SLUB: minimum alignment fixes

[linux-drm-fsl-dcu.git] / mm / hugetlb.c

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index cb362f761f174b926c1c41b72ec2940c5d45763d..a45d1f0691cecb63e088d02fb3ff287f025e4d78 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -140,6 +140,8 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma,
        return page;
 
 fail:
+       if (vma->vm_flags & VM_MAYSHARE)
+               resv_huge_pages++;
        spin_unlock(&hugetlb_lock);
        return NULL;
 }
@@ -172,6 +174,17 @@ static int __init hugetlb_setup(char *s)
 }
 __setup("hugepages=", hugetlb_setup);
 
+static unsigned int cpuset_mems_nr(unsigned int *array)
+{
+       int node;
+       unsigned int nr = 0;
+
+       for_each_node_mask(node, cpuset_current_mems_allowed)
+               nr += array[node];
+
+       return nr;
+}
+
 #ifdef CONFIG_SYSCTL
 static void update_and_free_page(struct page *page)
 {
@@ -313,9 +326,10 @@ static void set_huge_ptep_writable(struct vm_area_struct *vma,
        pte_t entry;
 
        entry = pte_mkwrite(pte_mkdirty(*ptep));
-       ptep_set_access_flags(vma, address, ptep, entry, 1);
-       update_mmu_cache(vma, address, entry);
-       lazy_mmu_prot_update(entry);
+       if (ptep_set_access_flags(vma, address, ptep, entry, 1)) {
+               update_mmu_cache(vma, address, entry);
+               lazy_mmu_prot_update(entry);
+       }
 }
 
 
@@ -389,6 +403,8 @@ void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
                        continue;
 
                page = pte_page(pte);
+               if (pte_dirty(pte))
+                       set_page_dirty(page);
                list_add(&page->lru, &page_list);
        }
        spin_unlock(&mm->page_table_lock);
@@ -815,6 +831,26 @@ int hugetlb_reserve_pages(struct inode *inode, long from, long to)
        chg = region_chg(&inode->i_mapping->private_list, from, to);
        if (chg < 0)
                return chg;
+       /*
+        * When cpuset is configured, it breaks the strict hugetlb page
+        * reservation as the accounting is done on a global variable. Such
+        * reservation is completely rubbish in the presence of cpuset because
+        * the reservation is not checked against page availability for the
+        * current cpuset. Application can still potentially OOM'ed by kernel
+        * with lack of free htlb page in cpuset that the task is in.
+        * Attempt to enforce strict accounting with cpuset is almost
+        * impossible (or too ugly) because cpuset is too fluid that
+        * task or memory node can be dynamically moved between cpusets.
+        *
+        * The change of semantics for shared hugetlb mapping with cpuset is
+        * undesirable. However, in order to preserve some of the semantics,
+        * we fall back to check against current free page availability as
+        * a best attempt and hopefully to minimize the impact of changing
+        * semantics that cpuset has.
+        */
+       if (chg > cpuset_mems_nr(free_huge_pages_node))
+               return -ENOMEM;
+
        ret = hugetlb_acct_memory(chg);
        if (ret < 0)
                return ret;