Mailing List Archive

From: Kong Wei <weikong@redflag-linux.com>

Unlimited of min_free_kbytes is dangerous,
An user of our company set this value bigger than 3584*1024*K,
cause the system OOM on DMA.
And I try a even more bigger number will cause the system hang immediately.
Limited as 64M may not a good value, but as default in init_per_zone_pages_min.
And this option may not need again?

Signed-off-by: Kong Wei <weikong@redflag-linux.com>
---
kernel/sysctl.c | 5 ++++-
mm/page_alloc.c | 2 +-
2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 8b7e954..d052522 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -103,6 +103,8 @@ static int minolduid;
static int min_percpu_pagelist_fract = 8;

static int ngroups_max = NGROUPS_MAX;
+static int min_min_free_kbytes = 128;
+static int max_min_free_kbytes = 65536;

#ifdef CONFIG_KMOD
extern char modprobe_path[];
@@ -1010,7 +1012,8 @@ static struct ctl_table vm_table[] = {
.mode = 0644,
.proc_handler = &min_free_kbytes_sysctl_handler,
.strategy = &sysctl_intvec,
- .extra1 = &zero,
+ .extra1 = &min_min_free_kbytes,
+ .extra2 = &max_min_free_kbytes,
},
{
.ctl_name = VM_PERCPU_PAGELIST_FRACTION,
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 75b9793..52979e9 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4179,7 +4179,7 @@ module_init(init_per_zone_pages_min)
int min_free_kbytes_sysctl_handler(ctl_table *table, int write,
struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
{
- proc_dointvec(table, write, file, buffer, length, ppos);
+ proc_dointvec_minmax(table, write, file, buffer, length, ppos);
if (write)
setup_per_zone_pages_min();
return 0;
--
1.5.0.3

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