This patch introduces two parameters cache_limit_ratio and cache_limit_mbytes.
They are used to limit page cache amount.
Signed-off-by: Xishi Qiu <qiuxishi@xxxxxxxxxx>
---
include/linux/swap.h | 10 ++++++++++
kernel/sysctl.c | 18 ++++++++++++++++++
mm/page_alloc.c | 39 +++++++++++++++++++++++++++++++++++++++
mm/vmscan.c | 17 +++++++++++++++++
4 files changed, 84 insertions(+), 0 deletions(-)
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 3507115..7e362d7 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -353,6 +353,16 @@ extern unsigned long shrink_all_memory(unsigned long nr_pages);
extern int vm_swappiness;
extern int remove_mapping(struct address_space *mapping, struct page *page);
extern unsigned long vm_total_pages;
+extern unsigned long vm_cache_limit_ratio;
+extern unsigned long vm_cache_limit_ratio_min;
+extern unsigned long vm_cache_limit_ratio_max;
+extern unsigned long vm_cache_limit_mbytes;
+extern unsigned long vm_cache_limit_mbytes_min;
+extern unsigned long vm_cache_limit_mbytes_max;
+extern int cache_limit_ratio_sysctl_handler(struct ctl_table *table, int write,
+ void __user *buffer, size_t *length, loff_t *ppos);
+extern int cache_limit_mbytes_sysctl_handler(struct ctl_table *table, int write,
+ void __user *buffer, size_t *length, loff_t *ppos);
#ifdef CONFIG_NUMA
extern int zone_reclaim_mode;
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 74f5b58..9bb6f38 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1272,6 +1272,24 @@ static struct ctl_table vm_table[] = {
.extra1 = &one,
.extra2 = &four,
},
+ {
+ .procname = "cache_limit_ratio",
+ .data = &vm_cache_limit_ratio,
+ .maxlen = sizeof(vm_cache_limit_ratio),
+ .mode = 0644,
+ .proc_handler = cache_limit_ratio_sysctl_handler,
+ .extra1 = &vm_cache_limit_ratio_min,
+ .extra2 = &vm_cache_limit_ratio_max,
+ },
+ {
+ .procname = "cache_limit_mbytes",
+ .data = &vm_cache_limit_mbytes,
+ .maxlen = sizeof(vm_cache_limit_mbytes),
+ .mode = 0644,
+ .proc_handler = cache_limit_mbytes_sysctl_handler,
+ .extra1 = &vm_cache_limit_mbytes_min,
+ .extra2 = &vm_cache_limit_mbytes_max,
+ },
#ifdef CONFIG_COMPACTION
{
.procname = "compact_memory",
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 5dba293..a9cc034 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5790,6 +5790,45 @@ int min_free_kbytes_sysctl_handler(ctl_table *table, int write,
return 0;
}
+int cache_limit_ratio_sysctl_handler(struct ctl_table *table, int write,
+ void __user *buffer, size_t *length, loff_t *ppos)
+{
+ int ret;
+
+ ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
+ if (ret)
+ return ret;
+ if (write) {
+ vm_cache_limit_mbytes = totalram_pages
+ * vm_cache_limit_ratio / 100
+ * PAGE_SIZE / (1024 * 1024UL);
+ if (vm_cache_limit_ratio)
+ printk(KERN_WARNING "cache limit set to %ld%\n",
+ vm_cache_limit_ratio);
+ }
+ return 0;
+}
+
+int cache_limit_mbytes_sysctl_handler(struct ctl_table *table, int write,
+ void __user *buffer, size_t *length, loff_t *ppos)
+{
+ int ret;
+
+ ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
+ if (ret)
+ return ret;
+ if (write) {
+ vm_cache_limit_ratio = (vm_cache_limit_mbytes
+ * ((1024 * 1024UL) / PAGE_SIZE)
+ + totalram_pages / 200)
+ * 100 / totalram_pages;
+ if (vm_cache_limit_mbytes)
+ printk(KERN_WARNING "cache limit set to %ldMB\n",
+ vm_cache_limit_mbytes);
+ }
+ return 0;
+}
+
#ifdef CONFIG_NUMA
int sysctl_min_unmapped_ratio_sysctl_handler(ctl_table *table, int write,
void __user *buffer, size_t *length, loff_t *ppos)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 32c661d..37ea902 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -131,6 +131,12 @@ struct scan_control {
*/
int vm_swappiness = 60;
unsigned long vm_total_pages; /* The total number of pages which the VM controls */
+unsigned long vm_cache_limit_ratio;
+unsigned long vm_cache_limit_ratio_min;
+unsigned long vm_cache_limit_ratio_max;
+unsigned long vm_cache_limit_mbytes __read_mostly;
+unsigned long vm_cache_limit_mbytes_min;
+unsigned long vm_cache_limit_mbytes_max;
static LIST_HEAD(shrinker_list);
static DECLARE_RWSEM(shrinker_rwsem);
@@ -3373,6 +3379,16 @@ unsigned long shrink_all_memory(unsigned long nr_to_reclaim)
}
#endif /* CONFIG_HIBERNATION */
+static void shrink_page_cache_init(void)
+{
+ vm_cache_limit_ratio = 0;
+ vm_cache_limit_ratio_min = 0;
+ vm_cache_limit_ratio_max = 100;
+ vm_cache_limit_mbytes = 0;
+ vm_cache_limit_mbytes_min = 0;
+ vm_cache_limit_mbytes_max = totalram_pages;
+}
+
/* It's optimal to keep kswapds on the same CPUs as their memory, but
not required for correctness. So if the last cpu in a node goes
away, we get changed to run anywhere: as the first one comes back,
@@ -3442,6 +3458,7 @@ static int __init kswapd_init(void)
for_each_node_state(nid, N_MEMORY)
kswapd_run(nid);
hotcpu_notifier(cpu_callback, 0);
+ shrink_page_cache_init();
return 0;
}
--
1.6.0.2
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