mm: Add min_free_order_shift tunable.
By default the kernel tries to keep half as much memory free at each
order as it does for one order below. This can be too agressive when
running without swap.
Change-Id: I5efc1a0b50f41ff3ac71e92d2efd175dedd54ead
Signed-off-by: Arve Hjønnevåg <arve@android.com>
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 9edcf45..1a07798 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -105,6 +105,7 @@
extern unsigned int core_pipe_limit;
#endif
extern int pid_max;
+extern int min_free_order_shift;
extern int pid_max_min, pid_max_max;
extern int percpu_pagelist_fraction;
extern int compat_log;
@@ -1266,6 +1267,13 @@
.extra1 = &zero,
},
{
+ .procname = "min_free_order_shift",
+ .data = &min_free_order_shift,
+ .maxlen = sizeof(min_free_order_shift),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec
+ },
+ {
.procname = "percpu_pagelist_fraction",
.data = &percpu_pagelist_fraction,
.maxlen = sizeof(percpu_pagelist_fraction),
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index c3edb62..58f55f6 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -197,6 +197,7 @@
};
int min_free_kbytes = 1024;
+int min_free_order_shift = 1;
static unsigned long __meminitdata nr_kernel_pages;
static unsigned long __meminitdata nr_all_pages;
@@ -1648,7 +1649,7 @@
free_pages -= z->free_area[o].nr_free << o;
/* Require fewer higher order pages to be free */
- min >>= 1;
+ min >>= min_free_order_shift;
if (free_pages <= min)
return false;