Re: [PATCH 1/8] mm: introduce PageHuge() for testing huge/giganticpages
From: Wu Fengguang
Date: Fri May 08 2009 - 08:21:52 EST
On Fri, May 08, 2009 at 07:40:18PM +0800, Ingo Molnar wrote:
>
> * Wu Fengguang <fengguang.wu@xxxxxxxxx> wrote:
>
> > Introduce PageHuge(), which identifies huge/gigantic pages
> > by their dedicated compound destructor functions.
[snip]
> > +#ifdef CONFIG_HUGETLBFS
> > +void free_huge_page(struct page *page);
> > +void free_gigantic_page(struct page *page);
> > +
> > +static inline int PageHuge(struct page *page)
> > +{
> > + compound_page_dtor *dtor;
> > +
> > + if (!PageCompound(page))
> > + return 0;
> > +
> > + page = compound_head(page);
> > + dtor = get_compound_page_dtor(page);
> > +
> > + return dtor == free_huge_page ||
> > + dtor == free_gigantic_page;
> > +}
>
> Hm, this function is _way_ too large to be inlined.
Thanks, updated patch as follows.
---
Subject: mm: introduce PageHuge() for testing huge/gigantic pages
Introduce PageHuge(), which identifies huge/gigantic pages
by their dedicated compound destructor functions.
Also move prep_compound_gigantic_page() to hugetlb.c and
make __free_pages_ok() non-static.
Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
---
include/linux/mm.h | 9 +++
mm/hugetlb.c | 98 ++++++++++++++++++++++++++++---------------
mm/internal.h | 6 +-
mm/page_alloc.c | 21 ---------
4 files changed, 79 insertions(+), 55 deletions(-)
--- linux.orig/mm/page_alloc.c
+++ linux/mm/page_alloc.c
@@ -77,8 +77,6 @@ int percpu_pagelist_fraction;
int pageblock_order __read_mostly;
#endif
-static void __free_pages_ok(struct page *page, unsigned int order);
-
/*
* results with 256, 32 in the lowmem_reserve sysctl:
* 1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
@@ -298,23 +296,6 @@ void prep_compound_page(struct page *pag
}
}
-#ifdef CONFIG_HUGETLBFS
-void prep_compound_gigantic_page(struct page *page, unsigned long order)
-{
- int i;
- int nr_pages = 1 << order;
- struct page *p = page + 1;
-
- set_compound_page_dtor(page, free_compound_page);
- set_compound_order(page, order);
- __SetPageHead(page);
- for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
- __SetPageTail(p);
- p->first_page = page;
- }
-}
-#endif
-
static int destroy_compound_page(struct page *page, unsigned long order)
{
int i;
@@ -544,7 +525,7 @@ static void free_one_page(struct zone *z
spin_unlock(&zone->lock);
}
-static void __free_pages_ok(struct page *page, unsigned int order)
+void __free_pages_ok(struct page *page, unsigned int order)
{
unsigned long flags;
int i;
--- linux.orig/mm/hugetlb.c
+++ linux/mm/hugetlb.c
@@ -578,39 +578,9 @@ static void free_huge_page(struct page *
hugetlb_put_quota(mapping, 1);
}
-/*
- * Increment or decrement surplus_huge_pages. Keep node-specific counters
- * balanced by operating on them in a round-robin fashion.
- * Returns 1 if an adjustment was made.
- */
-static int adjust_pool_surplus(struct hstate *h, int delta)
+static void free_gigantic_page(struct page *page)
{
- static int prev_nid;
- int nid = prev_nid;
- int ret = 0;
-
- VM_BUG_ON(delta != -1 && delta != 1);
- do {
- nid = next_node(nid, node_online_map);
- if (nid == MAX_NUMNODES)
- nid = first_node(node_online_map);
-
- /* To shrink on this node, there must be a surplus page */
- if (delta < 0 && !h->surplus_huge_pages_node[nid])
- continue;
- /* Surplus cannot exceed the total number of pages */
- if (delta > 0 && h->surplus_huge_pages_node[nid] >=
- h->nr_huge_pages_node[nid])
- continue;
-
- h->surplus_huge_pages += delta;
- h->surplus_huge_pages_node[nid] += delta;
- ret = 1;
- break;
- } while (nid != prev_nid);
-
- prev_nid = nid;
- return ret;
+ __free_pages_ok(page, compound_order(page));
}
static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
@@ -623,6 +593,35 @@ static void prep_new_huge_page(struct hs
put_page(page); /* free it into the hugepage allocator */
}
+static void prep_compound_gigantic_page(struct page *page, unsigned long order)
+{
+ int i;
+ int nr_pages = 1 << order;
+ struct page *p = page + 1;
+
+ set_compound_page_dtor(page, free_gigantic_page);
+ set_compound_order(page, order);
+ __SetPageHead(page);
+ for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
+ __SetPageTail(p);
+ p->first_page = page;
+ }
+}
+
+int PageHuge(struct page *page)
+{
+ compound_page_dtor *dtor;
+
+ if (!PageCompound(page))
+ return 0;
+
+ page = compound_head(page);
+ dtor = get_compound_page_dtor(page);
+
+ return dtor == free_huge_page ||
+ dtor == free_gigantic_page;
+}
+
static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
{
struct page *page;
@@ -1140,6 +1139,41 @@ static inline void try_to_free_low(struc
}
#endif
+/*
+ * Increment or decrement surplus_huge_pages. Keep node-specific counters
+ * balanced by operating on them in a round-robin fashion.
+ * Returns 1 if an adjustment was made.
+ */
+static int adjust_pool_surplus(struct hstate *h, int delta)
+{
+ static int prev_nid;
+ int nid = prev_nid;
+ int ret = 0;
+
+ VM_BUG_ON(delta != -1 && delta != 1);
+ do {
+ nid = next_node(nid, node_online_map);
+ if (nid == MAX_NUMNODES)
+ nid = first_node(node_online_map);
+
+ /* To shrink on this node, there must be a surplus page */
+ if (delta < 0 && !h->surplus_huge_pages_node[nid])
+ continue;
+ /* Surplus cannot exceed the total number of pages */
+ if (delta > 0 && h->surplus_huge_pages_node[nid] >=
+ h->nr_huge_pages_node[nid])
+ continue;
+
+ h->surplus_huge_pages += delta;
+ h->surplus_huge_pages_node[nid] += delta;
+ ret = 1;
+ break;
+ } while (nid != prev_nid);
+
+ prev_nid = nid;
+ return ret;
+}
+
#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count)
{
--- linux.orig/include/linux/mm.h
+++ linux/include/linux/mm.h
@@ -355,6 +355,15 @@ static inline void set_compound_order(st
page[1].lru.prev = (void *)order;
}
+#ifdef CONFIG_HUGETLBFS
+int PageHuge(struct page *page);
+#else
+static inline int PageHuge(struct page *page)
+{
+ return 0;
+}
+#endif
+
/*
* Multiple processes may "see" the same page. E.g. for untouched
* mappings of /dev/null, all processes see the same page full of
--- linux.orig/mm/internal.h
+++ linux/mm/internal.h
@@ -16,9 +16,6 @@
void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
unsigned long floor, unsigned long ceiling);
-extern void prep_compound_page(struct page *page, unsigned long order);
-extern void prep_compound_gigantic_page(struct page *page, unsigned long order);
-
static inline void set_page_count(struct page *page, int v)
{
atomic_set(&page->_count, v);
@@ -51,6 +48,9 @@ extern void putback_lru_page(struct page
*/
extern unsigned long highest_memmap_pfn;
extern void __free_pages_bootmem(struct page *page, unsigned int order);
+extern void __free_pages_ok(struct page *page, unsigned int order);
+extern void prep_compound_page(struct page *page, unsigned long order);
+
/*
* function for dealing with page's order in buddy system.
--
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