patch-2.1.58 linux/mm/vmscan.c

• Lines: 61
• Date: Sun Oct 12 10:13:19 1997
• Orig file: v2.1.57/linux/mm/vmscan.c
• Orig date: Wed Sep 24 20:05:48 1997

diff -u --recursive --new-file v2.1.57/linux/mm/vmscan.c linux/mm/vmscan.c
@@ -24,9 +24,6 @@
 #include <linux/smp_lock.h>
 #include <linux/slab.h>
 
-#include <asm/dma.h>
-#include <asm/system.h> /* for cli()/sti() */
-#include <asm/uaccess.h> /* for copy_to/from_user */
 #include <asm/bitops.h>
 #include <asm/pgtable.h>
 
@@ -418,6 +415,7 @@
        printk ("Starting kswapd v%.*s\n", i, s);
 }
 
+#define MAX_SWAP_FAIL 3
 /*
  * The background pageout daemon.
  * Started as a kernel thread from the init process.
@@ -445,6 +443,8 @@
 	init_swap_timer();
 	
 	while (1) {
+		int fail;
+
 		kswapd_awake = 0;
 		current->signal = 0;
 		run_task_queue(&tq_disk);
@@ -455,13 +455,27 @@
 		 * We now only swap out as many pages as needed.
 		 * When we are truly low on memory, we swap out
 		 * synchronously (WAIT == 1).  -- Rik.
+		 * If we've had too many consecutive failures,
+		 * go back to sleep to let other tasks run.
+		 */
+		for (fail = 0; fail++ < MAX_SWAP_FAIL;) {
+			int pages, wait;
+
+			pages = nr_free_pages;
+			if (nr_free_pages >= min_free_pages)
+				pages += atomic_read(&nr_async_pages);
+			if (pages >= free_pages_high)
+				break;
+			wait = (pages < free_pages_low);
+			if (try_to_free_page(GFP_KERNEL, 0, wait))
+				fail = 0;
+		}
+		/*
+		 * Report failure if we couldn't reach the minimum goal.
 		 */
-		while(nr_free_pages < min_free_pages)
-			try_to_free_page(GFP_KERNEL, 0, 1);
-		while((nr_free_pages + atomic_read(&nr_async_pages)) < free_pages_low)
-			try_to_free_page(GFP_KERNEL, 0, 1);
-		while((nr_free_pages + atomic_read(&nr_async_pages)) < free_pages_high)
-			try_to_free_page(GFP_KERNEL, 0, 0);
+		if (nr_free_pages < min_free_pages)
+			printk("kswapd: failed, got %d of %d\n",
+				nr_free_pages, min_free_pages);
 	}
 }