[patch 1/12] mm: free_pages_and_swap_cache opt

From: Nick Piggin
Date: Mon Nov 21 2005 - 08:23:56 EST

Minor optimization (though it doesn't help in the PREEMPT case, severely
constrained by small ZAP_BLOCK_SIZE). free_pages_and_swap_cache works in
chunks of 16, calling release_pages which works in chunks of PAGEVEC_SIZE.
But PAGEVEC_SIZE was dropped from 16 to 14 in 2.6.10, so we're now doing
more spin_lock_irq'ing than necessary: use PAGEVEC_SIZE throughout.

Signed-off-by: Hugh Dickins <hugh@xxxxxxxxxxx>

Index: linux-2.6/mm/swap_state.c
--- linux-2.6.orig/mm/swap_state.c
+++ linux-2.6/mm/swap_state.c
@@ -14,6 +14,7 @@
#include <linux/pagemap.h>
#include <linux/buffer_head.h>
#include <linux/backing-dev.h>
+#include <linux/pagevec.h>

#include <asm/pgtable.h>

@@ -272,12 +273,11 @@ void free_page_and_swap_cache(struct pag
void free_pages_and_swap_cache(struct page **pages, int nr)
- int chunk = 16;
struct page **pagep = pages;

while (nr) {
- int todo = min(chunk, nr);
+ int todo = min(nr, PAGEVEC_SIZE);
int i;

for (i = 0; i < todo; i++)
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