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-rw-r--r--mm/bootmem.c35
-rw-r--r--mm/filemap.c11
-rw-r--r--mm/filemap_xip.c65
-rw-r--r--mm/memcontrol.c18
-rw-r--r--mm/mm_init.c2
-rw-r--r--mm/mmap.c4
-rw-r--r--mm/mmzone.c2
-rw-r--r--mm/page_alloc.c9
-rw-r--r--mm/page_isolation.c1
-rw-r--r--mm/quicklist.c9
-rw-r--r--mm/rmap.c39
-rw-r--r--mm/slub.c5
-rw-r--r--mm/swap_state.c2
-rw-r--r--mm/tiny-shmem.c24
-rw-r--r--mm/truncate.c4
-rw-r--r--mm/vmstat.c19
16 files changed, 186 insertions, 63 deletions
diff --git a/mm/bootmem.c b/mm/bootmem.c
index e023c68b025..ad8eec6e44a 100644
--- a/mm/bootmem.c
+++ b/mm/bootmem.c
@@ -405,6 +405,29 @@ int __init reserve_bootmem(unsigned long addr, unsigned long size,
}
#endif /* !CONFIG_HAVE_ARCH_BOOTMEM_NODE */
+static unsigned long align_idx(struct bootmem_data *bdata, unsigned long idx,
+ unsigned long step)
+{
+ unsigned long base = bdata->node_min_pfn;
+
+ /*
+ * Align the index with respect to the node start so that the
+ * combination of both satisfies the requested alignment.
+ */
+
+ return ALIGN(base + idx, step) - base;
+}
+
+static unsigned long align_off(struct bootmem_data *bdata, unsigned long off,
+ unsigned long align)
+{
+ unsigned long base = PFN_PHYS(bdata->node_min_pfn);
+
+ /* Same as align_idx for byte offsets */
+
+ return ALIGN(base + off, align) - base;
+}
+
static void * __init alloc_bootmem_core(struct bootmem_data *bdata,
unsigned long size, unsigned long align,
unsigned long goal, unsigned long limit)
@@ -441,7 +464,7 @@ static void * __init alloc_bootmem_core(struct bootmem_data *bdata,
else
start = ALIGN(min, step);
- sidx = start - bdata->node_min_pfn;;
+ sidx = start - bdata->node_min_pfn;
midx = max - bdata->node_min_pfn;
if (bdata->hint_idx > sidx) {
@@ -450,7 +473,7 @@ static void * __init alloc_bootmem_core(struct bootmem_data *bdata,
* catch the fallback below.
*/
fallback = sidx + 1;
- sidx = ALIGN(bdata->hint_idx, step);
+ sidx = align_idx(bdata, bdata->hint_idx, step);
}
while (1) {
@@ -459,7 +482,7 @@ static void * __init alloc_bootmem_core(struct bootmem_data *bdata,
unsigned long eidx, i, start_off, end_off;
find_block:
sidx = find_next_zero_bit(bdata->node_bootmem_map, midx, sidx);
- sidx = ALIGN(sidx, step);
+ sidx = align_idx(bdata, sidx, step);
eidx = sidx + PFN_UP(size);
if (sidx >= midx || eidx > midx)
@@ -467,7 +490,7 @@ find_block:
for (i = sidx; i < eidx; i++)
if (test_bit(i, bdata->node_bootmem_map)) {
- sidx = ALIGN(i, step);
+ sidx = align_idx(bdata, i, step);
if (sidx == i)
sidx += step;
goto find_block;
@@ -475,7 +498,7 @@ find_block:
if (bdata->last_end_off & (PAGE_SIZE - 1) &&
PFN_DOWN(bdata->last_end_off) + 1 == sidx)
- start_off = ALIGN(bdata->last_end_off, align);
+ start_off = align_off(bdata, bdata->last_end_off, align);
else
start_off = PFN_PHYS(sidx);
@@ -499,7 +522,7 @@ find_block:
}
if (fallback) {
- sidx = ALIGN(fallback - 1, step);
+ sidx = align_idx(bdata, fallback - 1, step);
fallback = 0;
goto find_block;
}
diff --git a/mm/filemap.c b/mm/filemap.c
index 54e96865085..876bc595d0f 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2129,13 +2129,20 @@ generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
* After a write we want buffered reads to be sure to go to disk to get
* the new data. We invalidate clean cached page from the region we're
* about to write. We do this *before* the write so that we can return
- * -EIO without clobbering -EIOCBQUEUED from ->direct_IO().
+ * without clobbering -EIOCBQUEUED from ->direct_IO().
*/
if (mapping->nrpages) {
written = invalidate_inode_pages2_range(mapping,
pos >> PAGE_CACHE_SHIFT, end);
- if (written)
+ /*
+ * If a page can not be invalidated, return 0 to fall back
+ * to buffered write.
+ */
+ if (written) {
+ if (written == -EBUSY)
+ return 0;
goto out;
+ }
}
written = mapping->a_ops->direct_IO(WRITE, iocb, iov, pos, *nr_segs);
diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
index 380ab402d71..b5167dfb2f2 100644
--- a/mm/filemap_xip.c
+++ b/mm/filemap_xip.c
@@ -15,6 +15,8 @@
#include <linux/rmap.h>
#include <linux/mmu_notifier.h>
#include <linux/sched.h>
+#include <linux/seqlock.h>
+#include <linux/mutex.h>
#include <asm/tlbflush.h>
#include <asm/io.h>
@@ -22,22 +24,18 @@
* We do use our own empty page to avoid interference with other users
* of ZERO_PAGE(), such as /dev/zero
*/
+static DEFINE_MUTEX(xip_sparse_mutex);
+static seqcount_t xip_sparse_seq = SEQCNT_ZERO;
static struct page *__xip_sparse_page;
+/* called under xip_sparse_mutex */
static struct page *xip_sparse_page(void)
{
if (!__xip_sparse_page) {
struct page *page = alloc_page(GFP_HIGHUSER | __GFP_ZERO);
- if (page) {
- static DEFINE_SPINLOCK(xip_alloc_lock);
- spin_lock(&xip_alloc_lock);
- if (!__xip_sparse_page)
- __xip_sparse_page = page;
- else
- __free_page(page);
- spin_unlock(&xip_alloc_lock);
- }
+ if (page)
+ __xip_sparse_page = page;
}
return __xip_sparse_page;
}
@@ -174,18 +172,23 @@ __xip_unmap (struct address_space * mapping,
pte_t pteval;
spinlock_t *ptl;
struct page *page;
+ unsigned count;
+ int locked = 0;
+
+ count = read_seqcount_begin(&xip_sparse_seq);
page = __xip_sparse_page;
if (!page)
return;
+retry:
spin_lock(&mapping->i_mmap_lock);
vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
mm = vma->vm_mm;
address = vma->vm_start +
((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
BUG_ON(address < vma->vm_start || address >= vma->vm_end);
- pte = page_check_address(page, mm, address, &ptl);
+ pte = page_check_address(page, mm, address, &ptl, 1);
if (pte) {
/* Nuke the page table entry. */
flush_cache_page(vma, address, pte_pfn(*pte));
@@ -198,6 +201,14 @@ __xip_unmap (struct address_space * mapping,
}
}
spin_unlock(&mapping->i_mmap_lock);
+
+ if (locked) {
+ mutex_unlock(&xip_sparse_mutex);
+ } else if (read_seqcount_retry(&xip_sparse_seq, count)) {
+ mutex_lock(&xip_sparse_mutex);
+ locked = 1;
+ goto retry;
+ }
}
/*
@@ -218,7 +229,7 @@ static int xip_file_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
int error;
/* XXX: are VM_FAULT_ codes OK? */
-
+again:
size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
if (vmf->pgoff >= size)
return VM_FAULT_SIGBUS;
@@ -237,8 +248,10 @@ static int xip_file_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
int err;
/* maybe shared writable, allocate new block */
+ mutex_lock(&xip_sparse_mutex);
error = mapping->a_ops->get_xip_mem(mapping, vmf->pgoff, 1,
&xip_mem, &xip_pfn);
+ mutex_unlock(&xip_sparse_mutex);
if (error)
return VM_FAULT_SIGBUS;
/* unmap sparse mappings at pgoff from all other vmas */
@@ -252,14 +265,34 @@ found:
BUG_ON(err);
return VM_FAULT_NOPAGE;
} else {
+ int err, ret = VM_FAULT_OOM;
+
+ mutex_lock(&xip_sparse_mutex);
+ write_seqcount_begin(&xip_sparse_seq);
+ error = mapping->a_ops->get_xip_mem(mapping, vmf->pgoff, 0,
+ &xip_mem, &xip_pfn);
+ if (unlikely(!error)) {
+ write_seqcount_end(&xip_sparse_seq);
+ mutex_unlock(&xip_sparse_mutex);
+ goto again;
+ }
+ if (error != -ENODATA)
+ goto out;
/* not shared and writable, use xip_sparse_page() */
page = xip_sparse_page();
if (!page)
- return VM_FAULT_OOM;
+ goto out;
+ err = vm_insert_page(vma, (unsigned long)vmf->virtual_address,
+ page);
+ if (err == -ENOMEM)
+ goto out;
- page_cache_get(page);
- vmf->page = page;
- return 0;
+ ret = VM_FAULT_NOPAGE;
+out:
+ write_seqcount_end(&xip_sparse_seq);
+ mutex_unlock(&xip_sparse_mutex);
+
+ return ret;
}
}
@@ -308,8 +341,10 @@ __xip_file_write(struct file *filp, const char __user *buf,
&xip_mem, &xip_pfn);
if (status == -ENODATA) {
/* we allocate a new page unmap it */
+ mutex_lock(&xip_sparse_mutex);
status = a_ops->get_xip_mem(mapping, index, 1,
&xip_mem, &xip_pfn);
+ mutex_unlock(&xip_sparse_mutex);
if (!status)
/* unmap page at pgoff from all other vmas */
__xip_unmap(mapping, index);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 0f1f7a7374b..36896f3eb7f 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -250,6 +250,14 @@ static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
{
+ /*
+ * mm_update_next_owner() may clear mm->owner to NULL
+ * if it races with swapoff, page migration, etc.
+ * So this can be called with p == NULL.
+ */
+ if (unlikely(!p))
+ return NULL;
+
return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
struct mem_cgroup, css);
}
@@ -549,6 +557,11 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
if (likely(!memcg)) {
rcu_read_lock();
mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
+ if (unlikely(!mem)) {
+ rcu_read_unlock();
+ kmem_cache_free(page_cgroup_cache, pc);
+ return 0;
+ }
/*
* For every charge from the cgroup, increment reference count
*/
@@ -801,11 +814,16 @@ int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask)
rcu_read_lock();
mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
+ if (unlikely(!mem)) {
+ rcu_read_unlock();
+ return 0;
+ }
css_get(&mem->css);
rcu_read_unlock();
do {
progress = try_to_free_mem_cgroup_pages(mem, gfp_mask);
+ progress += res_counter_check_under_limit(&mem->res);
} while (!progress && --retry);
css_put(&mem->css);
diff --git a/mm/mm_init.c b/mm/mm_init.c
index 936ef2efd89..4e0e26591df 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -12,7 +12,7 @@
#include "internal.h"
#ifdef CONFIG_DEBUG_MEMORY_INIT
-int __meminitdata mminit_loglevel;
+int mminit_loglevel;
#ifndef SECTIONS_SHIFT
#define SECTIONS_SHIFT 0
diff --git a/mm/mmap.c b/mm/mmap.c
index 339cf5c4d5d..e7a5a68a9c2 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1030,6 +1030,10 @@ unsigned long do_mmap_pgoff(struct file * file, unsigned long addr,
} else {
switch (flags & MAP_TYPE) {
case MAP_SHARED:
+ /*
+ * Ignore pgoff.
+ */
+ pgoff = 0;
vm_flags |= VM_SHARED | VM_MAYSHARE;
break;
case MAP_PRIVATE:
diff --git a/mm/mmzone.c b/mm/mmzone.c
index 486ed595ee6..16ce8b955dc 100644
--- a/mm/mmzone.c
+++ b/mm/mmzone.c
@@ -69,6 +69,6 @@ struct zoneref *next_zones_zonelist(struct zoneref *z,
(z->zone && !zref_in_nodemask(z, nodes)))
z++;
- *zone = zonelist_zone(z++);
+ *zone = zonelist_zone(z);
return z;
}
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index af982f7cdb2..e293c58bea5 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -694,6 +694,9 @@ static int move_freepages(struct zone *zone,
#endif
for (page = start_page; page <= end_page;) {
+ /* Make sure we are not inadvertently changing nodes */
+ VM_BUG_ON(page_to_nid(page) != zone_to_nid(zone));
+
if (!pfn_valid_within(page_to_pfn(page))) {
page++;
continue;
@@ -2516,6 +2519,10 @@ static void setup_zone_migrate_reserve(struct zone *zone)
continue;
page = pfn_to_page(pfn);
+ /* Watch out for overlapping nodes */
+ if (page_to_nid(page) != zone_to_nid(zone))
+ continue;
+
/* Blocks with reserved pages will never free, skip them. */
if (PageReserved(page))
continue;
@@ -4064,7 +4071,7 @@ void __init set_dma_reserve(unsigned long new_dma_reserve)
}
#ifndef CONFIG_NEED_MULTIPLE_NODES
-struct pglist_data contig_page_data = { .bdata = &bootmem_node_data[0] };
+struct pglist_data __refdata contig_page_data = { .bdata = &bootmem_node_data[0] };
EXPORT_SYMBOL(contig_page_data);
#endif
diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 3444b58033c..c69f84fe038 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -2,7 +2,6 @@
* linux/mm/page_isolation.c
*/
-#include <stddef.h>
#include <linux/mm.h>
#include <linux/page-isolation.h>
#include <linux/pageblock-flags.h>
diff --git a/mm/quicklist.c b/mm/quicklist.c
index 3f703f7cb39..8dbb6805ef3 100644
--- a/mm/quicklist.c
+++ b/mm/quicklist.c
@@ -26,7 +26,10 @@ DEFINE_PER_CPU(struct quicklist, quicklist)[CONFIG_NR_QUICK];
static unsigned long max_pages(unsigned long min_pages)
{
unsigned long node_free_pages, max;
- struct zone *zones = NODE_DATA(numa_node_id())->node_zones;
+ int node = numa_node_id();
+ struct zone *zones = NODE_DATA(node)->node_zones;
+ int num_cpus_on_node;
+ node_to_cpumask_ptr(cpumask_on_node, node);
node_free_pages =
#ifdef CONFIG_ZONE_DMA
@@ -38,6 +41,10 @@ static unsigned long max_pages(unsigned long min_pages)
zone_page_state(&zones[ZONE_NORMAL], NR_FREE_PAGES);
max = node_free_pages / FRACTION_OF_NODE_MEM;
+
+ num_cpus_on_node = cpus_weight_nr(*cpumask_on_node);
+ max /= num_cpus_on_node;
+
return max(max, min_pages);
}
diff --git a/mm/rmap.c b/mm/rmap.c
index 1ea4e6fcee7..0383acfcb06 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -224,10 +224,14 @@ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
/*
* Check that @page is mapped at @address into @mm.
*
+ * If @sync is false, page_check_address may perform a racy check to avoid
+ * the page table lock when the pte is not present (helpful when reclaiming
+ * highly shared pages).
+ *
* On success returns with pte mapped and locked.
*/
pte_t *page_check_address(struct page *page, struct mm_struct *mm,
- unsigned long address, spinlock_t **ptlp)
+ unsigned long address, spinlock_t **ptlp, int sync)
{
pgd_t *pgd;
pud_t *pud;
@@ -249,7 +253,7 @@ pte_t *page_check_address(struct page *page, struct mm_struct *mm,
pte = pte_offset_map(pmd, address);
/* Make a quick check before getting the lock */
- if (!pte_present(*pte)) {
+ if (!sync && !pte_present(*pte)) {
pte_unmap(pte);
return NULL;
}
@@ -281,7 +285,7 @@ static int page_referenced_one(struct page *page,
if (address == -EFAULT)
goto out;
- pte = page_check_address(page, mm, address, &ptl);
+ pte = page_check_address(page, mm, address, &ptl, 0);
if (!pte)
goto out;
@@ -450,7 +454,7 @@ static int page_mkclean_one(struct page *page, struct vm_area_struct *vma)
if (address == -EFAULT)
goto out;
- pte = page_check_address(page, mm, address, &ptl);
+ pte = page_check_address(page, mm, address, &ptl, 1);
if (!pte)
goto out;
@@ -659,23 +663,30 @@ void page_remove_rmap(struct page *page, struct vm_area_struct *vma)
}
/*
- * It would be tidy to reset the PageAnon mapping here,
- * but that might overwrite a racing page_add_anon_rmap
- * which increments mapcount after us but sets mapping
- * before us: so leave the reset to free_hot_cold_page,
- * and remember that it's only reliable while mapped.
- * Leaving it set also helps swapoff to reinstate ptes
- * faster for those pages still in swapcache.
+ * Now that the last pte has gone, s390 must transfer dirty
+ * flag from storage key to struct page. We can usually skip
+ * this if the page is anon, so about to be freed; but perhaps
+ * not if it's in swapcache - there might be another pte slot
+ * containing the swap entry, but page not yet written to swap.
*/
if ((!PageAnon(page) || PageSwapCache(page)) &&
page_test_dirty(page)) {
page_clear_dirty(page);
set_page_dirty(page);
}
- mem_cgroup_uncharge_page(page);
+ mem_cgroup_uncharge_page(page);
__dec_zone_page_state(page,
- PageAnon(page) ? NR_ANON_PAGES : NR_FILE_MAPPED);
+ PageAnon(page) ? NR_ANON_PAGES : NR_FILE_MAPPED);
+ /*
+ * It would be tidy to reset the PageAnon mapping here,
+ * but that might overwrite a racing page_add_anon_rmap
+ * which increments mapcount after us but sets mapping
+ * before us: so leave the reset to free_hot_cold_page,
+ * and remember that it's only reliable while mapped.
+ * Leaving it set also helps swapoff to reinstate ptes
+ * faster for those pages still in swapcache.
+ */
}
}
@@ -697,7 +708,7 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
if (address == -EFAULT)
goto out;
- pte = page_check_address(page, mm, address, &ptl);
+ pte = page_check_address(page, mm, address, &ptl, 0);
if (!pte)
goto out;
diff --git a/mm/slub.c b/mm/slub.c
index 4f5b9614945..0c83e6afe7b 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1932,6 +1932,7 @@ init_kmem_cache_node(struct kmem_cache_node *n, struct kmem_cache *s)
INIT_LIST_HEAD(&n->partial);
#ifdef CONFIG_SLUB_DEBUG
atomic_long_set(&n->nr_slabs, 0);
+ atomic_long_set(&n->total_objects, 0);
INIT_LIST_HEAD(&n->full);
#endif
}
@@ -2312,7 +2313,7 @@ static int kmem_cache_open(struct kmem_cache *s, gfp_t gfpflags,
s->refcount = 1;
#ifdef CONFIG_NUMA
- s->remote_node_defrag_ratio = 100;
+ s->remote_node_defrag_ratio = 1000;
#endif
if (!init_kmem_cache_nodes(s, gfpflags & ~SLUB_DMA))
goto error;
@@ -4058,7 +4059,7 @@ static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
if (err)
return err;
- if (ratio < 100)
+ if (ratio <= 100)
s->remote_node_defrag_ratio = ratio * 10;
return length;
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 167cf2dc8a0..797c3831cbe 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -60,7 +60,7 @@ void show_swap_cache_info(void)
printk("Swap cache stats: add %lu, delete %lu, find %lu/%lu\n",
swap_cache_info.add_total, swap_cache_info.del_total,
swap_cache_info.find_success, swap_cache_info.find_total);
- printk("Free swap = %lukB\n", nr_swap_pages << (PAGE_SHIFT - 10));
+ printk("Free swap = %ldkB\n", nr_swap_pages << (PAGE_SHIFT - 10));
printk("Total swap = %lukB\n", total_swap_pages << (PAGE_SHIFT - 10));
}
diff --git a/mm/tiny-shmem.c b/mm/tiny-shmem.c
index ae532f50194..d17cb6f6ab1 100644
--- a/mm/tiny-shmem.c
+++ b/mm/tiny-shmem.c
@@ -65,31 +65,25 @@ struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags)
if (!dentry)
goto put_memory;
- error = -ENOSPC;
- inode = ramfs_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0);
- if (!inode)
- goto put_dentry;
-
- d_instantiate(dentry, inode);
error = -ENFILE;
- file = alloc_file(shm_mnt, dentry, FMODE_WRITE | FMODE_READ,
- &ramfs_file_operations);
+ file = get_empty_filp();
if (!file)
goto put_dentry;
- inode->i_nlink = 0; /* It is unlinked */
-
- /* notify everyone as to the change of file size */
- error = do_truncate(dentry, size, 0, file);
- if (error < 0)
+ error = -ENOSPC;
+ inode = ramfs_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0);
+ if (!inode)
goto close_file;
+ d_instantiate(dentry, inode);
+ inode->i_size = size;
+ inode->i_nlink = 0; /* It is unlinked */
+ init_file(file, shm_mnt, dentry, FMODE_WRITE | FMODE_READ,
+ &ramfs_file_operations);
return file;
close_file:
put_filp(file);
- return ERR_PTR(error);
-
put_dentry:
dput(dentry);
put_memory:
diff --git a/mm/truncate.c b/mm/truncate.c
index 250505091d3..6650c1d878b 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -380,7 +380,7 @@ static int do_launder_page(struct address_space *mapping, struct page *page)
* Any pages which are found to be mapped into pagetables are unmapped prior to
* invalidation.
*
- * Returns -EIO if any pages could not be invalidated.
+ * Returns -EBUSY if any pages could not be invalidated.
*/
int invalidate_inode_pages2_range(struct address_space *mapping,
pgoff_t start, pgoff_t end)
@@ -440,7 +440,7 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
ret2 = do_launder_page(mapping, page);
if (ret2 == 0) {
if (!invalidate_complete_page2(mapping, page))
- ret2 = -EIO;
+ ret2 = -EBUSY;
}
if (ret2 < 0)
ret = ret2;
diff --git a/mm/vmstat.c b/mm/vmstat.c
index b0d08e667ec..d7826af2fb0 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -516,9 +516,26 @@ static void pagetypeinfo_showblockcount_print(struct seq_file *m,
continue;
page = pfn_to_page(pfn);
+#ifdef CONFIG_ARCH_FLATMEM_HAS_HOLES
+ /*
+ * Ordinarily, memory holes in flatmem still have a valid
+ * memmap for the PFN range. However, an architecture for
+ * embedded systems (e.g. ARM) can free up the memmap backing
+ * holes to save memory on the assumption the memmap is
+ * never used. The page_zone linkages are then broken even
+ * though pfn_valid() returns true. Skip the page if the
+ * linkages are broken. Even if this test passed, the impact
+ * is that the counters for the movable type are off but
+ * fragmentation monitoring is likely meaningless on small
+ * systems.
+ */
+ if (page_zone(page) != zone)
+ continue;
+#endif
mtype = get_pageblock_migratetype(page);
- count[mtype]++;
+ if (mtype < MIGRATE_TYPES)
+ count[mtype]++;
}
/* Print counts */
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-07 03:17:25 +0000