[PATCH v3] powerpc/mm: Implemented default_hugepagesz verification for powerpc

From: Victor Aoqui
Date: Mon Jul 24 2017 - 19:52:21 EST


Implemented default hugepage size verification (default_hugepagesz=)
in order to allow allocation of defined number of pages (hugepages=)
only for supported hugepage sizes.

Signed-off-by: Victor Aoqui <victora@xxxxxxxxxxxxxxxxxx>
---
v2:

- Renamed default_hugepage_setup_sz function to hugetlb_default_size_setup;
- Added powerpc string to error message.

v3:

- Renamed hugetlb_default_size_setup() to hugepage_default_setup_sz();
- Implemented hugetlb_bad_default_size();
- Reimplemented hugepage_setup_sz() to just parse default_hugepagesz= and
check if it's a supported size;
- Added verification of default_hugepagesz= value on hugetlb_nrpages_setup()
before allocating hugepages.

arch/powerpc/mm/hugetlbpage.c | 15 +++++++++++++++
include/linux/hugetlb.h | 1 +
mm/hugetlb.c | 17 +++++++++++++++--
3 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index e1bf5ca..5990381 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -780,6 +780,21 @@ static int __init hugepage_setup_sz(char *str)
}
__setup("hugepagesz=", hugepage_setup_sz);

+static int __init hugepage_default_setup_sz(char *str)
+{
+ unsigned long long size;
+
+ size = memparse(str, &str);
+
+ if (add_huge_page_size(size) != 0) {
+ hugetlb_bad_default_size();
+ pr_err("Invalid ppc default huge page size specified(%llu)\n", size);
+ }
+
+ return 1;
+}
+__setup("default_hugepagesz=", hugepage_default_setup_sz);
+
struct kmem_cache *hugepte_cache;
static int __init hugetlbpage_init(void)
{
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 0ed8e41..2927200 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -361,6 +361,7 @@ int huge_add_to_page_cache(struct page *page, struct address_space *mapping,
int __init alloc_bootmem_huge_page(struct hstate *h);

void __init hugetlb_bad_size(void);
+void __init hugetlb_bad_default_size(void);
void __init hugetlb_add_hstate(unsigned order);
struct hstate *size_to_hstate(unsigned long size);

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index bc48ee7..3c24266 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -54,6 +54,7 @@
static unsigned long __initdata default_hstate_max_huge_pages;
static unsigned long __initdata default_hstate_size;
static bool __initdata parsed_valid_hugepagesz = true;
+static bool __initdata parsed_valid_default_hugepagesz = true;

/*
* Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
@@ -2804,6 +2805,12 @@ void __init hugetlb_bad_size(void)
parsed_valid_hugepagesz = false;
}

+/* Should be called on processing a default_hugepagesz=... option */
+void __init hugetlb_bad_default_size(void)
+{
+ parsed_valid_default_hugepagesz = false;
+}
+
void __init hugetlb_add_hstate(unsigned int order)
{
struct hstate *h;
@@ -2846,8 +2853,14 @@ static int __init hugetlb_nrpages_setup(char *s)
* !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
* so this hugepages= parameter goes to the "default hstate".
*/
- else if (!hugetlb_max_hstate)
- mhp = &default_hstate_max_huge_pages;
+ else if (!hugetlb_max_hstate) {
+ if (!parsed_valid_default_hugepagesz) {
+ pr_warn("hugepages = %s cannot be allocated for "
+ "unsupported default_hugepagesz, ignoring\n", s);
+ parsed_valid_default_hugepagesz = true;
+ } else
+ mhp = &default_hstate_max_huge_pages;
+ }
else
mhp = &parsed_hstate->max_huge_pages;

--
1.8.3.1