+ mm-zblock-use-vmalloc-for-page-allocations.patch added to mm-new branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/zblock: use vmalloc for page allocations
has been added to the -mm mm-new branch.  Its filename is
     mm-zblock-use-vmalloc-for-page-allocations.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-zblock-use-vmalloc-for-page-allocations.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

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branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: Igor Belousov <igor.b@beldev.am>
Subject: mm/zblock: use vmalloc for page allocations
Date: Fri, 2 May 2025 10:01:56 +0200

Use vmalloc for page allocations for zblock blocks to avoid extra pressure
on the memmory subsystem with multiple higher order allocations.

While at it, introduce a module parameter to opportunistically allocate
pages of lower orders via try_page_alloc() for faster allocations whenever
possible.

Since vmalloc works fine with non-power of 2 numbers of pages, rewrite the
block size tables to use that opportunity.

Link: https://lkml.kernel.org/r/20250502080156.1672957-1-vitaly.wool@konsulko.se
Signed-off-by: Igor Belousov <igor.b@beldev.am>
Signed-off-by: Vitaly Wool <vitaly.wool@konsulko.se>
Cc: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Yosry Ahmed <yosry.ahmed@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/zblock.c |  101 ++++++++++++++++++++++-----------
 mm/zblock.h |  153 ++++++++++++++++++++++++++++----------------------
 2 files changed, 156 insertions(+), 98 deletions(-)

--- a/mm/zblock.c~mm-zblock-use-vmalloc-for-page-allocations
+++ a/mm/zblock.c
@@ -24,12 +24,17 @@
 #include <linux/preempt.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
+#include <linux/vmalloc.h>
 #include <linux/zpool.h>
 #include "zblock.h"
 
 static struct rb_root block_desc_tree = RB_ROOT;
 static struct dentry *zblock_debugfs_root;
 
+/* allocate order 0 blocks using vmalloc? <-- disabled by default */
+static bool vmalloc_small_blocks;
+module_param_named(vmalloc_small_blocks, vmalloc_small_blocks, bool, 0644);
+
 /* Encode handle of a particular slot in the pool using metadata */
 static inline unsigned long metadata_to_handle(struct zblock_block *block,
 				unsigned int block_type, unsigned int slot)
@@ -56,13 +61,14 @@ static inline struct zblock_block *find_
 	struct list_head *l = &b->active_list;
 	unsigned int slot;
 
-	if (!list_empty(l)) {
+	spin_lock(&b->lock);
+	if (likely(!list_empty(l))) {
 		struct zblock_block *z = list_first_entry(l, typeof(*z), link);
 
 		if (--z->free_slots == 0)
-			list_move(&z->link, &b->full_list);
+			__list_del_clearprev(&z->link);
 		/*
-		 * There is a slot in the block and we just made sure it would
+		 * There is a slot in the block and we just made sure it will
 		 * remain.
 		 * Find that slot and set the busy bit.
 		 */
@@ -74,31 +80,57 @@ static inline struct zblock_block *find_
 					slot)) {
 			if (!test_and_set_bit(slot, z->slot_info))
 				break;
-			barrier();
 		}
+		spin_unlock(&b->lock);
 
-		WARN_ON(slot >= block_desc[block_type].slots_per_block);
 		*handle = metadata_to_handle(z, block_type, slot);
 		return z;
 	}
+	spin_unlock(&b->lock);
 	return NULL;
 }
 
+static inline int zblock_get_order(unsigned int num_pages)
+{
+	switch (num_pages) {
+	case 1:
+	case 2:
+		return num_pages - 1;
+	case 4:
+		return 2;
+	default:
+		break;
+	}
+	return -1;
+}
 /*
  * allocate new block and add it to corresponding block list
  */
 static struct zblock_block *alloc_block(struct zblock_pool *pool,
 					int block_type, gfp_t gfp,
-					unsigned long *handle)
+					unsigned long *handle,
+					unsigned int nid)
 {
+	struct block_list *block_list = &pool->block_lists[block_type];
+	unsigned int num_pages = block_desc[block_type].num_pages;
 	struct zblock_block *block;
-	struct block_list *block_list;
+	struct page *page = NULL;
 
-	block = (void *)__get_free_pages(gfp, block_desc[block_type].order);
-	if (!block)
-		return NULL;
+	if (!vmalloc_small_blocks && zblock_get_order(num_pages) >= 0) {
+		page = try_alloc_pages(nid, zblock_get_order(num_pages));
+		if (page) {
+			page->private = PAGE_SMALL_BLOCK;
+			block = page_address(page);
+		}
+	}
+	if (!page) {
+		block = __vmalloc_node(PAGE_SIZE * num_pages, PAGE_SIZE, gfp, nid, NULL);
+		if (!block)
+			return NULL;
 
-	block_list = &pool->block_lists[block_type];
+		page = vmalloc_to_page(block);
+		page->private = 0;
+	}
 
 	/* init block data  */
 	block->free_slots = block_desc[block_type].slots_per_block - 1;
@@ -122,8 +154,8 @@ static int zblock_blocks_show(struct seq
 		struct block_list *block_list = &pool->block_lists[i];
 
 		seq_printf(s, "%d: %ld blocks of %d pages (total %ld pages)\n",
-			i, block_list->block_count, 1 << block_desc[i].order,
-			block_list->block_count << block_desc[i].order);
+			i, block_list->block_count, block_desc[i].num_pages,
+			block_list->block_count * block_desc[i].num_pages);
 	}
 	return 0;
 }
@@ -142,19 +174,17 @@ DEFINE_SHOW_ATTRIBUTE(zblock_blocks);
  */
 static struct zblock_pool *zblock_create_pool(gfp_t gfp)
 {
-	struct zblock_pool *pool;
-	struct block_list *block_list;
+	struct zblock_pool *pool = kmalloc(sizeof(struct zblock_pool), gfp);
 	int i;
 
-	pool = kmalloc(sizeof(struct zblock_pool), gfp);
 	if (!pool)
 		return NULL;
 
 	/* init each block list */
 	for (i = 0; i < ARRAY_SIZE(block_desc); i++) {
-		block_list = &pool->block_lists[i];
+		struct block_list *block_list = &pool->block_lists[i];
+
 		spin_lock_init(&block_list->lock);
-		INIT_LIST_HEAD(&block_list->full_list);
 		INIT_LIST_HEAD(&block_list->active_list);
 		block_list->block_count = 0;
 	}
@@ -187,7 +217,7 @@ static void zblock_destroy_pool(struct z
  * a new slot.
  */
 static int zblock_alloc(struct zblock_pool *pool, size_t size, gfp_t gfp,
-			unsigned long *handle)
+			unsigned long *handle, unsigned int nid)
 {
 	int block_type = -1;
 	struct zblock_block *block;
@@ -196,7 +226,7 @@ static int zblock_alloc(struct zblock_po
 	if (!size)
 		return -EINVAL;
 
-	if (size > PAGE_SIZE)
+	if (size > block_desc[ARRAY_SIZE(block_desc) - 1].slot_size)
 		return -ENOSPC;
 
 	/* find basic block type with suitable slot size */
@@ -220,19 +250,15 @@ static int zblock_alloc(struct zblock_po
 	}
 	if (WARN_ON(block_type < 0))
 		return -EINVAL;
-	if (block_type >= ARRAY_SIZE(block_desc))
-		return -ENOSPC;
 
 	block_list = &pool->block_lists[block_type];
 
-	spin_lock(&block_list->lock);
 	block = find_and_claim_block(block_list, block_type, handle);
-	spin_unlock(&block_list->lock);
 	if (block)
 		return 0;
 
 	/* not found block with free slots try to allocate new empty block */
-	block = alloc_block(pool, block_type, gfp & ~(__GFP_MOVABLE | __GFP_HIGHMEM), handle);
+	block = alloc_block(pool, block_type, gfp, handle, nid);
 	return block ? 0 : -ENOMEM;
 }
 
@@ -251,17 +277,25 @@ static void zblock_free(struct zblock_po
 	block = handle_to_metadata(handle, &block_type, &slot);
 	block_list = &pool->block_lists[block_type];
 
+	/* clear bit early, this will shorten the search */
+	clear_bit(slot, block->slot_info);
+
 	spin_lock(&block_list->lock);
-	/* if all slots in block are empty delete whole block */
+	/* if all slots in block are empty delete the whole block */
 	if (++block->free_slots == block_desc[block_type].slots_per_block) {
+		struct page *page = vmalloc_to_page(block);
+		int num_pages = block_desc[block_type].num_pages;
+
 		block_list->block_count--;
-		list_del(&block->link);
+		__list_del_clearprev(&block->link);
 		spin_unlock(&block_list->lock);
-		free_pages((unsigned long)block, block_desc[block_type].order);
+		if (page->private & PAGE_SMALL_BLOCK)
+			__free_pages(page, zblock_get_order(num_pages));
+		else
+			vfree(block);
 		return;
 	} else if (block->free_slots == 1)
-		list_move_tail(&block->link, &block_list->active_list);
-	clear_bit(slot, block->slot_info);
+		list_add(&block->link, &block_list->active_list);
 	spin_unlock(&block_list->lock);
 }
 
@@ -329,7 +363,7 @@ static u64 zblock_get_total_pages(struct
 
 	total_size = 0;
 	for (i = 0; i < ARRAY_SIZE(block_desc); i++)
-		total_size += pool->block_lists[i].block_count << block_desc[i].order;
+		total_size += pool->block_lists[i].block_count * block_desc[i].num_pages;
 
 	return total_size;
 }
@@ -351,7 +385,7 @@ static void zblock_zpool_destroy(void *p
 static int zblock_zpool_malloc(void *pool, size_t size, gfp_t gfp,
 			unsigned long *handle, const int nid)
 {
-	return zblock_alloc(pool, size, gfp, handle);
+	return zblock_alloc(pool, size, gfp, handle, nid);
 }
 
 static void zblock_zpool_free(void *pool, unsigned long handle)
@@ -407,6 +441,7 @@ static int __init create_rbtree(void)
 {
 	int i;
 
+	BUILD_BUG_ON(ARRAY_SIZE(block_desc) > MAX_TABLE_SIZE);
 	for (i = 0; i < ARRAY_SIZE(block_desc); i++) {
 		struct block_desc_node *block_node = kmalloc(sizeof(*block_node),
 							GFP_KERNEL);
@@ -425,7 +460,7 @@ static int __init create_rbtree(void)
 		block_node->this_slot_size = block_desc[i].slot_size;
 		block_node->block_idx = i;
 		if (i == ARRAY_SIZE(block_desc) - 1)
-			block_node->next_slot_size = PAGE_SIZE;
+			block_node->next_slot_size = PAGE_SIZE * 2;
 		else
 			block_node->next_slot_size = block_desc[i+1].slot_size;
 		while (*new) {
--- a/mm/zblock.h~mm-zblock-use-vmalloc-for-page-allocations
+++ a/mm/zblock.h
@@ -10,13 +10,11 @@
 #include <linux/rbtree.h>
 #include <linux/types.h>
 
-#define SLOT_FREE 0
-#define BIT_SLOT_OCCUPIED 0
-#define BIT_SLOT_MAPPED 1
+#define PAGE_SMALL_BLOCK	1
 
 #if PAGE_SIZE == 0x1000
-/* max 128 slots per block, max table size 32 */
-#define SLOT_BITS 7
+/* max 64 slots per block, max table size 64 */
+#define SLOT_BITS 6
 #elif PAGE_SIZE == 0x4000
 /* max 256 slots per block, max table size 64 */
 #define SLOT_BITS 8
@@ -25,24 +23,26 @@
 #define SLOT_BITS 8
 #endif
 
+#define MAX_TABLE_SIZE (1 << (PAGE_SHIFT - SLOT_BITS))
+
 #define MAX_SLOTS (1 << SLOT_BITS)
 #define SLOT_MASK ((0x1UL << SLOT_BITS) - 1)
 
 #define ZBLOCK_HEADER_SIZE	round_up(sizeof(struct zblock_block), sizeof(long))
-#define BLOCK_DATA_SIZE(order) ((PAGE_SIZE << order) - ZBLOCK_HEADER_SIZE)
-#define SLOT_SIZE(nslots, order) (round_down((BLOCK_DATA_SIZE(order) / nslots), sizeof(long)))
+#define BLOCK_DATA_SIZE(num) ((PAGE_SIZE * (num)) - ZBLOCK_HEADER_SIZE)
+#define SLOT_SIZE(nslots, num) (round_down((BLOCK_DATA_SIZE(num) / nslots), sizeof(long)))
 
 /**
  * struct zblock_block - block metadata
- * Block consists of several (1/2/4/8) pages and contains fixed
+ * Block consists of several pages and contains fixed
  * integer number of slots for allocating compressed pages.
  *
  * free_slots:	number of free slots in the block
  * slot_info:	contains data about free/occupied slots
  */
 struct zblock_block {
-	struct list_head link;
 	DECLARE_BITMAP(slot_info, 1 << SLOT_BITS);
+	struct list_head link;
 	u32 free_slots;
 };
 
@@ -54,12 +54,12 @@ struct zblock_block {
  *
  * slot_size:		size of slot for this list
  * slots_per_block:	number of slots per block for this list
- * order:		order for __get_free_pages
+ * num_pages:		number of pages per block
  */
 struct block_desc {
 	unsigned int slot_size;
 	unsigned short slots_per_block;
-	unsigned short order;
+	unsigned short num_pages;
 };
 
 struct block_desc_node {
@@ -71,78 +71,103 @@ struct block_desc_node {
 
 static const struct block_desc block_desc[] = {
 #if PAGE_SIZE == 0x1000
-	{ SLOT_SIZE(63, 0), 63, 0 },
-	{ SLOT_SIZE(32, 0), 32, 0 },
-	{ SLOT_SIZE(21, 0), 21, 0 },
-	{ SLOT_SIZE(15, 0), 15, 0 },
-	{ SLOT_SIZE(12, 0), 12, 0 },
-	{ SLOT_SIZE(10, 0), 10, 0 },
-	{ SLOT_SIZE(9, 0), 9, 0 },
-	{ SLOT_SIZE(8, 0), 8, 0 },
-	{ SLOT_SIZE(29, 2), 29, 2 },
-	{ SLOT_SIZE(13, 1), 13, 1 },
-	{ SLOT_SIZE(6, 0), 6, 0 },
-	{ SLOT_SIZE(11, 1), 11, 1 },
-	{ SLOT_SIZE(5, 0), 5, 0 },
-	{ SLOT_SIZE(9, 1), 9, 1 },
-	{ SLOT_SIZE(8, 1), 8, 1 },
-	{ SLOT_SIZE(29, 3), 29, 3 },
+	{ SLOT_SIZE(28, 1), 28, 1 },
+	{ SLOT_SIZE(18, 1), 18, 1 },
+	{ SLOT_SIZE(12, 1), 12, 1 },
+	{ SLOT_SIZE(10, 1), 10, 1 },
+	{ SLOT_SIZE(17, 2), 17, 2 },
+	{ SLOT_SIZE(15, 2), 15, 2 },
 	{ SLOT_SIZE(13, 2), 13, 2 },
-	{ SLOT_SIZE(12, 2), 12, 2 },
+	{ SLOT_SIZE(6, 1), 6, 1 },
 	{ SLOT_SIZE(11, 2), 11, 2 },
-	{ SLOT_SIZE(10, 2), 10, 2 },
+	{ SLOT_SIZE(5, 1), 5, 1 },
+	{ SLOT_SIZE(19, 4), 19, 4 },
 	{ SLOT_SIZE(9, 2), 9, 2 },
-	{ SLOT_SIZE(17, 3), 17, 3 },
-	{ SLOT_SIZE(8, 2), 8, 2 },
-	{ SLOT_SIZE(15, 3), 15, 3 },
-	{ SLOT_SIZE(14, 3), 14, 3 },
-	{ SLOT_SIZE(13, 3), 13, 3 },
-	{ SLOT_SIZE(6, 2), 6, 2 },
+	{ SLOT_SIZE(17, 4), 17, 4 },
+	{ SLOT_SIZE(4, 1), 4, 1 },
+	{ SLOT_SIZE(23, 6), 23, 6 },
 	{ SLOT_SIZE(11, 3), 11, 3 },
+	{ SLOT_SIZE(7, 2), 7, 2 },
 	{ SLOT_SIZE(10, 3), 10, 3 },
-	{ SLOT_SIZE(9, 3), 9, 3 },
-	{ SLOT_SIZE(4, 2), 4, 2 },
+	{ SLOT_SIZE(19, 6), 19, 6 },
+	{ SLOT_SIZE(6, 2), 6, 2 },
+	{ SLOT_SIZE(14, 5), 14, 5 },
+	{ SLOT_SIZE(8, 3), 8, 3 },
+	{ SLOT_SIZE(5, 2), 5, 2 },
+	{ SLOT_SIZE(12, 5), 12, 5 },
+	{ SLOT_SIZE(9, 4), 9, 4 },
+	{ SLOT_SIZE(15, 7), 15, 7 },
+	{ SLOT_SIZE(2, 1), 2, 1 },
+	{ SLOT_SIZE(15, 8), 15, 8 },
+	{ SLOT_SIZE(9, 5), 9, 5 },
+	{ SLOT_SIZE(12, 7), 12, 7 },
+	{ SLOT_SIZE(13, 8), 13, 8 },
+	{ SLOT_SIZE(6, 4), 6, 4 },
+	{ SLOT_SIZE(11, 8), 11, 8 },
+	{ SLOT_SIZE(9, 7), 9, 7 },
+	{ SLOT_SIZE(6, 5), 6, 5 },
+	{ SLOT_SIZE(9, 8), 9, 8 },
+	{ SLOT_SIZE(4, 4), 4, 4 },
 #else
-	{ SLOT_SIZE(255, 0), 255, 0 },
-	{ SLOT_SIZE(185, 0), 185, 0 },
-	{ SLOT_SIZE(145, 0), 145, 0 },
-	{ SLOT_SIZE(113, 0), 113, 0 },
-	{ SLOT_SIZE(92, 0), 92, 0 },
-	{ SLOT_SIZE(75, 0), 75, 0 },
-	{ SLOT_SIZE(60, 0), 60, 0 },
-	{ SLOT_SIZE(51, 0), 51, 0 },
-	{ SLOT_SIZE(43, 0), 43, 0 },
-	{ SLOT_SIZE(37, 0), 37, 0 },
-	{ SLOT_SIZE(32, 0), 32, 0 },
-	{ SLOT_SIZE(27, 0), 27, 0 },
-	{ SLOT_SIZE(23, 0), 23, 0 },
-	{ SLOT_SIZE(19, 0), 19, 0 },
-	{ SLOT_SIZE(17, 0), 17, 0 },
-	{ SLOT_SIZE(15, 0), 15, 0 },
-	{ SLOT_SIZE(13, 0), 13, 0 },
-	{ SLOT_SIZE(11, 0), 11, 0 },
-	{ SLOT_SIZE(10, 0), 10, 0 },
-	{ SLOT_SIZE(9, 0), 9, 0 },
-	{ SLOT_SIZE(8, 0), 8, 0 },
-	{ SLOT_SIZE(15, 1), 15, 1 },
-	{ SLOT_SIZE(14, 1), 14, 1 },
-	{ SLOT_SIZE(13, 1), 13, 1 },
+	{ SLOT_SIZE(185, 1), 185, 1 },
+	{ SLOT_SIZE(113, 1), 113, 1 },
+	{ SLOT_SIZE(86, 1), 86, 1 },
+	{ SLOT_SIZE(72, 1), 72, 1 },
+	{ SLOT_SIZE(58, 1), 58, 1 },
+	{ SLOT_SIZE(49, 1), 49, 1 },
+	{ SLOT_SIZE(42, 1), 42, 1 },
+	{ SLOT_SIZE(37, 1), 37, 1 },
+	{ SLOT_SIZE(33, 1), 33, 1 },
+	{ SLOT_SIZE(59, 2), 59, 2 },
+	{ SLOT_SIZE(27, 1), 27, 1 },
+	{ SLOT_SIZE(25, 1), 25, 1 },
+	{ SLOT_SIZE(23, 1), 23, 1 },
+	{ SLOT_SIZE(21, 1), 21, 1 },
+	{ SLOT_SIZE(39, 2), 39, 2 },
+	{ SLOT_SIZE(37, 2), 37, 2 },
+	{ SLOT_SIZE(35, 2), 35, 2 },
+	{ SLOT_SIZE(33, 2), 33, 2 },
+	{ SLOT_SIZE(31, 2), 31, 2 },
+	{ SLOT_SIZE(29, 2), 29, 2 },
+	{ SLOT_SIZE(27, 2), 27, 2 },
+	{ SLOT_SIZE(25, 2), 25, 2 },
 	{ SLOT_SIZE(12, 1), 12, 1 },
 	{ SLOT_SIZE(11, 1), 11, 1 },
+	{ SLOT_SIZE(21, 2), 21, 2 },
 	{ SLOT_SIZE(10, 1), 10, 1 },
+	{ SLOT_SIZE(19, 2), 19, 2 },
 	{ SLOT_SIZE(9, 1), 9, 1 },
+	{ SLOT_SIZE(17, 2), 17, 2 },
 	{ SLOT_SIZE(8, 1), 8, 1 },
 	{ SLOT_SIZE(15, 2), 15, 2 },
 	{ SLOT_SIZE(14, 2), 14, 2 },
 	{ SLOT_SIZE(13, 2), 13, 2 },
 	{ SLOT_SIZE(12, 2), 12, 2 },
+	{ SLOT_SIZE(23, 4), 23, 4 },
 	{ SLOT_SIZE(11, 2), 11, 2 },
+	{ SLOT_SIZE(21, 4), 21, 4 },
 	{ SLOT_SIZE(10, 2), 10, 2 },
+	{ SLOT_SIZE(19, 4), 19, 4 },
 	{ SLOT_SIZE(9, 2), 9, 2 },
+	{ SLOT_SIZE(17, 4), 17, 4 },
 	{ SLOT_SIZE(8, 2), 8, 2 },
-	{ SLOT_SIZE(7, 2), 7, 2 },
-	{ SLOT_SIZE(6, 2), 6, 2 },
+	{ SLOT_SIZE(15, 4), 15, 4 },
+	{ SLOT_SIZE(14, 4), 14, 4 },
+	{ SLOT_SIZE(10, 3), 10, 3 },
+	{ SLOT_SIZE(16, 5), 16, 5 },
+	{ SLOT_SIZE(12, 4), 12, 4 },
+	{ SLOT_SIZE(11, 4), 11, 4 },
+	{ SLOT_SIZE(8, 3), 8, 3 },
 	{ SLOT_SIZE(5, 2), 5, 2 },
+	{ SLOT_SIZE(7, 3), 7, 3 },
+	{ SLOT_SIZE(11, 5), 11, 5 },
+	{ SLOT_SIZE(4, 2), 4, 2 },
+	{ SLOT_SIZE(9, 5), 9, 5 },
+	{ SLOT_SIZE(8, 5), 8, 5 },
+	{ SLOT_SIZE(3, 2), 3, 2 },
+	{ SLOT_SIZE(4, 3), 4, 3 },
+	{ SLOT_SIZE(7, 6), 7, 6 },
+	{ SLOT_SIZE(4, 4), 4, 4 },
 #endif /* PAGE_SIZE */
 };
 
@@ -150,13 +175,11 @@ static const struct block_desc block_des
  * struct block_list - stores metadata of particular list
  * lock:		protects the list of blocks
  * active_list:		linked list of active (non-full) blocks
- * full_list:		linked list of full blocks
  * block_count:		total number of blocks in the list
  */
 struct block_list {
 	spinlock_t lock;
 	struct list_head active_list;
-	struct list_head full_list;
 	unsigned long block_count;
 };
 
_

Patches currently in -mm which might be from igor.b@beldev.am are

mm-zblock-add-debugfs.patch
mm-zblock-avoid-failing-the-build.patch
mm-zblock-use-vmalloc-for-page-allocations.patch