mm/memtest.c

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

File Facts

System
Linux kernel
Corpus path
mm/memtest.c
Extension
.c
Size
3592 bytes
Lines
140
Domain
Core OS
Bucket
Memory Management
Inferred role
Core OS: implementation source
Status
source 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 (start_phys_aligned == last_bad + incr) {
			last_bad += incr;
			continue;
		}
		if (start_bad)
			reserve_bad_mem(pattern, start_bad, last_bad + incr);
		start_bad = last_bad = start_phys_aligned;
	}
	if (start_bad)
		reserve_bad_mem(pattern, start_bad, last_bad + incr);

	early_memtest_done = true;
}

static void __init do_one_pass(u64 pattern, phys_addr_t start, phys_addr_t end)
{
	u64 i;
	phys_addr_t this_start, this_end;

	for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE, &this_start,
				&this_end, NULL) {
		this_start = clamp(this_start, start, end);
		this_end = clamp(this_end, start, end);
		if (this_start < this_end) {
			pr_info("  %pa - %pa pattern %016llx\n",
				&this_start, &this_end, cpu_to_be64(pattern));
			memtest(pattern, this_start, this_end - this_start);
		}
	}
}

/* default is disabled */
static unsigned int memtest_pattern __initdata;

static int __init parse_memtest(char *arg)
{
	int ret = 0;

	if (arg)
		ret = kstrtouint(arg, 0, &memtest_pattern);
	else
		memtest_pattern = ARRAY_SIZE(patterns);

	return ret;
}

early_param("memtest", parse_memtest);

void __init early_memtest(phys_addr_t start, phys_addr_t end)
{
	unsigned int i;
	unsigned int idx = 0;

	if (!memtest_pattern)
		return;

	pr_info("early_memtest: # of tests: %u\n", memtest_pattern);
	for (i = memtest_pattern-1; i < UINT_MAX; --i) {
		idx = i % ARRAY_SIZE(patterns);
		do_one_pass(patterns[idx], start, end);
	}
}

void memtest_report_meminfo(struct seq_file *m)
{
	unsigned long early_memtest_bad_size_kb;

	if (!IS_ENABLED(CONFIG_PROC_FS))
		return;

	if (!early_memtest_done)
		return;

	early_memtest_bad_size_kb = early_memtest_bad_size >> 10;
	if (early_memtest_bad_size && !early_memtest_bad_size_kb)
		early_memtest_bad_size_kb = 1;
	/* When 0 is reported, it means there actually was a successful test */
	seq_printf(m, "EarlyMemtestBad:   %5lu kB\n", early_memtest_bad_size_kb);
}

Annotation

Implementation Notes