forked from luck/tmp_suning_uos_patched
031bc5743f
Now, we have prepared to avoid using debug-pagealloc in boottime. So introduce new kernel-parameter to disable debug-pagealloc in boottime, and makes related functions to be disabled in this case. Only non-intuitive part is change of guard page functions. Because guard page is effective only if debug-pagealloc is enabled, turning off according to debug-pagealloc is reasonable thing to do. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Dave Hansen <dave@sr71.net> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Jungsoo Son <jungsoo.son@lge.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
138 lines
2.6 KiB
C
138 lines
2.6 KiB
C
#include <linux/kernel.h>
|
|
#include <linux/string.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/highmem.h>
|
|
#include <linux/page_ext.h>
|
|
#include <linux/poison.h>
|
|
#include <linux/ratelimit.h>
|
|
|
|
static bool page_poisoning_enabled __read_mostly;
|
|
|
|
static bool need_page_poisoning(void)
|
|
{
|
|
if (!debug_pagealloc_enabled())
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
static void init_page_poisoning(void)
|
|
{
|
|
if (!debug_pagealloc_enabled())
|
|
return;
|
|
|
|
page_poisoning_enabled = true;
|
|
}
|
|
|
|
struct page_ext_operations page_poisoning_ops = {
|
|
.need = need_page_poisoning,
|
|
.init = init_page_poisoning,
|
|
};
|
|
|
|
static inline void set_page_poison(struct page *page)
|
|
{
|
|
struct page_ext *page_ext;
|
|
|
|
page_ext = lookup_page_ext(page);
|
|
__set_bit(PAGE_EXT_DEBUG_POISON, &page_ext->flags);
|
|
}
|
|
|
|
static inline void clear_page_poison(struct page *page)
|
|
{
|
|
struct page_ext *page_ext;
|
|
|
|
page_ext = lookup_page_ext(page);
|
|
__clear_bit(PAGE_EXT_DEBUG_POISON, &page_ext->flags);
|
|
}
|
|
|
|
static inline bool page_poison(struct page *page)
|
|
{
|
|
struct page_ext *page_ext;
|
|
|
|
page_ext = lookup_page_ext(page);
|
|
return test_bit(PAGE_EXT_DEBUG_POISON, &page_ext->flags);
|
|
}
|
|
|
|
static void poison_page(struct page *page)
|
|
{
|
|
void *addr = kmap_atomic(page);
|
|
|
|
set_page_poison(page);
|
|
memset(addr, PAGE_POISON, PAGE_SIZE);
|
|
kunmap_atomic(addr);
|
|
}
|
|
|
|
static void poison_pages(struct page *page, int n)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < n; i++)
|
|
poison_page(page + i);
|
|
}
|
|
|
|
static bool single_bit_flip(unsigned char a, unsigned char b)
|
|
{
|
|
unsigned char error = a ^ b;
|
|
|
|
return error && !(error & (error - 1));
|
|
}
|
|
|
|
static void check_poison_mem(unsigned char *mem, size_t bytes)
|
|
{
|
|
static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 10);
|
|
unsigned char *start;
|
|
unsigned char *end;
|
|
|
|
start = memchr_inv(mem, PAGE_POISON, bytes);
|
|
if (!start)
|
|
return;
|
|
|
|
for (end = mem + bytes - 1; end > start; end--) {
|
|
if (*end != PAGE_POISON)
|
|
break;
|
|
}
|
|
|
|
if (!__ratelimit(&ratelimit))
|
|
return;
|
|
else if (start == end && single_bit_flip(*start, PAGE_POISON))
|
|
printk(KERN_ERR "pagealloc: single bit error\n");
|
|
else
|
|
printk(KERN_ERR "pagealloc: memory corruption\n");
|
|
|
|
print_hex_dump(KERN_ERR, "", DUMP_PREFIX_ADDRESS, 16, 1, start,
|
|
end - start + 1, 1);
|
|
dump_stack();
|
|
}
|
|
|
|
static void unpoison_page(struct page *page)
|
|
{
|
|
void *addr;
|
|
|
|
if (!page_poison(page))
|
|
return;
|
|
|
|
addr = kmap_atomic(page);
|
|
check_poison_mem(addr, PAGE_SIZE);
|
|
clear_page_poison(page);
|
|
kunmap_atomic(addr);
|
|
}
|
|
|
|
static void unpoison_pages(struct page *page, int n)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < n; i++)
|
|
unpoison_page(page + i);
|
|
}
|
|
|
|
void __kernel_map_pages(struct page *page, int numpages, int enable)
|
|
{
|
|
if (!page_poisoning_enabled)
|
|
return;
|
|
|
|
if (enable)
|
|
unpoison_pages(page, numpages);
|
|
else
|
|
poison_pages(page, numpages);
|
|
}
|