mm/show_mem.c

Source file repositories/reference/linux-study-clean/mm/show_mem.c

File Facts

System
Linux kernel
Corpus path
mm/show_mem.c
Extension
.c
Size
13204 bytes
Lines
465
Domain
Core OS
Bucket
Memory Management
Inferred role
Core OS: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

if (is_highmem(zone)) {
			managed_highpages += zone_managed_pages(zone);
			free_highpages += zone_page_state(zone, NR_FREE_PAGES);
		}
	}

	val->totalram = managed_pages;
	val->sharedram = node_page_state(pgdat, NR_SHMEM);
	val->freeram = sum_zone_node_page_state(nid, NR_FREE_PAGES);
	val->totalhigh = managed_highpages;
	val->freehigh = free_highpages;
	val->mem_unit = PAGE_SIZE;
}
#endif

/*
 * Determine whether the node should be displayed or not, depending on whether
 * SHOW_MEM_FILTER_NODES was passed to show_free_areas().
 */
static bool show_mem_node_skip(unsigned int flags, int nid, nodemask_t *nodemask)
{
	if (!(flags & SHOW_MEM_FILTER_NODES))
		return false;

	/*
	 * no node mask - aka implicit memory numa policy. Do not bother with
	 * the synchronization - read_mems_allowed_begin - because we do not
	 * have to be precise here.
	 */
	if (!nodemask)
		nodemask = &cpuset_current_mems_allowed;

	return !node_isset(nid, *nodemask);
}

static void show_migration_types(unsigned char type)
{
	static const char types[MIGRATE_TYPES] = {
		[MIGRATE_UNMOVABLE]	= 'U',
		[MIGRATE_MOVABLE]	= 'M',
		[MIGRATE_RECLAIMABLE]	= 'E',
		[MIGRATE_HIGHATOMIC]	= 'H',
#ifdef CONFIG_CMA
		[MIGRATE_CMA]		= 'C',
#endif
#ifdef CONFIG_MEMORY_ISOLATION
		[MIGRATE_ISOLATE]	= 'I',
#endif
	};
	char tmp[MIGRATE_TYPES + 1];
	char *p = tmp;
	int i;

	for (i = 0; i < MIGRATE_TYPES; i++) {
		if (type & (1 << i))
			*p++ = types[i];
	}

	*p = '\0';
	printk(KERN_CONT "(%s) ", tmp);
}

static bool node_has_managed_zones(pg_data_t *pgdat, int max_zone_idx)
{
	int zone_idx;
	for (zone_idx = 0; zone_idx <= max_zone_idx; zone_idx++)
		if (zone_managed_pages(pgdat->node_zones + zone_idx))
			return true;
	return false;
}

/*
 * Show free area list (used inside shift_scroll-lock stuff)
 * We also calculate the percentage fragmentation. We do this by counting the
 * memory on each free list with the exception of the first item on the list.
 *
 * Bits in @filter:
 * SHOW_MEM_FILTER_NODES: suppress nodes that are not allowed by current's
 *   cpuset.
 */
static void show_free_areas(unsigned int filter, nodemask_t *nodemask, int max_zone_idx)
{
	unsigned long free_pcp = 0;
	int cpu, nid;
	struct zone *zone;
	pg_data_t *pgdat;

	for_each_populated_zone(zone) {
		if (zone_idx(zone) > max_zone_idx)
			continue;

Annotation

Implementation Notes