[PATCH v2 4/7] mm, sysctl: make charging surplus hugepages controllable

[TSUKADA Koutaro]

Make the default hugetlb surplus hugepage controlable by
/proc/sys/vm/charge_surplus_hugepages.

Signed-off-by: TSUKADA Koutaro <tsuk...@ascade.co.jp>
---
 include/linux/hugetlb.h |    2 ++
 kernel/sysctl.c         |    7 +++++++
 mm/hugetlb.c            |   21 +++++++++++++++++++++
 3 files changed, 30 insertions(+)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 33fe5be..9314b07 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -80,6 +80,8 @@ struct hugepage_subpool *hugepage_new_subpool(struct hstate 
*h, long max_hpages,
 void reset_vma_resv_huge_pages(struct vm_area_struct *vma);
 int hugetlb_sysctl_handler(struct ctl_table *, int, void __user *, size_t *, 
loff_t *);
 int hugetlb_overcommit_handler(struct ctl_table *, int, void __user *, size_t 
*, loff_t *);
+int hugetlb_charge_surplus_handler(struct ctl_table *, int, void __user *,
+                                       size_t *, loff_t *);
 int hugetlb_treat_movable_handler(struct ctl_table *, int, void __user *, 
size_t *, loff_t *);

 #ifdef CONFIG_NUMA
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 6a78cf7..d562d64 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1394,6 +1394,13 @@ static int sysrq_sysctl_handler(struct ctl_table *table, 
int write,
                .mode           = 0644,
                .proc_handler   = hugetlb_overcommit_handler,
        },
+       {
+               .procname       = "charge_surplus_hugepages",
+               .data           = NULL,
+               .maxlen         = sizeof(int),
+               .mode           = 0644,
+               .proc_handler   = hugetlb_charge_surplus_handler,
+       },
 #endif
        {
                .procname       = "lowmem_reserve_ratio",
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 2e7b543..9a9549c 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3069,6 +3069,27 @@ int hugetlb_overcommit_handler(struct ctl_table *table, 
int write,
        return ret;
 }

+int hugetlb_charge_surplus_handler(struct ctl_table *table, int write,
+                       void __user *buffer, size_t *length, loff_t *ppos)
+{
+       struct hstate *h = &default_hstate;
+       int tmp, ret;
+
+       if (!hugepages_supported())
+               return -EOPNOTSUPP;
+
+       tmp = h->charge_surplus_huge_pages ? 1 : 0;
+       table->data = &tmp;
+       table->maxlen = sizeof(int);
+       ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
+       if (ret)
+               goto out;
+
+       if (write)
+               h->charge_surplus_huge_pages = tmp ? true : false;
+out:
+       return ret;
+}
 #endif /* CONFIG_SYSCTL */

 void hugetlb_report_meminfo(struct seq_file *m)

--
Tsukada