_pages by using min()

[Andrew Morton]

On Mon, 16 Jun 2014 23:08:14 +0200 Michal Nazarewicz <mina86@mina86.com> wrote:

> Instead of open-coding getting minimal value of two, just use min macro.
> That is why it is there for.  While changing the function also change
> type of batch local variable to match type of per_cpu_pages::batch
> (which is int).
> 

I'm not sure why we made all the per_cpu_pages mambers `int'.  Unsigned
would make more sense.