[PATCH] mm, show_mem: Remove SHOW_MEM_FILTER_PAGE_COUNT

From: Mel Gorman
Date: Tue Dec 03 2013 - 09:57:36 EST


Commit 4b59e6c4 (mm, show_mem: suppress page counts in non-blockable
contexts) introduced SHOW_MEM_FILTER_PAGE_COUNT to suppress PFN walks
on large memory machines. Commit c78e9363 (mm: do not walk all of system
memory during show_mem) avoided a PFN walk in the generic show_mem helper
which removes the requirement for SHOW_MEM_FILTER_PAGE_COUNT in that case.

This patch removes PFN walkers from the arch-specific implementations that
report on a per-node or per-zone granularity. ARM and unicore32 still do
a PFN walk as they report memory usage on each bank which is a much finer
granularity where the debugging information may still be of use. As the
remaining arches doing PFN walks have relatively small amounts of memory,
this patch simply removes SHOW_MEM_FILTER_PAGE_COUNT.

Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
---
arch/arm/mm/init.c | 3 ---
arch/ia64/mm/contig.c | 68 ------------------------------------------------
arch/ia64/mm/discontig.c | 63 --------------------------------------------
arch/ia64/mm/init.c | 48 ++++++++++++++++++++++++++++++++++
arch/parisc/mm/init.c | 62 ++++++++++++++-----------------------------
arch/unicore32/mm/init.c | 3 ---
include/linux/mm.h | 1 -
lib/show_mem.c | 3 ---
mm/page_alloc.c | 7 -----
9 files changed, 68 insertions(+), 190 deletions(-)

diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 3e8f106..2e71e24 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -92,9 +92,6 @@ void show_mem(unsigned int filter)
printk("Mem-info:\n");
show_free_areas(filter);

- if (filter & SHOW_MEM_FILTER_PAGE_COUNT)
- return;
-
for_each_bank (i, mi) {
struct membank *bank = &mi->bank[i];
unsigned int pfn1, pfn2;
diff --git a/arch/ia64/mm/contig.c b/arch/ia64/mm/contig.c
index da5237d..52715a7 100644
--- a/arch/ia64/mm/contig.c
+++ b/arch/ia64/mm/contig.c
@@ -31,74 +31,6 @@
static unsigned long max_gap;
#endif

-/**
- * show_mem - give short summary of memory stats
- *
- * Shows a simple page count of reserved and used pages in the system.
- * For discontig machines, it does this on a per-pgdat basis.
- */
-void show_mem(unsigned int filter)
-{
- int i, total_reserved = 0;
- int total_shared = 0, total_cached = 0;
- unsigned long total_present = 0;
- pg_data_t *pgdat;
-
- printk(KERN_INFO "Mem-info:\n");
- show_free_areas(filter);
- printk(KERN_INFO "Node memory in pages:\n");
- if (filter & SHOW_MEM_FILTER_PAGE_COUNT)
- return;
- for_each_online_pgdat(pgdat) {
- unsigned long present;
- unsigned long flags;
- int shared = 0, cached = 0, reserved = 0;
- int nid = pgdat->node_id;
-
- if (skip_free_areas_node(filter, nid))
- continue;
- pgdat_resize_lock(pgdat, &flags);
- present = pgdat->node_present_pages;
- for(i = 0; i < pgdat->node_spanned_pages; i++) {
- struct page *page;
- if (unlikely(i % MAX_ORDER_NR_PAGES == 0))
- touch_nmi_watchdog();
- if (pfn_valid(pgdat->node_start_pfn + i))
- page = pfn_to_page(pgdat->node_start_pfn + i);
- else {
-#ifdef CONFIG_VIRTUAL_MEM_MAP
- if (max_gap < LARGE_GAP)
- continue;
-#endif
- i = vmemmap_find_next_valid_pfn(nid, i) - 1;
- continue;
- }
- if (PageReserved(page))
- reserved++;
- else if (PageSwapCache(page))
- cached++;
- else if (page_count(page))
- shared += page_count(page)-1;
- }
- pgdat_resize_unlock(pgdat, &flags);
- total_present += present;
- total_reserved += reserved;
- total_cached += cached;
- total_shared += shared;
- printk(KERN_INFO "Node %4d: RAM: %11ld, rsvd: %8d, "
- "shrd: %10d, swpd: %10d\n", nid,
- present, reserved, shared, cached);
- }
- printk(KERN_INFO "%ld pages of RAM\n", total_present);
- printk(KERN_INFO "%d reserved pages\n", total_reserved);
- printk(KERN_INFO "%d pages shared\n", total_shared);
- printk(KERN_INFO "%d pages swap cached\n", total_cached);
- printk(KERN_INFO "Total of %ld pages in page table cache\n",
- quicklist_total_size());
- printk(KERN_INFO "%ld free buffer pages\n", nr_free_buffer_pages());
-}
-
-
/* physical address where the bootmem map is located */
unsigned long bootmap_start;

diff --git a/arch/ia64/mm/discontig.c b/arch/ia64/mm/discontig.c
index 2de08f4..8786268 100644
--- a/arch/ia64/mm/discontig.c
+++ b/arch/ia64/mm/discontig.c
@@ -608,69 +608,6 @@ void *per_cpu_init(void)
#endif /* CONFIG_SMP */

/**
- * show_mem - give short summary of memory stats
- *
- * Shows a simple page count of reserved and used pages in the system.
- * For discontig machines, it does this on a per-pgdat basis.
- */
-void show_mem(unsigned int filter)
-{
- int i, total_reserved = 0;
- int total_shared = 0, total_cached = 0;
- unsigned long total_present = 0;
- pg_data_t *pgdat;
-
- printk(KERN_INFO "Mem-info:\n");
- show_free_areas(filter);
- if (filter & SHOW_MEM_FILTER_PAGE_COUNT)
- return;
- printk(KERN_INFO "Node memory in pages:\n");
- for_each_online_pgdat(pgdat) {
- unsigned long present;
- unsigned long flags;
- int shared = 0, cached = 0, reserved = 0;
- int nid = pgdat->node_id;
-
- if (skip_free_areas_node(filter, nid))
- continue;
- pgdat_resize_lock(pgdat, &flags);
- present = pgdat->node_present_pages;
- for(i = 0; i < pgdat->node_spanned_pages; i++) {
- struct page *page;
- if (unlikely(i % MAX_ORDER_NR_PAGES == 0))
- touch_nmi_watchdog();
- if (pfn_valid(pgdat->node_start_pfn + i))
- page = pfn_to_page(pgdat->node_start_pfn + i);
- else {
- i = vmemmap_find_next_valid_pfn(nid, i) - 1;
- continue;
- }
- if (PageReserved(page))
- reserved++;
- else if (PageSwapCache(page))
- cached++;
- else if (page_count(page))
- shared += page_count(page)-1;
- }
- pgdat_resize_unlock(pgdat, &flags);
- total_present += present;
- total_reserved += reserved;
- total_cached += cached;
- total_shared += shared;
- printk(KERN_INFO "Node %4d: RAM: %11ld, rsvd: %8d, "
- "shrd: %10d, swpd: %10d\n", nid,
- present, reserved, shared, cached);
- }
- printk(KERN_INFO "%ld pages of RAM\n", total_present);
- printk(KERN_INFO "%d reserved pages\n", total_reserved);
- printk(KERN_INFO "%d pages shared\n", total_shared);
- printk(KERN_INFO "%d pages swap cached\n", total_cached);
- printk(KERN_INFO "Total of %ld pages in page table cache\n",
- quicklist_total_size());
- printk(KERN_INFO "%ld free buffer pages\n", nr_free_buffer_pages());
-}
-
-/**
* call_pernode_memory - use SRAT to call callback functions with node info
* @start: physical start of range
* @len: length of range
diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 88504ab..25c3502 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -684,3 +684,51 @@ per_linux32_init(void)
}

__initcall(per_linux32_init);
+
+/**
+ * show_mem - give short summary of memory stats
+ *
+ * Shows a simple page count of reserved and used pages in the system.
+ * For discontig machines, it does this on a per-pgdat basis.
+ */
+void show_mem(unsigned int filter)
+{
+ int total_reserved = 0;
+ unsigned long total_present = 0;
+ pg_data_t *pgdat;
+
+ printk(KERN_INFO "Mem-info:\n");
+ show_free_areas(filter);
+ printk(KERN_INFO "Node memory in pages:\n");
+ for_each_online_pgdat(pgdat) {
+ unsigned long present;
+ unsigned long flags;
+ int reserved = 0;
+ int nid = pgdat->node_id;
+ int zoneid;
+
+ if (skip_free_areas_node(filter, nid))
+ continue;
+ pgdat_resize_lock(pgdat, &flags);
+
+ for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) {
+ struct zone *zone = &pgdat->node_zones[zoneid];
+ if (!populated_zone(zone))
+ continue;
+
+ reserved += zone->present_pages - zone->managed_pages;
+ }
+ present = pgdat->node_present_pages;
+
+ pgdat_resize_unlock(pgdat, &flags);
+ total_present += present;
+ total_reserved += reserved;
+ printk(KERN_INFO "Node %4d: RAM: %11ld, rsvd: %8d, ",
+ nid, present, reserved);
+ }
+ printk(KERN_INFO "%ld pages of RAM\n", total_present);
+ printk(KERN_INFO "%d reserved pages\n", total_reserved);
+ printk(KERN_INFO "Total of %ld pages in page table cache\n",
+ quicklist_total_size());
+ printk(KERN_INFO "%ld free buffer pages\n", nr_free_buffer_pages());
+}
diff --git a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c
index b0f96c0..e12d5a7 100644
--- a/arch/parisc/mm/init.c
+++ b/arch/parisc/mm/init.c
@@ -632,55 +632,33 @@ EXPORT_SYMBOL(empty_zero_page);

void show_mem(unsigned int filter)
{
- int i,free = 0,total = 0,reserved = 0;
- int shared = 0, cached = 0;
+ int total = 0,reserved = 0;
+ pg_data_t *pgdat;

printk(KERN_INFO "Mem-info:\n");
show_free_areas(filter);
- if (filter & SHOW_MEM_FILTER_PAGE_COUNT)
- return;
-#ifndef CONFIG_DISCONTIGMEM
- i = max_mapnr;
- while (i-- > 0) {
- total++;
- if (PageReserved(mem_map+i))
- reserved++;
- else if (PageSwapCache(mem_map+i))
- cached++;
- else if (!page_count(&mem_map[i]))
- free++;
- else
- shared += page_count(&mem_map[i]) - 1;
- }
-#else
- for (i = 0; i < npmem_ranges; i++) {
- int j;

- for (j = node_start_pfn(i); j < node_end_pfn(i); j++) {
- struct page *p;
- unsigned long flags;
-
- pgdat_resize_lock(NODE_DATA(i), &flags);
- p = nid_page_nr(i, j) - node_start_pfn(i);
-
- total++;
- if (PageReserved(p))
- reserved++;
- else if (PageSwapCache(p))
- cached++;
- else if (!page_count(p))
- free++;
- else
- shared += page_count(p) - 1;
- pgdat_resize_unlock(NODE_DATA(i), &flags);
- }
+ for_each_online_pgdat(pgdat) {
+ unsigned long flags;
+ int zoneid;
+
+ pgdat_resize_lock(pgdat, &flags);
+ for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) {
+ struct zone *zone = &pgdat->node_zones[zoneid];
+ if (!populated_zone(zone))
+ continue;
+
+ total += zone->present_pages;
+ reserved = zone->present_pages - zone->managed_pages;
+
+ if (is_highmem_idx(zoneid))
+ highmem += zone->present_pages;
+ }
+ pgdat_resize_unlock(pgdat, &flags);
}
-#endif
+
printk(KERN_INFO "%d pages of RAM\n", total);
printk(KERN_INFO "%d reserved pages\n", reserved);
- printk(KERN_INFO "%d pages shared\n", shared);
- printk(KERN_INFO "%d pages swap cached\n", cached);
-

#ifdef CONFIG_DISCONTIGMEM
{
diff --git a/arch/unicore32/mm/init.c b/arch/unicore32/mm/init.c
index ae6bc03..be2bde9 100644
--- a/arch/unicore32/mm/init.c
+++ b/arch/unicore32/mm/init.c
@@ -66,9 +66,6 @@ void show_mem(unsigned int filter)
printk(KERN_DEFAULT "Mem-info:\n");
show_free_areas(filter);

- if (filter & SHOW_MEM_FILTER_PAGE_COUNT)
- return;
-
for_each_bank(i, mi) {
struct membank *bank = &mi->bank[i];
unsigned int pfn1, pfn2;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1cedd00..42b2486 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -984,7 +984,6 @@ extern void pagefault_out_of_memory(void);
* various contexts.
*/
#define SHOW_MEM_FILTER_NODES (0x0001u) /* disallowed nodes */
-#define SHOW_MEM_FILTER_PAGE_COUNT (0x0002u) /* page type count */

extern void show_free_areas(unsigned int flags);
extern bool skip_free_areas_node(unsigned int flags, int nid);
diff --git a/lib/show_mem.c b/lib/show_mem.c
index 5847a49..f58689f 100644
--- a/lib/show_mem.c
+++ b/lib/show_mem.c
@@ -17,9 +17,6 @@ void show_mem(unsigned int filter)
printk("Mem-Info:\n");
show_free_areas(filter);

- if (filter & SHOW_MEM_FILTER_PAGE_COUNT)
- return;
-
for_each_online_pgdat(pgdat) {
unsigned long flags;
int zoneid;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 580a5f0..dcb61e8 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2073,13 +2073,6 @@ void warn_alloc_failed(gfp_t gfp_mask, int order, const char *fmt, ...)
return;

/*
- * Walking all memory to count page types is very expensive and should
- * be inhibited in non-blockable contexts.
- */
- if (!(gfp_mask & __GFP_WAIT))
- filter |= SHOW_MEM_FILTER_PAGE_COUNT;
-
- /*
* This documents exceptions given to allocations in certain
* contexts that are allowed to allocate outside current's set
* of allowed nodes.
--
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