[PATCH 3/8] Allow huge page allocations to use GFP_HIGH_MOVABLE

From: Mel Gorman
Date: Thu Mar 01 2007 - 05:09:41 EST



Huge pages are not movable so are not allocated from ZONE_MOVABLE. However,
as ZONE_MOVABLE will always have pages that can be migrated or reclaimed,
it can be used to satisfy hugepage allocations even when the system has been
running a long time. This allows an administrator to resize the hugepage
pool at runtime depending on the size of ZONE_MOVABLE.

This patch adds a new sysctl called hugepages_treat_as_movable. When
a non-zero value is written to it, future allocations for the huge page
pool will use ZONE_MOVABLE. Despite huge pages being non-movable, we do not
introduce additional external fragmentation of note as huge pages are always
the largest contiguous block we care about.

Signed-off-by: Mel Gorman <mel@xxxxxxxxx>
---

include/linux/hugetlb.h | 3 +++
include/linux/mempolicy.h | 6 +++---
include/linux/sysctl.h | 1 +
kernel/sysctl.c | 8 ++++++++
mm/hugetlb.c | 23 ++++++++++++++++++++---
mm/mempolicy.c | 5 +++--
6 files changed, 38 insertions(+), 8 deletions(-)

diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.20-mm2-002_create_movable_zone/include/linux/hugetlb.h linux-2.6.20-mm2-003_mark_hugepages_movable/include/linux/hugetlb.h
--- linux-2.6.20-mm2-002_create_movable_zone/include/linux/hugetlb.h 2007-02-04 18:44:54.000000000 +0000
+++ linux-2.6.20-mm2-003_mark_hugepages_movable/include/linux/hugetlb.h 2007-02-19 09:13:13.000000000 +0000
@@ -14,6 +14,7 @@ static inline int is_vm_hugetlb_page(str
}

int hugetlb_sysctl_handler(struct ctl_table *, int, struct file *, void __user *, size_t *, loff_t *);
+int hugetlb_treat_movable_handler(struct ctl_table *, int, struct file *, void __user *, size_t *, loff_t *);
int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *, struct vm_area_struct *);
int follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *, struct page **, struct vm_area_struct **, unsigned long *, int *, int);
void unmap_hugepage_range(struct vm_area_struct *, unsigned long, unsigned long);
@@ -28,6 +29,8 @@ int hugetlb_reserve_pages(struct inode *
void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed);

extern unsigned long max_huge_pages;
+extern unsigned long hugepages_treat_as_movable;
+extern gfp_t htlb_alloc_mask;
extern const unsigned long hugetlb_zero, hugetlb_infinity;
extern int sysctl_hugetlb_shm_group;

diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.20-mm2-002_create_movable_zone/include/linux/mempolicy.h linux-2.6.20-mm2-003_mark_hugepages_movable/include/linux/mempolicy.h
--- linux-2.6.20-mm2-002_create_movable_zone/include/linux/mempolicy.h 2007-02-04 18:44:54.000000000 +0000
+++ linux-2.6.20-mm2-003_mark_hugepages_movable/include/linux/mempolicy.h 2007-02-19 09:13:13.000000000 +0000
@@ -159,7 +159,7 @@ extern void mpol_fix_fork_child_flag(str

extern struct mempolicy default_policy;
extern struct zonelist *huge_zonelist(struct vm_area_struct *vma,
- unsigned long addr);
+ unsigned long addr, gfp_t gfp_flags);
extern unsigned slab_node(struct mempolicy *policy);

extern enum zone_type policy_zone;
@@ -256,9 +256,9 @@ static inline void mpol_fix_fork_child_f
#define set_cpuset_being_rebound(x) do {} while (0)

static inline struct zonelist *huge_zonelist(struct vm_area_struct *vma,
- unsigned long addr)
+ unsigned long addr, gfp_t gfp_flags)
{
- return NODE_DATA(0)->node_zonelists + gfp_zone(GFP_HIGHUSER);
+ return NODE_DATA(0)->node_zonelists + gfp_zone(gfp_flags);
}

static inline int do_migrate_pages(struct mm_struct *mm,
diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.20-mm2-002_create_movable_zone/include/linux/sysctl.h linux-2.6.20-mm2-003_mark_hugepages_movable/include/linux/sysctl.h
--- linux-2.6.20-mm2-002_create_movable_zone/include/linux/sysctl.h 2007-02-19 01:22:32.000000000 +0000
+++ linux-2.6.20-mm2-003_mark_hugepages_movable/include/linux/sysctl.h 2007-02-19 09:13:13.000000000 +0000
@@ -207,6 +207,7 @@ enum
VM_PANIC_ON_OOM=33, /* panic at out-of-memory */
VM_VDSO_ENABLED=34, /* map VDSO into new processes? */
VM_MIN_SLAB=35, /* Percent pages ignored by zone reclaim */
+ VM_HUGETLB_TREAT_MOVABLE=36, /* Allocate hugepages from ZONE_MOVABLE */

/* s390 vm cmm sysctls */
VM_CMM_PAGES=1111,
diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.20-mm2-002_create_movable_zone/kernel/sysctl.c linux-2.6.20-mm2-003_mark_hugepages_movable/kernel/sysctl.c
--- linux-2.6.20-mm2-002_create_movable_zone/kernel/sysctl.c 2007-02-19 01:22:34.000000000 +0000
+++ linux-2.6.20-mm2-003_mark_hugepages_movable/kernel/sysctl.c 2007-02-19 09:13:13.000000000 +0000
@@ -737,6 +737,14 @@ static ctl_table vm_table[] = {
.mode = 0644,
.proc_handler = &proc_dointvec,
},
+ {
+ .ctl_name = VM_HUGETLB_TREAT_MOVABLE,
+ .procname = "hugepages_treat_as_movable",
+ .data = &hugepages_treat_as_movable,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &hugetlb_treat_movable_handler,
+ },
#endif
{
.ctl_name = VM_LOWMEM_RESERVE_RATIO,
diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.20-mm2-002_create_movable_zone/mm/hugetlb.c linux-2.6.20-mm2-003_mark_hugepages_movable/mm/hugetlb.c
--- linux-2.6.20-mm2-002_create_movable_zone/mm/hugetlb.c 2007-02-19 01:22:35.000000000 +0000
+++ linux-2.6.20-mm2-003_mark_hugepages_movable/mm/hugetlb.c 2007-02-19 09:13:13.000000000 +0000
@@ -27,6 +27,9 @@ unsigned long max_huge_pages;
static struct list_head hugepage_freelists[MAX_NUMNODES];
static unsigned int nr_huge_pages_node[MAX_NUMNODES];
static unsigned int free_huge_pages_node[MAX_NUMNODES];
+gfp_t htlb_alloc_mask = GFP_HIGHUSER;
+unsigned long hugepages_treat_as_movable;
+
/*
* Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
*/
@@ -68,12 +71,13 @@ static struct page *dequeue_huge_page(st
{
int nid = numa_node_id();
struct page *page = NULL;
- struct zonelist *zonelist = huge_zonelist(vma, address);
+ struct zonelist *zonelist = huge_zonelist(vma, address,
+ htlb_alloc_mask);
struct zone **z;

for (z = zonelist->zones; *z; z++) {
nid = zone_to_nid(*z);
- if (cpuset_zone_allowed_softwall(*z, GFP_HIGHUSER) &&
+ if (cpuset_zone_allowed_softwall(*z, htlb_alloc_mask) &&
!list_empty(&hugepage_freelists[nid]))
break;
}
@@ -103,7 +107,7 @@ static int alloc_fresh_huge_page(void)
{
static int nid = 0;
struct page *page;
- page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP|__GFP_NOWARN,
+ page = alloc_pages_node(nid, htlb_alloc_mask|__GFP_COMP|__GFP_NOWARN,
HUGETLB_PAGE_ORDER);
nid = next_node(nid, node_online_map);
if (nid == MAX_NUMNODES)
@@ -243,6 +247,19 @@ int hugetlb_sysctl_handler(struct ctl_ta
max_huge_pages = set_max_huge_pages(max_huge_pages);
return 0;
}
+
+int hugetlb_treat_movable_handler(struct 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);
+ if (hugepages_treat_as_movable)
+ htlb_alloc_mask = GFP_HIGH_MOVABLE;
+ else
+ htlb_alloc_mask = GFP_HIGHUSER;
+ return 0;
+}
+
#endif /* CONFIG_SYSCTL */

int hugetlb_report_meminfo(char *buf)
diff -rup -X /usr/src/patchset-0.6/bin//dontdiff linux-2.6.20-mm2-002_create_movable_zone/mm/mempolicy.c linux-2.6.20-mm2-003_mark_hugepages_movable/mm/mempolicy.c
--- linux-2.6.20-mm2-002_create_movable_zone/mm/mempolicy.c 2007-02-19 09:08:29.000000000 +0000
+++ linux-2.6.20-mm2-003_mark_hugepages_movable/mm/mempolicy.c 2007-02-19 09:13:13.000000000 +0000
@@ -1211,7 +1211,8 @@ static inline unsigned interleave_nid(st

#ifdef CONFIG_HUGETLBFS
/* Return a zonelist suitable for a huge page allocation. */
-struct zonelist *huge_zonelist(struct vm_area_struct *vma, unsigned long addr)
+struct zonelist *huge_zonelist(struct vm_area_struct *vma, unsigned long addr,
+ gfp_t gfp_flags)
{
struct mempolicy *pol = get_vma_policy(current, vma, addr);

@@ -1219,7 +1220,7 @@ struct zonelist *huge_zonelist(struct vm
unsigned nid;

nid = interleave_nid(pol, vma, addr, HPAGE_SHIFT);
- return NODE_DATA(nid)->node_zonelists + gfp_zone(GFP_HIGHUSER);
+ return NODE_DATA(nid)->node_zonelists + gfp_zone(gfp_flags);
}
return zonelist_policy(GFP_HIGHUSER, pol);
}
-
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