On Sun, Nov 19, 2023 at 06:21:36PM +0300, Kirill A. Shutemov wrote:
> > Oh well. Now we have places with 'MAX_ORDER + 1' instead of 'MAX_ORDER
> > - 1'. I'm not seeing that it's a win, and I do think "semantic change
> > after 24 years" is a loss and is going to cause problems.
>
> I think it worth introducing NR_ORDERS for MAX_ORDER + 1 to define how
> many page orders page allocator supports. Sounds good?
Something like this:
>From 124d43bddb274e97de0ca8b125c0a41030b3ac57 Mon Sep 17 00:00:00 2001
From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Date: Mon, 20 Nov 2023 15:14:29 +0300
Subject: [PATCH] MM: Introduce NR_ORDERS
NR_ORDERS defines the number of page orders supported by the page
allocator, ranging from 0 to MAX_ORDER, MAX_ORDER + 1 in total.
NR_ORDERS assists in defining arrays of page orders and allows for more
natural iteration over them.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
.../admin-guide/kdump/vmcoreinfo.rst | 4 ++--
arch/arm64/kvm/hyp/include/nvhe/gfp.h | 2 +-
arch/sparc/kernel/traps_64.c | 2 +-
drivers/gpu/drm/ttm/tests/ttm_device_test.c | 2 +-
drivers/gpu/drm/ttm/ttm_pool.c | 20 +++++++++----------
include/drm/ttm/ttm_pool.h | 2 +-
include/linux/mmzone.h | 6 ++++--
kernel/crash_core.c | 2 +-
lib/test_meminit.c | 2 +-
mm/compaction.c | 2 +-
mm/kmsan/init.c | 2 +-
mm/page_alloc.c | 13 ++++++------
mm/page_reporting.c | 2 +-
mm/show_mem.c | 8 ++++----
mm/vmstat.c | 12 +++++------
15 files changed, 41 insertions(+), 40 deletions(-)
diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst
index 78e4d2e7ba14..e32d3214b4a0 100644
--- a/Documentation/admin-guide/kdump/vmcoreinfo.rst
+++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst
@@ -172,7 +172,7 @@ variables.
Offset of the free_list's member. This value is used to compute the number
of free pages.
-Each zone has a free_area structure array called free_area[MAX_ORDER + 1].
+Each zone has a free_area structure array called free_area[NR_ORDERS].
The free_list represents a linked list of free page blocks.
(list_head, next|prev)
@@ -189,7 +189,7 @@ Offsets of the vmap_area's members. They carry vmalloc-specific
information. Makedumpfile gets the start address of the vmalloc region
from this.
-(zone.free_area, MAX_ORDER + 1)
+(zone.free_area, NR_ORDERS)
-------------------------------
Free areas descriptor. User-space tools use this value to iterate the
diff --git a/arch/arm64/kvm/hyp/include/nvhe/gfp.h b/arch/arm64/kvm/hyp/include/nvhe/gfp.h
index fe5472a184a3..47305934b7ff 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/gfp.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/gfp.h
@@ -16,7 +16,7 @@ struct hyp_pool {
* API at EL2.
*/
hyp_spinlock_t lock;
- struct list_head free_area[MAX_ORDER + 1];
+ struct list_head free_area[NR_ORDERS];
phys_addr_t range_start;
phys_addr_t range_end;
unsigned short max_order;
diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c
index 08ffd17d5ec3..c127eab8283f 100644
--- a/arch/sparc/kernel/traps_64.c
+++ b/arch/sparc/kernel/traps_64.c
@@ -897,7 +897,7 @@ void __init cheetah_ecache_flush_init(void)
/* Now allocate error trap reporting scoreboard. */
sz = NR_CPUS * (2 * sizeof(struct cheetah_err_info));
- for (order = 0; order <= MAX_ORDER; order++) {
+ for (order = 0; order < NR_ORDERS; order++) {
if ((PAGE_SIZE << order) >= sz)
break;
}
diff --git a/drivers/gpu/drm/ttm/tests/ttm_device_test.c b/drivers/gpu/drm/ttm/tests/ttm_device_test.c
index b1b423b68cdf..f7e8c12ec696 100644
--- a/drivers/gpu/drm/ttm/tests/ttm_device_test.c
+++ b/drivers/gpu/drm/ttm/tests/ttm_device_test.c
@@ -175,7 +175,7 @@ static void ttm_device_init_pools(struct kunit *test)
if (params->pools_init_expected) {
for (int i = 0; i < TTM_NUM_CACHING_TYPES; ++i) {
- for (int j = 0; j <= MAX_ORDER; ++j) {
+ for (int j = 0; j < NR_ORDERS; ++j) {
pt = pool->caching[i].orders[j];
KUNIT_EXPECT_PTR_EQ(test, pt.pool, pool);
KUNIT_EXPECT_EQ(test, pt.caching, i);
diff --git a/drivers/gpu/drm/ttm/ttm_pool.c b/drivers/gpu/drm/ttm/ttm_pool.c
index fe610a3cace0..701362f015ec 100644
--- a/drivers/gpu/drm/ttm/ttm_pool.c
+++ b/drivers/gpu/drm/ttm/ttm_pool.c
@@ -65,11 +65,11 @@ module_param(page_pool_size, ulong, 0644);
static atomic_long_t allocated_pages;
-static struct ttm_pool_type global_write_combined[MAX_ORDER + 1];
-static struct ttm_pool_type global_uncached[MAX_ORDER + 1];
+static struct ttm_pool_type global_write_combined[NR_ORDERS];
+static struct ttm_pool_type global_uncached[NR_ORDERS];
-static struct ttm_pool_type global_dma32_write_combined[MAX_ORDER + 1];
-static struct ttm_pool_type global_dma32_uncached[MAX_ORDER + 1];
+static struct ttm_pool_type global_dma32_write_combined[NR_ORDERS];
+static struct ttm_pool_type global_dma32_uncached[NR_ORDERS];
static spinlock_t shrinker_lock;
static struct list_head shrinker_list;
@@ -568,7 +568,7 @@ void ttm_pool_init(struct ttm_pool *pool, struct device *dev,
if (use_dma_alloc || nid != NUMA_NO_NODE) {
for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i)
- for (j = 0; j <= MAX_ORDER; ++j)
+ for (j = 0; j < NR_ORDERS; ++j)
ttm_pool_type_init(&pool->caching[i].orders[j],
pool, i, j);
}
@@ -601,7 +601,7 @@ void ttm_pool_fini(struct ttm_pool *pool)
if (pool->use_dma_alloc || pool->nid != NUMA_NO_NODE) {
for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i)
- for (j = 0; j <= MAX_ORDER; ++j)
+ for (j = 0; j < NR_ORDERS; ++j)
ttm_pool_type_fini(&pool->caching[i].orders[j]);
}
@@ -656,7 +656,7 @@ static void ttm_pool_debugfs_header(struct seq_file *m)
unsigned int i;
seq_puts(m, "\t ");
- for (i = 0; i <= MAX_ORDER; ++i)
+ for (i = 0; i < NR_ORDERS; ++i)
seq_printf(m, " ---%2u---", i);
seq_puts(m, "\n");
}
@@ -667,7 +667,7 @@ static void ttm_pool_debugfs_orders(struct ttm_pool_type *pt,
{
unsigned int i;
- for (i = 0; i <= MAX_ORDER; ++i)
+ for (i = 0; i < NR_ORDERS; ++i)
seq_printf(m, " %8u", ttm_pool_type_count(&pt[i]));
seq_puts(m, "\n");
}
@@ -776,7 +776,7 @@ int ttm_pool_mgr_init(unsigned long num_pages)
spin_lock_init(&shrinker_lock);
INIT_LIST_HEAD(&shrinker_list);
- for (i = 0; i <= MAX_ORDER; ++i) {
+ for (i = 0; i < NR_ORDERS; ++i) {
ttm_pool_type_init(&global_write_combined[i], NULL,
ttm_write_combined, i);
ttm_pool_type_init(&global_uncached[i], NULL, ttm_uncached, i);
@@ -816,7 +816,7 @@ void ttm_pool_mgr_fini(void)
{
unsigned int i;
- for (i = 0; i <= MAX_ORDER; ++i) {
+ for (i = 0; i < NR_ORDERS; ++i) {
ttm_pool_type_fini(&global_write_combined[i]);
ttm_pool_type_fini(&global_uncached[i]);
diff --git a/include/drm/ttm/ttm_pool.h b/include/drm/ttm/ttm_pool.h
index 30a347e5aa11..8e54bf456981 100644
--- a/include/drm/ttm/ttm_pool.h
+++ b/include/drm/ttm/ttm_pool.h
@@ -74,7 +74,7 @@ struct ttm_pool {
bool use_dma32;
struct {
- struct ttm_pool_type orders[MAX_ORDER + 1];
+ struct ttm_pool_type orders[NR_ORDERS];
} caching[TTM_NUM_CACHING_TYPES];
};
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 3c25226beeed..9f457ebdaa9a 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -34,6 +34,8 @@
#define IS_MAX_ORDER_ALIGNED(pfn) IS_ALIGNED(pfn, MAX_ORDER_NR_PAGES)
+#define NR_ORDERS (MAX_ORDER + 1)
+
/*
* PAGE_ALLOC_COSTLY_ORDER is the order at which allocations are deemed
* costly to service. That is between allocation orders which should
@@ -95,7 +97,7 @@ static inline bool migratetype_is_mergeable(int mt)
}
#define for_each_migratetype_order(order, type) \
- for (order = 0; order <= MAX_ORDER; order++) \
+ for (order = 0; order < NR_ORDERS; order++) \
for (type = 0; type < MIGRATE_TYPES; type++)
extern int page_group_by_mobility_disabled;
@@ -943,7 +945,7 @@ struct zone {
CACHELINE_PADDING(_pad1_);
/* free areas of different sizes */
- struct free_area free_area[MAX_ORDER + 1];
+ struct free_area free_area[NR_ORDERS];
#ifdef CONFIG_UNACCEPTED_MEMORY
/* Pages to be accepted. All pages on the list are MAX_ORDER */
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index efe87d501c8c..acd7201b4385 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -802,7 +802,7 @@ static int __init crash_save_vmcoreinfo_init(void)
VMCOREINFO_OFFSET(list_head, prev);
VMCOREINFO_OFFSET(vmap_area, va_start);
VMCOREINFO_OFFSET(vmap_area, list);
- VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER + 1);
+ VMCOREINFO_LENGTH(zone.free_area, NR_ORDERS);
log_buf_vmcoreinfo_setup();
VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);
VMCOREINFO_NUMBER(NR_FREE_PAGES);
diff --git a/lib/test_meminit.c b/lib/test_meminit.c
index 0ae35223d773..32f44bd61422 100644
--- a/lib/test_meminit.c
+++ b/lib/test_meminit.c
@@ -93,7 +93,7 @@ static int __init test_pages(int *total_failures)
int failures = 0, num_tests = 0;
int i;
- for (i = 0; i <= MAX_ORDER; i++)
+ for (i = 0; i < NR_ORDERS; i++)
num_tests += do_alloc_pages_order(i, &failures);
REPORT_FAILURES_IN_FN();
diff --git a/mm/compaction.c b/mm/compaction.c
index 01ba298739dd..f819c51d856f 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -2226,7 +2226,7 @@ static enum compact_result __compact_finished(struct compact_control *cc)
/* Direct compactor: Is a suitable page free? */
ret = COMPACT_NO_SUITABLE_PAGE;
- for (order = cc->order; order <= MAX_ORDER; order++) {
+ for (order = cc->order; order < NR_ORDERS; order++) {
struct free_area *area = &cc->zone->free_area[order];
bool can_steal;
diff --git a/mm/kmsan/init.c b/mm/kmsan/init.c
index ffedf4dbc49d..8aefbcd997f3 100644
--- a/mm/kmsan/init.c
+++ b/mm/kmsan/init.c
@@ -96,7 +96,7 @@ void __init kmsan_init_shadow(void)
struct metadata_page_pair {
struct page *shadow, *origin;
};
-static struct metadata_page_pair held_back[MAX_ORDER + 1] __initdata;
+static struct metadata_page_pair held_back[NR_ORDERS] __initdata;
/*
* Eager metadata allocation. When the memblock allocator is freeing pages to
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 733732e7e0ba..0bac7794d33e 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1571,7 +1571,7 @@ struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
struct page *page;
/* Find a page of the appropriate size in the preferred list */
- for (current_order = order; current_order <= MAX_ORDER; ++current_order) {
+ for (current_order = order; current_order < NR_ORDERS; ++current_order) {
area = &(zone->free_area[current_order]);
page = get_page_from_free_area(area, migratetype);
if (!page)
@@ -1941,7 +1941,7 @@ static bool unreserve_highatomic_pageblock(const struct alloc_context *ac,
continue;
spin_lock_irqsave(&zone->lock, flags);
- for (order = 0; order <= MAX_ORDER; order++) {
+ for (order = 0; order < NR_ORDERS; order++) {
struct free_area *area = &(zone->free_area[order]);
page = get_page_from_free_area(area, MIGRATE_HIGHATOMIC);
@@ -2051,8 +2051,7 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype,
return false;
find_smallest:
- for (current_order = order; current_order <= MAX_ORDER;
- current_order++) {
+ for (current_order = order; current_order < NR_ORDERS; current_order++) {
area = &(zone->free_area[current_order]);
fallback_mt = find_suitable_fallback(area, current_order,
start_migratetype, false, &can_steal);
@@ -3007,7 +3006,7 @@ bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
return true;
/* For a high-order request, check at least one suitable page is free */
- for (o = order; o <= MAX_ORDER; o++) {
+ for (o = order; o < NR_ORDERS; o++) {
struct free_area *area = &z->free_area[o];
int mt;
@@ -6635,7 +6634,7 @@ bool is_free_buddy_page(struct page *page)
unsigned long pfn = page_to_pfn(page);
unsigned int order;
- for (order = 0; order <= MAX_ORDER; order++) {
+ for (order = 0; order < NR_ORDERS; order++) {
struct page *page_head = page - (pfn & ((1 << order) - 1));
if (PageBuddy(page_head) &&
@@ -6690,7 +6689,7 @@ bool take_page_off_buddy(struct page *page)
bool ret = false;
spin_lock_irqsave(&zone->lock, flags);
- for (order = 0; order <= MAX_ORDER; order++) {
+ for (order = 0; order < NR_ORDERS; order++) {
struct page *page_head = page - (pfn & ((1 << order) - 1));
int page_order = buddy_order(page_head);
diff --git a/mm/page_reporting.c b/mm/page_reporting.c
index b021f482a4cb..14c0782a3711 100644
--- a/mm/page_reporting.c
+++ b/mm/page_reporting.c
@@ -276,7 +276,7 @@ page_reporting_process_zone(struct page_reporting_dev_info *prdev,
return err;
/* Process each free list starting from lowest order/mt */
- for (order = page_reporting_order; order <= MAX_ORDER; order++) {
+ for (order = page_reporting_order; order < NR_ORDERS; order++) {
for (mt = 0; mt < MIGRATE_TYPES; mt++) {
/* We do not pull pages from the isolate free list */
if (is_migrate_isolate(mt))
diff --git a/mm/show_mem.c b/mm/show_mem.c
index ba0808d6917f..77fa459962c6 100644
--- a/mm/show_mem.c
+++ b/mm/show_mem.c
@@ -352,8 +352,8 @@ static void show_free_areas(unsigned int filter, nodemask_t *nodemask, int max_z
for_each_populated_zone(zone) {
unsigned int order;
- unsigned long nr[MAX_ORDER + 1], flags, total = 0;
- unsigned char types[MAX_ORDER + 1];
+ unsigned long nr[NR_ORDERS], flags, total = 0;
+ unsigned char types[NR_ORDERS];
if (zone_idx(zone) > max_zone_idx)
continue;
@@ -363,7 +363,7 @@ static void show_free_areas(unsigned int filter, nodemask_t *nodemask, int max_z
printk(KERN_CONT "%s: ", zone->name);
spin_lock_irqsave(&zone->lock, flags);
- for (order = 0; order <= MAX_ORDER; order++) {
+ for (order = 0; order < NR_ORDERS; order++) {
struct free_area *area = &zone->free_area[order];
int type;
@@ -377,7 +377,7 @@ static void show_free_areas(unsigned int filter, nodemask_t *nodemask, int max_z
}
}
spin_unlock_irqrestore(&zone->lock, flags);
- for (order = 0; order <= MAX_ORDER; order++) {
+ for (order = 0; order < NR_ORDERS; order++) {
printk(KERN_CONT "%lu*%lukB ",
nr[order], K(1UL) << order);
if (nr[order])
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 359460deb377..f9ac978ef748 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1059,7 +1059,7 @@ static void fill_contig_page_info(struct zone *zone,
info->free_blocks_total = 0;
info->free_blocks_suitable = 0;
- for (order = 0; order <= MAX_ORDER; order++) {
+ for (order = 0; order < NR_ORDERS; order++) {
unsigned long blocks;
/*
@@ -1475,7 +1475,7 @@ static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
int order;
seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
- for (order = 0; order <= MAX_ORDER; ++order)
+ for (order = 0; order < NR_ORDERS; ++order)
/*
* Access to nr_free is lockless as nr_free is used only for
* printing purposes. Use data_race to avoid KCSAN warning.
@@ -1504,7 +1504,7 @@ static void pagetypeinfo_showfree_print(struct seq_file *m,
pgdat->node_id,
zone->name,
migratetype_names[mtype]);
- for (order = 0; order <= MAX_ORDER; ++order) {
+ for (order = 0; order < NR_ORDERS; ++order) {
unsigned long freecount = 0;
struct free_area *area;
struct list_head *curr;
@@ -1544,7 +1544,7 @@ static void pagetypeinfo_showfree(struct seq_file *m, void *arg)
/* Print header */
seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
- for (order = 0; order <= MAX_ORDER; ++order)
+ for (order = 0; order < NR_ORDERS; ++order)
seq_printf(m, "%6d ", order);
seq_putc(m, '\n');
@@ -2180,7 +2180,7 @@ static void unusable_show_print(struct seq_file *m,
seq_printf(m, "Node %d, zone %8s ",
pgdat->node_id,
zone->name);
- for (order = 0; order <= MAX_ORDER; ++order) {
+ for (order = 0; order < NR_ORDERS; ++order) {
fill_contig_page_info(zone, order, &info);
index = unusable_free_index(order, &info);
seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
@@ -2232,7 +2232,7 @@ static void extfrag_show_print(struct seq_file *m,
seq_printf(m, "Node %d, zone %8s ",
pgdat->node_id,
zone->name);
- for (order = 0; order <= MAX_ORDER; ++order) {
+ for (order = 0; order < NR_ORDERS; ++order) {
fill_contig_page_info(zone, order, &info);
index = __fragmentation_index(order, &info);
seq_printf(m, "%2d.%03d ", index / 1000, index % 1000);
--
2.41.0
--
Kiryl Shutsemau / Kirill A. Shutemov
