hugetlb: multiple hstates for multiple page sizes

Add basic support for more than one hstate in hugetlbfs.  This is the key
to supporting multiple hugetlbfs page sizes at once.

- Rather than a single hstate, we now have an array, with an iterator
- default_hstate continues to be the struct hstate which we use by default
- Add functions for architectures to register new hstates

[akpm@linux-foundation.org: coding-style fixes]
Acked-by: Adam Litke <agl@us.ibm.com>
Acked-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 121 insertions, 27 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 0d8153e25f09..82378d44a0c5 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -22,12 +22,19 @@
 #include "internal.h"
 
 const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
-unsigned long max_huge_pages;
-unsigned long sysctl_overcommit_huge_pages;
 static gfp_t htlb_alloc_mask = GFP_HIGHUSER;
 unsigned long hugepages_treat_as_movable;
 
-struct hstate default_hstate;
+static int max_hstate;
+unsigned int default_hstate_idx;
+struct hstate hstates[HUGE_MAX_HSTATE];
+
+/* for command line parsing */
+static struct hstate * __initdata parsed_hstate;
+static unsigned long __initdata default_hstate_max_huge_pages;
+
+#define for_each_hstate(h) \
+        for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++)
 
 /*
  * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
@@ -454,13 +461,24 @@ static void update_and_free_page(struct hstate *h, struct page *page)
         __free_pages(page, huge_page_order(h));
 }
 
+struct hstate *size_to_hstate(unsigned long size)
+{
+        struct hstate *h;
+
+        for_each_hstate(h) {
+                if (huge_page_size(h) == size)
+                        return h;
+        }
+        return NULL;
+}
+
 static void free_huge_page(struct page *page)
 {
         /*
          * Can't pass hstate in here because it is called from the
          * compound page destructor.
          */
-        struct hstate *h = &default_hstate;
+        struct hstate *h = page_hstate(page);
         int nid = page_to_nid(page);
         struct address_space *mapping;
 
@@ -887,39 +905,94 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma,
         return page;
 }
 
-static int __init hugetlb_init(void)
+static void __init hugetlb_init_one_hstate(struct hstate *h)
 {
         unsigned long i;
-        struct hstate *h = &default_hstate;
-
-        if (HPAGE_SHIFT == 0)
-                return 0;
-
-        if (!h->order) {
-                h->order = HPAGE_SHIFT - PAGE_SHIFT;
-                h->mask = HPAGE_MASK;
-        }
 
         for (i = 0; i < MAX_NUMNODES; ++i)
                 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
 
         h->hugetlb_next_nid = first_node(node_online_map);
 
-        for (i = 0; i < max_huge_pages; ++i) {
+        for (i = 0; i < h->max_huge_pages; ++i) {
                 if (!alloc_fresh_huge_page(h))
                         break;
         }
-        max_huge_pages = h->free_huge_pages = h->nr_huge_pages = i;
-        printk(KERN_INFO "Total HugeTLB memory allocated, %ld\n",
-                        h->free_huge_pages);
+        h->max_huge_pages = h->free_huge_pages = h->nr_huge_pages = i;
+}
+
+static void __init hugetlb_init_hstates(void)
+{
+        struct hstate *h;
+
+        for_each_hstate(h) {
+                hugetlb_init_one_hstate(h);
+        }
+}
+
+static void __init report_hugepages(void)
+{
+        struct hstate *h;
+
+        for_each_hstate(h) {
+                printk(KERN_INFO "Total HugeTLB memory allocated, "
+                                "%ld %dMB pages\n",
+                                h->free_huge_pages,
+                                1 << (h->order + PAGE_SHIFT - 20));
+        }
+}
+
+static int __init hugetlb_init(void)
+{
+        BUILD_BUG_ON(HPAGE_SHIFT == 0);
+
+        if (!size_to_hstate(HPAGE_SIZE)) {
+                hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
+                parsed_hstate->max_huge_pages = default_hstate_max_huge_pages;
+        }
+        default_hstate_idx = size_to_hstate(HPAGE_SIZE) - hstates;
+
+        hugetlb_init_hstates();
+
+        report_hugepages();
+
         return 0;
 }
 module_init(hugetlb_init);
 
+/* Should be called on processing a hugepagesz=... option */
+void __init hugetlb_add_hstate(unsigned order)
+{
+        struct hstate *h;
+        if (size_to_hstate(PAGE_SIZE << order)) {
+                printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n");
+                return;
+        }
+        BUG_ON(max_hstate >= HUGE_MAX_HSTATE);
+        BUG_ON(order == 0);
+        h = &hstates[max_hstate++];
+        h->order = order;
+        h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
+        hugetlb_init_one_hstate(h);
+        parsed_hstate = h;
+}
+
 static int __init hugetlb_setup(char *s)
 {
-        if (sscanf(s, "%lu", &max_huge_pages) <= 0)
-                max_huge_pages = 0;
+        unsigned long *mhp;
+
+        /*
+         * !max_hstate means we haven't parsed a hugepagesz= parameter yet,
+         * so this hugepages= parameter goes to the "default hstate".
+         */
+        if (!max_hstate)
+                mhp = &default_hstate_max_huge_pages;
+        else
+                mhp = &parsed_hstate->max_huge_pages;
+
+        if (sscanf(s, "%lu", mhp) <= 0)
+                *mhp = 0;
+
         return 1;
 }
 __setup("hugepages=", hugetlb_setup);
@@ -950,7 +1023,7 @@ static void try_to_free_low(struct hstate *h, unsigned long count)
                         if (PageHighMem(page))
                                 continue;
                         list_del(&page->lru);
-                        update_and_free_page(page);
+                        update_and_free_page(h, page);
                         h->free_huge_pages--;
                         h->free_huge_pages_node[page_to_nid(page)]--;
                 }
@@ -963,10 +1036,9 @@ static inline void try_to_free_low(struct hstate *h, unsigned long count)
 #endif
 
 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
-static unsigned long set_max_huge_pages(unsigned long count)
+static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count)
 {
         unsigned long min_count, ret;
-        struct hstate *h = &default_hstate;
 
         /*
          * Increase the pool size
@@ -1037,8 +1109,19 @@ int hugetlb_sysctl_handler(struct ctl_table *table, int write,
                            struct file *file, void __user *buffer,
                            size_t *length, loff_t *ppos)
 {
+        struct hstate *h = &default_hstate;
+        unsigned long tmp;
+
+        if (!write)
+                tmp = h->max_huge_pages;
+
+        table->data = &tmp;
+        table->maxlen = sizeof(unsigned long);
         proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
-        max_huge_pages = set_max_huge_pages(max_huge_pages);
+
+        if (write)
+                h->max_huge_pages = set_max_huge_pages(h, tmp);
+
         return 0;
 }
 
@@ -1059,10 +1142,21 @@ int hugetlb_overcommit_handler(struct ctl_table *table, int write,
                         size_t *length, loff_t *ppos)
 {
         struct hstate *h = &default_hstate;
+        unsigned long tmp;
+
+        if (!write)
+                tmp = h->nr_overcommit_huge_pages;
+
+        table->data = &tmp;
+        table->maxlen = sizeof(unsigned long);
         proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
-        spin_lock(&hugetlb_lock);
-        h->nr_overcommit_huge_pages = sysctl_overcommit_huge_pages;
-        spin_unlock(&hugetlb_lock);
+
+        if (write) {
+                spin_lock(&hugetlb_lock);
+                h->nr_overcommit_huge_pages = tmp;
+                spin_unlock(&hugetlb_lock);
+        }
+
         return 0;
 }