The patch titled
hugetlb: support larger than MAX_ORDER
has been added to the -mm tree. Its filename is
hugetlb-support-larger-than-max_order.patch
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The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: hugetlb: support larger than MAX_ORDER
From: Nick Piggin <npiggin@xxxxxxx>
This is needed on x86-64 to handle GB pages in hugetlbfs, because it is
not practical to enlarge MAX_ORDER to 1GB.
Instead the 1GB pages are only allocated at boot using the bootmem
allocator using the hugepages=... option.
These 1G bootmem pages are never freed. In theory it would be possible to
implement that with some complications, but since it would be a one-way
street (>= MAX_ORDER pages cannot be allocated later) I decided not to
currently.
The >= MAX_ORDER code is not ifdef'ed per architecture. It is not very
big and the ifdef uglyness seemed not be worth it.
Known problems: /proc/meminfo and "free" do not display the memory
allocated for gb pages in "Total". This is a little confusing for the
user.
Acked-by: Andrew Hastings <abh@xxxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxx>
Signed-off-by: Nick Piggin <npiggin@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 81 insertions(+), 2 deletions(-)
diff -puN mm/hugetlb.c~hugetlb-support-larger-than-max_order mm/hugetlb.c
--- a/mm/hugetlb.c~hugetlb-support-larger-than-max_order
+++ a/mm/hugetlb.c
@@ -14,6 +14,7 @@
#include <linux/mempolicy.h>
#include <linux/cpuset.h>
#include <linux/mutex.h>
+#include <linux/bootmem.h>
#include <linux/sysfs.h>
#include <asm/page.h>
@@ -307,7 +308,7 @@ static void free_huge_page(struct page *
INIT_LIST_HEAD(&page->lru);
spin_lock(&hugetlb_lock);
- if (h->surplus_huge_pages_node[nid]) {
+ if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) {
update_and_free_page(h, page);
h->surplus_huge_pages--;
h->surplus_huge_pages_node[nid]--;
@@ -368,6 +369,9 @@ static struct page *alloc_fresh_huge_pag
{
struct page *page;
+ if (h->order >= MAX_ORDER)
+ return NULL;
+
page = alloc_pages_node(nid,
htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
__GFP_REPEAT|__GFP_NOWARN,
@@ -434,6 +438,9 @@ static struct page *alloc_buddy_huge_pag
struct page *page;
unsigned int nid;
+ if (h->order >= MAX_ORDER)
+ return NULL;
+
/*
* Assume we will successfully allocate the surplus page to
* prevent racing processes from causing the surplus to exceed
@@ -610,6 +617,10 @@ static void return_unused_surplus_pages(
/* Uncommit the reservation */
h->resv_huge_pages -= unused_resv_pages;
+ /* Cannot return gigantic pages currently */
+ if (h->order >= MAX_ORDER)
+ return;
+
nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
while (remaining_iterations-- && nr_pages) {
@@ -838,6 +849,63 @@ static struct page *alloc_huge_page(stru
return page;
}
+static __initdata LIST_HEAD(huge_boot_pages);
+
+struct huge_bootmem_page {
+ struct list_head list;
+ struct hstate *hstate;
+};
+
+static int __init alloc_bootmem_huge_page(struct hstate *h)
+{
+ struct huge_bootmem_page *m;
+ int nr_nodes = nodes_weight(node_online_map);
+
+ while (nr_nodes) {
+ void *addr;
+
+ addr = __alloc_bootmem_node_nopanic(
+ NODE_DATA(h->hugetlb_next_nid),
+ huge_page_size(h), huge_page_size(h), 0);
+
+ if (addr) {
+ /*
+ * Use the beginning of the huge page to store the
+ * huge_bootmem_page struct (until gather_bootmem
+ * puts them into the mem_map).
+ */
+ m = addr;
+ if (m)
+ goto found;
+ }
+ hstate_next_node(h);
+ nr_nodes--;
+ }
+ return 0;
+
+found:
+ BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1));
+ /* Put them into a private list first because mem_map is not up yet */
+ list_add(&m->list, &huge_boot_pages);
+ m->hstate = h;
+ return 1;
+}
+
+/* Put bootmem huge pages into the standard lists after mem_map is up */
+static void __init gather_bootmem_prealloc(void)
+{
+ struct huge_bootmem_page *m;
+
+ list_for_each_entry(m, &huge_boot_pages, list) {
+ struct page *page = virt_to_page(m);
+ struct hstate *h = m->hstate;
+ __ClearPageReserved(page);
+ WARN_ON(page_count(page) != 1);
+ prep_compound_page(page, h->order);
+ prep_new_huge_page(h, page, page_to_nid(page));
+ }
+}
+
static void __init hugetlb_init_one_hstate(struct hstate *h)
{
unsigned long i;
@@ -848,7 +916,10 @@ static void __init hugetlb_init_one_hsta
h->hugetlb_next_nid = first_node(node_online_map);
for (i = 0; i < h->max_huge_pages; ++i) {
- if (!alloc_fresh_huge_page(h))
+ if (h->order >= MAX_ORDER) {
+ if (!alloc_bootmem_huge_page(h))
+ break;
+ } else if (!alloc_fresh_huge_page(h))
break;
}
h->max_huge_pages = h->free_huge_pages = h->nr_huge_pages = i;
@@ -881,6 +952,9 @@ static void try_to_free_low(struct hstat
{
int i;
+ if (h->order >= MAX_ORDER)
+ return;
+
for (i = 0; i < MAX_NUMNODES; ++i) {
struct page *page, *next;
struct list_head *freel = &h->hugepage_freelists[i];
@@ -907,6 +981,9 @@ static unsigned long set_max_huge_pages(
{
unsigned long min_count, ret;
+ if (h->order >= MAX_ORDER)
+ return h->max_huge_pages;
+
/*
* Increase the pool size
* First take pages out of surplus state. Then make up the
@@ -1129,6 +1206,8 @@ static int __init hugetlb_init(void)
hugetlb_init_hstates();
+ gather_bootmem_prealloc();
+
report_hugepages();
hugetlb_sysfs_init();
_
Patches currently in -mm which might be from npiggin@xxxxxxx are
hugetlb-fix-lockdep-error.patch
vt-fix-vc_resize-locking.patch
linux-next.patch
spufs-convert-nopfn-to-fault.patch
mspec-convert-nopfn-to-fault.patch
mspec-convert-nopfn-to-fault-fix.patch
mm-remove-nopfn.patch
mm-remove-double-indirection-on-tlb-parameter-to-free_pgd_range-co.patch
hugetlb-guarantee-that-cow-faults-for-a-process-that-called-mmapmap_private-on-hugetlbfs-will-succeed-build-fix.patch
hugetlb-factor-out-prep_new_huge_page.patch
hugetlb-modular-state-for-hugetlb-page-size.patch
hugetlb-modular-state-for-hugetlb-page-size-checkpatch-fixes.patch
hugetlb-multiple-hstates-for-multiple-page-sizes.patch
hugetlb-multiple-hstates-for-multiple-page-sizes-checkpatch-fixes.patch
hugetlbfs-per-mount-huge-page-sizes.patch
hugetlb-new-sysfs-interface.patch
hugetlb-abstract-numa-round-robin-selection.patch
mm-introduce-non-panic-alloc_bootmem.patch
mm-export-prep_compound_page-to-mm.patch
hugetlb-support-larger-than-max_order.patch
hugetlb-support-boot-allocate-different-sizes.patch
hugetlb-printk-cleanup.patch
hugetlb-introduce-pud_huge.patch
x86-support-gb-hugepages-on-64-bit.patch
x86-add-hugepagesz-option-on-64-bit.patch
hugetlb-override-default-huge-page-size.patch
hugetlb-allow-arch-overried-hugepage-allocation.patch
powerpc-function-to-allocate-gigantic-hugepages.patch
powerpc-scan-device-tree-for-gigantic-pages.patch
powerpc-define-support-for-16g-hugepages.patch
fs-check-for-statfs-overflow.patch
powerpc-support-multiple-hugepage-sizes.patch
x86-implement-pte_special.patch
mm-introduce-get_user_pages_fast.patch
mm-introduce-get_user_pages_fast-checkpatch-fixes.patch
x86-lockless-get_user_pages_fast.patch
x86-lockless-get_user_pages_fast-checkpatch-fixes.patch
x86-lockless-get_user_pages_fast-fix.patch
x86-lockless-get_user_pages_fast-fix-warning.patch
dio-use-get_user_pages_fast.patch
splice-use-get_user_pages_fast.patch
mm-readahead-scan-lockless.patch
radix-tree-add-gang_lookup_slot-gang_lookup_slot_tag.patch
mm-speculative-page-references.patch
mm-lockless-pagecache.patch
mm-spinlock-tree_lock.patch
powerpc-implement-pte_special.patch
powerpc-lockless-get_user_pages_fast.patch
vmscan-move-isolate_lru_page-to-vmscanc.patch
vmscan-mlocked-pages-are-non-reclaimable.patch
vmscan-handle-mlocked-pages-during-map-remap-unmap.patch
vmscan-mlocked-pages-statistics.patch
reiser4.patch
likeliness-accounting-change-and-cleanup.patch
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