[v7,2/3] mm: Move buddy list manipulations into helpers
diff mbox series

Message ID 154690327612.676627.7469591833063917773.stgit@dwillia2-desk3.amr.corp.intel.com
State New
Headers show
Series
  • mm: Randomize free memory
Related show

Commit Message

Dan Williams Jan. 7, 2019, 11:21 p.m. UTC
In preparation for runtime randomization of the zone lists, take all
(well, most of) the list_*() functions in the buddy allocator and put
them in helper functions. Provide a common control point for injecting
additional behavior when freeing pages.

Cc: Michal Hocko <mhocko@suse.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 include/linux/mm.h       |    3 --
 include/linux/mm_types.h |    3 ++
 include/linux/mmzone.h   |   51 ++++++++++++++++++++++++++++++++++
 mm/compaction.c          |    4 +--
 mm/page_alloc.c          |   70 ++++++++++++++++++----------------------------
 5 files changed, 84 insertions(+), 47 deletions(-)

Comments

Michal Hocko Jan. 25, 2019, 2:30 p.m. UTC | #1
On Mon 07-01-19 15:21:16, Dan Williams wrote:
> In preparation for runtime randomization of the zone lists, take all
> (well, most of) the list_*() functions in the buddy allocator and put
> them in helper functions. Provide a common control point for injecting
> additional behavior when freeing pages.

Looks good in general and it actually makes the code more readable.
One nit below

[...]
> +static inline void rmv_page_order(struct page *page)
> +{
> +	__ClearPageBuddy(page);
> +	set_page_private(page, 0);
> +}
> +

I guess we do not really need this helper and simply squash it to its
only user.

Acked-by: Michal Hocko <mhocko@suse.com>
Dan Williams Jan. 29, 2019, 7:27 p.m. UTC | #2
On Fri, Jan 25, 2019 at 6:31 AM Michal Hocko <mhocko@kernel.org> wrote:
>
> On Mon 07-01-19 15:21:16, Dan Williams wrote:
> > In preparation for runtime randomization of the zone lists, take all
> > (well, most of) the list_*() functions in the buddy allocator and put
> > them in helper functions. Provide a common control point for injecting
> > additional behavior when freeing pages.
>
> Looks good in general and it actually makes the code more readable.
> One nit below
>
> [...]
> > +static inline void rmv_page_order(struct page *page)
> > +{
> > +     __ClearPageBuddy(page);
> > +     set_page_private(page, 0);
> > +}
> > +
>
> I guess we do not really need this helper and simply squash it to its
> only user.

Ok.

>
> Acked-by: Michal Hocko <mhocko@suse.com>

Thanks.

>
> --
> Michal Hocko
> SUSE Labs

Patch
diff mbox series

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 80bb6408fe73..1621acd10f83 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -500,9 +500,6 @@  static inline void vma_set_anonymous(struct vm_area_struct *vma)
 struct mmu_gather;
 struct inode;
 
-#define page_private(page)		((page)->private)
-#define set_page_private(page, v)	((page)->private = (v))
-
 #if !defined(__HAVE_ARCH_PTE_DEVMAP) || !defined(CONFIG_TRANSPARENT_HUGEPAGE)
 static inline int pmd_devmap(pmd_t pmd)
 {
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 2c471a2c43fa..1c7dc7ffa288 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -214,6 +214,9 @@  struct page {
 #define PAGE_FRAG_CACHE_MAX_SIZE	__ALIGN_MASK(32768, ~PAGE_MASK)
 #define PAGE_FRAG_CACHE_MAX_ORDER	get_order(PAGE_FRAG_CACHE_MAX_SIZE)
 
+#define page_private(page)		((page)->private)
+#define set_page_private(page, v)	((page)->private = (v))
+
 struct page_frag_cache {
 	void * va;
 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 8c37a023a790..b78a45e0b11c 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -18,6 +18,8 @@ 
 #include <linux/pageblock-flags.h>
 #include <linux/page-flags-layout.h>
 #include <linux/atomic.h>
+#include <linux/mm_types.h>
+#include <linux/page-flags.h>
 #include <asm/page.h>
 
 /* Free memory management - zoned buddy allocator.  */
@@ -98,6 +100,55 @@  struct free_area {
 	unsigned long		nr_free;
 };
 
+/* Used for pages not on another list */
+static inline void add_to_free_area(struct page *page, struct free_area *area,
+			     int migratetype)
+{
+	list_add(&page->lru, &area->free_list[migratetype]);
+	area->nr_free++;
+}
+
+/* Used for pages not on another list */
+static inline void add_to_free_area_tail(struct page *page, struct free_area *area,
+				  int migratetype)
+{
+	list_add_tail(&page->lru, &area->free_list[migratetype]);
+	area->nr_free++;
+}
+
+/* Used for pages which are on another list */
+static inline void move_to_free_area(struct page *page, struct free_area *area,
+			     int migratetype)
+{
+	list_move(&page->lru, &area->free_list[migratetype]);
+}
+
+static inline struct page *get_page_from_free_area(struct free_area *area,
+					    int migratetype)
+{
+	return list_first_entry_or_null(&area->free_list[migratetype],
+					struct page, lru);
+}
+
+static inline void rmv_page_order(struct page *page)
+{
+	__ClearPageBuddy(page);
+	set_page_private(page, 0);
+}
+
+static inline void del_page_from_free_area(struct page *page,
+		struct free_area *area, int migratetype)
+{
+	list_del(&page->lru);
+	rmv_page_order(page);
+	area->nr_free--;
+}
+
+static inline bool free_area_empty(struct free_area *area, int migratetype)
+{
+	return list_empty(&area->free_list[migratetype]);
+}
+
 struct pglist_data;
 
 /*
diff --git a/mm/compaction.c b/mm/compaction.c
index ef29490b0f46..a22ac7ab65c5 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1359,13 +1359,13 @@  static enum compact_result __compact_finished(struct zone *zone,
 		bool can_steal;
 
 		/* Job done if page is free of the right migratetype */
-		if (!list_empty(&area->free_list[migratetype]))
+		if (!free_area_empty(area, migratetype))
 			return COMPACT_SUCCESS;
 
 #ifdef CONFIG_CMA
 		/* MIGRATE_MOVABLE can fallback on MIGRATE_CMA */
 		if (migratetype == MIGRATE_MOVABLE &&
-			!list_empty(&area->free_list[MIGRATE_CMA]))
+			!free_area_empty(area, MIGRATE_CMA))
 			return COMPACT_SUCCESS;
 #endif
 		/*
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2adcd6da8a07..0b4791a2dd43 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -743,12 +743,6 @@  static inline void set_page_order(struct page *page, unsigned int order)
 	__SetPageBuddy(page);
 }
 
-static inline void rmv_page_order(struct page *page)
-{
-	__ClearPageBuddy(page);
-	set_page_private(page, 0);
-}
-
 /*
  * This function checks whether a page is free && is the buddy
  * we can coalesce a page and its buddy if
@@ -849,13 +843,11 @@  static inline void __free_one_page(struct page *page,
 		 * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page,
 		 * merge with it and move up one order.
 		 */
-		if (page_is_guard(buddy)) {
+		if (page_is_guard(buddy))
 			clear_page_guard(zone, buddy, order, migratetype);
-		} else {
-			list_del(&buddy->lru);
-			zone->free_area[order].nr_free--;
-			rmv_page_order(buddy);
-		}
+		else
+			del_page_from_free_area(buddy, &zone->free_area[order],
+					migratetype);
 		combined_pfn = buddy_pfn & pfn;
 		page = page + (combined_pfn - pfn);
 		pfn = combined_pfn;
@@ -905,15 +897,13 @@  static inline void __free_one_page(struct page *page,
 		higher_buddy = higher_page + (buddy_pfn - combined_pfn);
 		if (pfn_valid_within(buddy_pfn) &&
 		    page_is_buddy(higher_page, higher_buddy, order + 1)) {
-			list_add_tail(&page->lru,
-				&zone->free_area[order].free_list[migratetype]);
-			goto out;
+			add_to_free_area_tail(page, &zone->free_area[order],
+					      migratetype);
+			return;
 		}
 	}
 
-	list_add(&page->lru, &zone->free_area[order].free_list[migratetype]);
-out:
-	zone->free_area[order].nr_free++;
+	add_to_free_area(page, &zone->free_area[order], migratetype);
 }
 
 /*
@@ -1852,7 +1842,7 @@  static inline void expand(struct zone *zone, struct page *page,
 		if (set_page_guard(zone, &page[size], high, migratetype))
 			continue;
 
-		list_add(&page[size].lru, &area->free_list[migratetype]);
+		add_to_free_area(&page[size], area, migratetype);
 		area->nr_free++;
 		set_page_order(&page[size], high);
 	}
@@ -1994,13 +1984,10 @@  struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
 	/* Find a page of the appropriate size in the preferred list */
 	for (current_order = order; current_order < MAX_ORDER; ++current_order) {
 		area = &(zone->free_area[current_order]);
-		page = list_first_entry_or_null(&area->free_list[migratetype],
-							struct page, lru);
+		page = get_page_from_free_area(area, migratetype);
 		if (!page)
 			continue;
-		list_del(&page->lru);
-		rmv_page_order(page);
-		area->nr_free--;
+		del_page_from_free_area(page, area, migratetype);
 		expand(zone, page, order, current_order, area, migratetype);
 		set_pcppage_migratetype(page, migratetype);
 		return page;
@@ -2086,8 +2073,7 @@  static int move_freepages(struct zone *zone,
 		}
 
 		order = page_order(page);
-		list_move(&page->lru,
-			  &zone->free_area[order].free_list[migratetype]);
+		move_to_free_area(page, &zone->free_area[order], migratetype);
 		page += 1 << order;
 		pages_moved += 1 << order;
 	}
@@ -2263,7 +2249,7 @@  static void steal_suitable_fallback(struct zone *zone, struct page *page,
 
 single_page:
 	area = &zone->free_area[current_order];
-	list_move(&page->lru, &area->free_list[start_type]);
+	move_to_free_area(page, area, start_type);
 }
 
 /*
@@ -2287,7 +2273,7 @@  int find_suitable_fallback(struct free_area *area, unsigned int order,
 		if (fallback_mt == MIGRATE_TYPES)
 			break;
 
-		if (list_empty(&area->free_list[fallback_mt]))
+		if (free_area_empty(area, fallback_mt))
 			continue;
 
 		if (can_steal_fallback(order, migratetype))
@@ -2374,9 +2360,7 @@  static bool unreserve_highatomic_pageblock(const struct alloc_context *ac,
 		for (order = 0; order < MAX_ORDER; order++) {
 			struct free_area *area = &(zone->free_area[order]);
 
-			page = list_first_entry_or_null(
-					&area->free_list[MIGRATE_HIGHATOMIC],
-					struct page, lru);
+			page = get_page_from_free_area(area, MIGRATE_HIGHATOMIC);
 			if (!page)
 				continue;
 
@@ -2499,8 +2483,7 @@  __rmqueue_fallback(struct zone *zone, int order, int start_migratetype,
 	VM_BUG_ON(current_order == MAX_ORDER);
 
 do_steal:
-	page = list_first_entry(&area->free_list[fallback_mt],
-							struct page, lru);
+	page = get_page_from_free_area(area, fallback_mt);
 
 	steal_suitable_fallback(zone, page, alloc_flags, start_migratetype,
 								can_steal);
@@ -2937,6 +2920,7 @@  EXPORT_SYMBOL_GPL(split_page);
 
 int __isolate_free_page(struct page *page, unsigned int order)
 {
+	struct free_area *area = &page_zone(page)->free_area[order];
 	unsigned long watermark;
 	struct zone *zone;
 	int mt;
@@ -2961,9 +2945,8 @@  int __isolate_free_page(struct page *page, unsigned int order)
 	}
 
 	/* Remove page from free list */
-	list_del(&page->lru);
-	zone->free_area[order].nr_free--;
-	rmv_page_order(page);
+
+	del_page_from_free_area(page, area, mt);
 
 	/*
 	 * Set the pageblock if the isolated page is at least half of a
@@ -3265,13 +3248,13 @@  bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
 			continue;
 
 		for (mt = 0; mt < MIGRATE_PCPTYPES; mt++) {
-			if (!list_empty(&area->free_list[mt]))
+			if (!free_area_empty(area, mt))
 				return true;
 		}
 
 #ifdef CONFIG_CMA
 		if ((alloc_flags & ALLOC_CMA) &&
-		    !list_empty(&area->free_list[MIGRATE_CMA])) {
+		    !free_area_empty(area, MIGRATE_CMA)) {
 			return true;
 		}
 #endif
@@ -5173,7 +5156,7 @@  void show_free_areas(unsigned int filter, nodemask_t *nodemask)
 
 			types[order] = 0;
 			for (type = 0; type < MIGRATE_TYPES; type++) {
-				if (!list_empty(&area->free_list[type]))
+				if (!free_area_empty(area, type))
 					types[order] |= 1 << type;
 			}
 		}
@@ -8318,6 +8301,9 @@  __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
 	spin_lock_irqsave(&zone->lock, flags);
 	pfn = start_pfn;
 	while (pfn < end_pfn) {
+		struct free_area *area;
+		int mt;
+
 		if (!pfn_valid(pfn)) {
 			pfn++;
 			continue;
@@ -8336,13 +8322,13 @@  __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
 		BUG_ON(page_count(page));
 		BUG_ON(!PageBuddy(page));
 		order = page_order(page);
+		area = &zone->free_area[order];
 #ifdef CONFIG_DEBUG_VM
 		pr_info("remove from free list %lx %d %lx\n",
 			pfn, 1 << order, end_pfn);
 #endif
-		list_del(&page->lru);
-		rmv_page_order(page);
-		zone->free_area[order].nr_free--;
+		mt = get_pageblock_migratetype(page);
+		del_page_from_free_area(page, area, mt);
 		for (i = 0; i < (1 << order); i++)
 			SetPageReserved((page+i));
 		pfn += (1 << order);