thp: compound_trans_order
Andrea Arcangeli [Thu, 13 Jan 2011 23:47:16 +0000 (15:47 -0800)]
Read compound_trans_order safe. Noop for CONFIG_TRANSPARENT_HUGEPAGE=n.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/mm.h
mm/memcontrol.c
mm/memory-failure.c

index 9c2695b..ce97a2b 100644 (file)
@@ -450,6 +450,20 @@ static inline int compound_order(struct page *page)
        return (unsigned long)page[1].lru.prev;
 }
 
+static inline int compound_trans_order(struct page *page)
+{
+       int order;
+       unsigned long flags;
+
+       if (!PageHead(page))
+               return 0;
+
+       flags = compound_lock_irqsave(page);
+       order = compound_order(page);
+       compound_unlock_irqrestore(page, flags);
+       return order;
+}
+
 static inline void set_compound_order(struct page *page, unsigned long order)
 {
        page[1].lru.prev = (void *)order;
index f4ea341..741206f 100644 (file)
@@ -1027,10 +1027,6 @@ mem_cgroup_get_reclaim_stat_from_page(struct page *page)
 {
        struct page_cgroup *pc;
        struct mem_cgroup_per_zone *mz;
-       int page_size = PAGE_SIZE;
-
-       if (PageTransHuge(page))
-               page_size <<= compound_order(page);
 
        if (mem_cgroup_disabled())
                return NULL;
@@ -2286,8 +2282,10 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
        int ret;
        int page_size = PAGE_SIZE;
 
-       if (PageTransHuge(page))
+       if (PageTransHuge(page)) {
                page_size <<= compound_order(page);
+               VM_BUG_ON(!PageTransHuge(page));
+       }
 
        pc = lookup_page_cgroup(page);
        /* can happen at boot */
@@ -2558,8 +2556,10 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
        if (PageSwapCache(page))
                return NULL;
 
-       if (PageTransHuge(page))
+       if (PageTransHuge(page)) {
                page_size <<= compound_order(page);
+               VM_BUG_ON(!PageTransHuge(page));
+       }
 
        count = page_size >> PAGE_SHIFT;
        /*
index 1b43d0f..548fbd7 100644 (file)
@@ -203,7 +203,7 @@ static int kill_proc_ao(struct task_struct *t, unsigned long addr, int trapno,
 #ifdef __ARCH_SI_TRAPNO
        si.si_trapno = trapno;
 #endif
-       si.si_addr_lsb = compound_order(compound_head(page)) + PAGE_SHIFT;
+       si.si_addr_lsb = compound_trans_order(compound_head(page)) + PAGE_SHIFT;
        /*
         * Don't use force here, it's convenient if the signal
         * can be temporarily blocked.
@@ -930,7 +930,7 @@ static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
 static void set_page_hwpoison_huge_page(struct page *hpage)
 {
        int i;
-       int nr_pages = 1 << compound_order(hpage);
+       int nr_pages = 1 << compound_trans_order(hpage);
        for (i = 0; i < nr_pages; i++)
                SetPageHWPoison(hpage + i);
 }
@@ -938,7 +938,7 @@ static void set_page_hwpoison_huge_page(struct page *hpage)
 static void clear_page_hwpoison_huge_page(struct page *hpage)
 {
        int i;
-       int nr_pages = 1 << compound_order(hpage);
+       int nr_pages = 1 << compound_trans_order(hpage);
        for (i = 0; i < nr_pages; i++)
                ClearPageHWPoison(hpage + i);
 }
@@ -968,7 +968,7 @@ int __memory_failure(unsigned long pfn, int trapno, int flags)
                return 0;
        }
 
-       nr_pages = 1 << compound_order(hpage);
+       nr_pages = 1 << compound_trans_order(hpage);
        atomic_long_add(nr_pages, &mce_bad_pages);
 
        /*
@@ -1166,7 +1166,7 @@ int unpoison_memory(unsigned long pfn)
                return 0;
        }
 
-       nr_pages = 1 << compound_order(page);
+       nr_pages = 1 << compound_trans_order(page);
 
        if (!get_page_unless_zero(page)) {
                /*
@@ -1304,7 +1304,7 @@ static int soft_offline_huge_page(struct page *page, int flags)
        }
 done:
        if (!PageHWPoison(hpage))
-               atomic_long_add(1 << compound_order(hpage), &mce_bad_pages);
+               atomic_long_add(1 << compound_trans_order(hpage), &mce_bad_pages);
        set_page_hwpoison_huge_page(hpage);
        dequeue_hwpoisoned_huge_page(hpage);
        /* keep elevated page count for bad page */