mm: fix new crash in unmapped_area_topdown()

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / mm / page_alloc.c

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index c3edb624fccf30c303ccff94cf139e090b416d7e..4e8927539299eaa9d83d54d7e94897f0ca69fe5d 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -360,9 +360,11 @@ void prep_compound_page(struct page *page, unsigned long order)
        __SetPageHead(page);
        for (i = 1; i < nr_pages; i++) {
                struct page *p = page + i;
-               __SetPageTail(p);
                set_page_count(p, 0);
                p->first_page = page;
+               /* Make sure p->first_page is always valid for PageTail() */
+               smp_wmb();
+               __SetPageTail(p);
        }
 }
 
@@ -2117,6 +2119,14 @@ __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
                return NULL;
        }
 
+       /*
+        * PM-freezer should be notified that there might be an OOM killer on
+        * its way to kill and wake somebody up. This is too early and we might
+        * end up not killing anything but false positives are acceptable.
+        * See freeze_processes.
+        */
+       note_oom_kill();
+
        /*
         * Go through the zonelist yet one more time, keep very high watermark
         * here, this is only to catch a parallel oom killing, we must fail if
@@ -2337,7 +2347,7 @@ static inline int
 gfp_to_alloc_flags(gfp_t gfp_mask)
 {
        int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
-       const gfp_t wait = gfp_mask & __GFP_WAIT;
+       const bool atomic = !(gfp_mask & (__GFP_WAIT | __GFP_NO_KSWAPD));
 
        /* __GFP_HIGH is assumed to be the same as ALLOC_HIGH to save a branch. */
        BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH);
@@ -2346,20 +2356,20 @@ gfp_to_alloc_flags(gfp_t gfp_mask)
         * The caller may dip into page reserves a bit more if the caller
         * cannot run direct reclaim, or if the caller has realtime scheduling
         * policy or is asking for __GFP_HIGH memory.  GFP_ATOMIC requests will
-        * set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH).
+        * set both ALLOC_HARDER (atomic == true) and ALLOC_HIGH (__GFP_HIGH).
         */
        alloc_flags |= (__force int) (gfp_mask & __GFP_HIGH);
 
-       if (!wait) {
+       if (atomic) {
                /*
-                * Not worth trying to allocate harder for
-                * __GFP_NOMEMALLOC even if it can't schedule.
+                * Not worth trying to allocate harder for __GFP_NOMEMALLOC even
+                * if it can't schedule.
                 */
-               if  (!(gfp_mask & __GFP_NOMEMALLOC))
+               if (!(gfp_mask & __GFP_NOMEMALLOC))
                        alloc_flags |= ALLOC_HARDER;
                /*
-                * Ignore cpuset if GFP_ATOMIC (!wait) rather than fail alloc.
-                * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
+                * Ignore cpuset mems for GFP_ATOMIC rather than fail, see the
+                * comment for __cpuset_node_allowed_softwall().
                 */
                alloc_flags &= ~ALLOC_CPUSET;
        } else if (unlikely(rt_task(current)) && !in_interrupt())
@@ -5050,15 +5060,18 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn)
                                sizeof(arch_zone_lowest_possible_pfn));
        memset(arch_zone_highest_possible_pfn, 0,
                                sizeof(arch_zone_highest_possible_pfn));
-       arch_zone_lowest_possible_pfn[0] = find_min_pfn_with_active_regions();
-       arch_zone_highest_possible_pfn[0] = max_zone_pfn[0];
-       for (i = 1; i < MAX_NR_ZONES; i++) {
+
+       start_pfn = find_min_pfn_with_active_regions();
+
+       for (i = 0; i < MAX_NR_ZONES; i++) {
                if (i == ZONE_MOVABLE)
                        continue;
-               arch_zone_lowest_possible_pfn[i] =
-                       arch_zone_highest_possible_pfn[i-1];
-               arch_zone_highest_possible_pfn[i] =
-                       max(max_zone_pfn[i], arch_zone_lowest_possible_pfn[i]);
+
+               end_pfn = max(max_zone_pfn[i], start_pfn);
+               arch_zone_lowest_possible_pfn[i] = start_pfn;
+               arch_zone_highest_possible_pfn[i] = end_pfn;
+
+               start_pfn = end_pfn;
        }
        arch_zone_lowest_possible_pfn[ZONE_MOVABLE] = 0;
        arch_zone_highest_possible_pfn[ZONE_MOVABLE] = 0;
@@ -6142,6 +6155,10 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
                list_del(&page->lru);
                rmv_page_order(page);
                zone->free_area[order].nr_free--;
+#ifdef CONFIG_HIGHMEM
+               if (PageHighMem(page))
+                       totalhigh_pages -= 1 << order;
+#endif
                for (i = 0; i < (1 << order); i++)
                        SetPageReserved((page+i));
                pfn += (1 << order);