[PATCH] Reap dead swap cache earlier v2

From: Marcelo Tosatti (marcelo@conectiva.com.br)
Date: Wed Jun 06 2001 - 15:07:41 EST


Hi,

As suggested by Linus, I've cleaned the reapswap code to be contained
inside an inline function. (yes, the if statement is really ugly)

Tested and against 2.4.6pre1.

--- linux.orig/mm/vmscan.c Wed Jun 6 18:16:45 2001
+++ linux/mm/vmscan.c Wed Jun 6 18:28:26 2001
@@ -407,6 +407,27 @@
         memory_pressure++;
         return page;
 }
+/*
+ * Check for dead swap cache pages and clean them, forcing
+ * those pages to be freed earlier.
+ */
+static inline int clean_dead_swap_page (struct page* page)
+{
+ int ret = 0;
+ if (!TryLockPage (page)) {
+ if (PageSwapCache(page) && PageDirty(page) &&
+ (page_count(page) - !!page->buffers) == 1 &&
+ swap_count(page) == 1) {
+ ClearPageDirty(page);
+ ClearPageReferenced(page);
+ page->age = 0;
+ ret = 1;
+ }
+ UnlockPage(page);
+ }
+ return ret;
+}
+
 
 /**
  * page_launder - clean dirty inactive pages, move to inactive_clean list
@@ -456,6 +477,12 @@
                         continue;
                 }
 
+ /*
+ * Check for dead swap cache pages
+ * before doing any other checks.
+ */
+ clean_dead_swap_page(page);
+
                 /* Page is or was in use? Move it to the active list. */
                 if (PageReferenced(page) || page->age > 0 ||
                                 page->zone->free_pages > page->zone->pages_high ||
@@ -666,6 +693,15 @@
                         printk("VM: refill_inactive, wrong page on list.\n");
                         list_del(page_lru);
                         nr_active_pages--;
+ continue;
+ }
+
+ /*
+ * Special case for dead swap cache pages.
+ */
+ if (clean_dead_swap_page(page)) {
+ deactivate_page_nolock(page);
+ nr_deactivated++;
                         continue;
                 }
 

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This archive was generated by hypermail 2b29 : Thu Jun 07 2001 - 21:00:54 EST