patch-1.3.34 linux/include/linux/swapctl.h

• Lines: 115
• Date: Thu Oct 12 16:00:05 1995
• Orig file: v1.3.33/linux/include/linux/swapctl.h
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.33/linux/include/linux/swapctl.h linux/include/linux/swapctl.h
@@ -0,0 +1,114 @@
+#ifndef _LINUX_SWAPCTL_H
+#define _LINUX_SWAPCTL_H
+
+#include <asm/page.h>
+#include <linux/fs.h>
+
+/* Swap tuning control */
+
+/* First, enumerate the different reclaim policies */
+enum RCL_POLICY {RCL_ROUND_ROBIN, RCL_BUFF_FIRST, RCL_PERSIST};
+
+typedef struct swap_control_v5
+{
+	int	sc_max_page_age;
+	int	sc_page_advance;
+	int	sc_page_decline;
+	int	sc_page_initial_age;
+	int	sc_max_buff_age;
+	int	sc_buff_advance;
+	int	sc_buff_decline;
+	int	sc_buff_initial_age;
+	int	sc_age_cluster_fract;
+	int	sc_age_cluster_min;
+	int	sc_pageout_weight;
+	int	sc_bufferout_weight;
+	int 	sc_buffer_grace;
+	int 	sc_nr_buffs_to_free;
+	int 	sc_nr_pages_to_free;
+	enum RCL_POLICY	sc_policy;
+} swap_control_v5;
+
+typedef struct swap_control_v5 swap_control_t;
+
+extern swap_control_t swap_control;
+
+#define SC_VERSION	1
+#define SC_MAX_VERSION	1
+
+#ifdef __KERNEL__
+
+/* Define the maximum (least urgent) priority for the page reclaim code */
+#define RCL_MAXPRI 6
+/* We use an extra priority in the swap accounting code to represent
+   failure to free a resource at any priority */
+#define RCL_FAILURE (RCL_MAXPRI + 1)
+
+#define RCL_POLICY		(swap_control.sc_policy)
+#define AGE_CLUSTER_FRACT	(swap_control.sc_age_cluster_fract)
+#define AGE_CLUSTER_MIN		(swap_control.sc_age_cluster_min)
+#define PAGEOUT_WEIGHT		(swap_control.sc_pageout_weight)
+#define BUFFEROUT_WEIGHT	(swap_control.sc_bufferout_weight)
+
+#define NR_BUFFS_TO_FREE	(swap_control.sc_nr_buffs_to_free)
+#define NR_PAGES_TO_FREE	(swap_control.sc_nr_pages_to_free)
+
+#define BUFFERMEM_GRACE		(swap_control.sc_buffer_grace)
+
+/* Page aging (see mm/swap.c) */
+
+#define MAX_PAGE_AGE		(swap_control.sc_max_page_age)
+#define PAGE_ADVANCE		(swap_control.sc_page_advance)
+#define PAGE_DECLINE		(swap_control.sc_page_decline)
+#define PAGE_INITIAL_AGE	(swap_control.sc_page_initial_age)
+
+#define MAX_BUFF_AGE		(swap_control.sc_max_buff_age)
+#define BUFF_ADVANCE		(swap_control.sc_buff_advance)
+#define BUFF_DECLINE		(swap_control.sc_buff_decline)
+#define BUFF_INITIAL_AGE	(swap_control.sc_buff_initial_age)
+
+/* Given a resource of N units (pages or buffers etc), we only try to
+ * age and reclaim AGE_CLUSTER_FRACT per 1024 resources each time we
+ * scan the resource list. */
+static inline int AGE_CLUSTER_SIZE(int resources)
+{
+	int n = (resources * AGE_CLUSTER_FRACT) >> 10;
+	if (n < AGE_CLUSTER_MIN)
+		return AGE_CLUSTER_MIN;
+	else
+		return n;
+}
+
+static inline void touch_page(unsigned long addr)
+{
+	unsigned char age = mem_map[MAP_NR(addr)].age;
+	if (age < (MAX_PAGE_AGE - PAGE_ADVANCE))
+		age += PAGE_ADVANCE;
+	else
+		age = MAX_PAGE_AGE;
+	mem_map[MAP_NR(addr)].age = age;
+}
+
+static inline void age_page(unsigned long addr)
+{
+	unsigned char age = mem_map[MAP_NR(addr)].age;
+	if (age > PAGE_DECLINE)
+		age -= PAGE_DECLINE;
+	else
+		age = 0;
+	mem_map[MAP_NR(addr)].age = age;
+}
+
+static inline int age_of(unsigned long addr)
+{
+	return mem_map[MAP_NR(addr)].age;
+}
+
+static inline void set_page_new(unsigned long addr)
+{
+	mem_map[MAP_NR(addr)].age = PAGE_INITIAL_AGE;
+}
+
+#endif /* __KERNEL */
+
+#endif /* _LINUX_SWAPCTL_H */