Merge branch 'akpm' (patches from Andrew)

Merge more fixes from Andrew Morton:
 "17 fixes"

Mostly mm fixes and one ocfs2 locking fix.

* emailed patches from Andrew Morton <[email protected]>:
  mm: memcontrol: fix network errors from failing __GFP_ATOMIC charges
  mm/memory_hotplug: fix updating the node span
  scripts/gdb: fix debugging modules compiled with hot/cold partitioning
  mm: slab: make page_cgroup_ino() to recognize non-compound slab pages properly
  MAINTAINERS: update information for "MEMORY MANAGEMENT"
  dump_stack: avoid the livelock of the dump_lock
  zswap: add Vitaly to the maintainers list
  mm/page_alloc.c: ratelimit allocation failure warnings more aggressively
  mm/khugepaged: fix might_sleep() warn with CONFIG_HIGHPTE=y
  mm, vmstat: reduce zone->lock holding time by /proc/pagetypeinfo
  mm, vmstat: hide /proc/pagetypeinfo from normal users
  mm/mmu_notifiers: use the right return code for WARN_ON
  ocfs2: protect extent tree in ocfs2_prepare_inode_for_write()
  mm: thp: handle page cache THP correctly in PageTransCompoundMap
  mm, meminit: recalculate pcpu batch and high limits after init completes
  mm/gup_benchmark: fix MAP_HUGETLB case
  mm: memcontrol: fix NULL-ptr deref in percpu stats flush

MAINTAINERS

@@ -10519,8 +10519,12 @@ F:	mm/memblock.c
 F:	Documentation/core-api/boot-time-mm.rst
 
 MEMORY MANAGEMENT
+M:	Andrew Morton <[email protected]>
 L:	[email protected]
 W:	http://www.linux-mm.org
+T:	quilt https://ozlabs.org/~akpm/mmotm/
+T:	quilt https://ozlabs.org/~akpm/mmots/
+T:	git git://github.com/hnaz/linux-mm.git
 S:	Maintained
 F:	include/linux/mm.h
 F:	include/linux/gfp.h
@@ -18034,6 +18038,7 @@ F:	Documentation/vm/zsmalloc.rst
 ZSWAP COMPRESSED SWAP CACHING
 M:	Seth Jennings <[email protected]>
 M:	Dan Streetman <[email protected]>
+M:	Vitaly Wool <[email protected]>
 L:	[email protected]
 S:	Maintained
 F:	mm/zswap.c

fs/ocfs2/file.c

@@ -2098,53 +2098,89 @@ static int ocfs2_is_io_unaligned(struct inode *inode, size_t count, loff_t pos)
 	return 0;
 }
 
-static int ocfs2_prepare_inode_for_refcount(struct inode *inode,
-					    struct file *file,
-					    loff_t pos, size_t count,
-					    int *meta_level)
+static int ocfs2_inode_lock_for_extent_tree(struct inode *inode,
+					    struct buffer_head **di_bh,
+					    int meta_level,
+					    int overwrite_io,
+					    int write_sem,
+					    int wait)
 {
-	int ret;
-	struct buffer_head *di_bh = NULL;
-	u32 cpos = pos >> OCFS2_SB(inode->i_sb)->s_clustersize_bits;
-	u32 clusters =
-		ocfs2_clusters_for_bytes(inode->i_sb, pos + count) - cpos;
+	int ret = 0;
 
-	ret = ocfs2_inode_lock(inode, &di_bh, 1);
-	if (ret) {
-		mlog_errno(ret);
+	if (wait)
+		ret = ocfs2_inode_lock(inode, NULL, meta_level);
+	else
+		ret = ocfs2_try_inode_lock(inode,
+			overwrite_io ? NULL : di_bh, meta_level);
+	if (ret < 0)
 		goto out;
+
+	if (wait) {
+		if (write_sem)
+			down_write(&OCFS2_I(inode)->ip_alloc_sem);
+		else
+			down_read(&OCFS2_I(inode)->ip_alloc_sem);
+	} else {
+		if (write_sem)
+			ret = down_write_trylock(&OCFS2_I(inode)->ip_alloc_sem);
+		else
+			ret = down_read_trylock(&OCFS2_I(inode)->ip_alloc_sem);
+
+		if (!ret) {
+			ret = -EAGAIN;
+			goto out_unlock;
+		}
 	}
 
-	*meta_level = 1;
+	return ret;
 
-	ret = ocfs2_refcount_cow(inode, di_bh, cpos, clusters, UINT_MAX);
-	if (ret)
-		mlog_errno(ret);
+out_unlock:
+	brelse(*di_bh);
+	ocfs2_inode_unlock(inode, meta_level);
 out:
-	brelse(di_bh);
 	return ret;
 }
 
+static void ocfs2_inode_unlock_for_extent_tree(struct inode *inode,
+					       struct buffer_head **di_bh,
+					       int meta_level,
+					       int write_sem)
+{
+	if (write_sem)
+		up_write(&OCFS2_I(inode)->ip_alloc_sem);
+	else
+		up_read(&OCFS2_I(inode)->ip_alloc_sem);
+
+	brelse(*di_bh);
+	*di_bh = NULL;
+
+	if (meta_level >= 0)
+		ocfs2_inode_unlock(inode, meta_level);
+}
+
 static int ocfs2_prepare_inode_for_write(struct file *file,
 					 loff_t pos, size_t count, int wait)
 {
 	int ret = 0, meta_level = 0, overwrite_io = 0;
+	int write_sem = 0;
 	struct dentry *dentry = file->f_path.dentry;
 	struct inode *inode = d_inode(dentry);
 	struct buffer_head *di_bh = NULL;
+	u32 cpos;
+	u32 clusters;
 
 	/*
 	 * We start with a read level meta lock and only jump to an ex
 	 * if we need to make modifications here.
 	 */
 	for(;;) {
-		if (wait)
-			ret = ocfs2_inode_lock(inode, NULL, meta_level);
-		else
-			ret = ocfs2_try_inode_lock(inode,
-				overwrite_io ? NULL : &di_bh, meta_level);
+		ret = ocfs2_inode_lock_for_extent_tree(inode,
+						       &di_bh,
+						       meta_level,
+						       overwrite_io,
+						       write_sem,
+						       wait);
 		if (ret < 0) {
-			meta_level = -1;
 			if (ret != -EAGAIN)
 				mlog_errno(ret);
 			goto out;
@@ -2156,15 +2192,8 @@ static int ocfs2_prepare_inode_for_write(struct file *file,
 		 */
 		if (!wait && !overwrite_io) {
 			overwrite_io = 1;
-			if (!down_read_trylock(&OCFS2_I(inode)->ip_alloc_sem)) {
-				ret = -EAGAIN;
-				goto out_unlock;
-			}
 
 			ret = ocfs2_overwrite_io(inode, di_bh, pos, count);
-			brelse(di_bh);
-			di_bh = NULL;
-			up_read(&OCFS2_I(inode)->ip_alloc_sem);
 			if (ret < 0) {
 				if (ret != -EAGAIN)
 					mlog_errno(ret);
@@ -2183,7 +2212,10 @@ static int ocfs2_prepare_inode_for_write(struct file *file,
 		 * set inode->i_size at the end of a write. */
 		if (should_remove_suid(dentry)) {
 			if (meta_level == 0) {
-				ocfs2_inode_unlock(inode, meta_level);
+				ocfs2_inode_unlock_for_extent_tree(inode,
+								   &di_bh,
+								   meta_level,
+								   write_sem);
 				meta_level = 1;
 				continue;
 			}
@@ -2197,18 +2229,32 @@ static int ocfs2_prepare_inode_for_write(struct file *file,
 
 		ret = ocfs2_check_range_for_refcount(inode, pos, count);
 		if (ret == 1) {
-			ocfs2_inode_unlock(inode, meta_level);
-			meta_level = -1;
-
-			ret = ocfs2_prepare_inode_for_refcount(inode,
-							       file,
-							       pos,
-							       count,
-							       &meta_level);
+			ocfs2_inode_unlock_for_extent_tree(inode,
+							   &di_bh,
+							   meta_level,
+							   write_sem);
+			ret = ocfs2_inode_lock_for_extent_tree(inode,
+							       &di_bh,
+							       meta_level,
+							       overwrite_io,
+							       1,
+							       wait);
+			write_sem = 1;
+			if (ret < 0) {
+				if (ret != -EAGAIN)
+					mlog_errno(ret);
+				goto out;
+			}
+
+			cpos = pos >> OCFS2_SB(inode->i_sb)->s_clustersize_bits;
+			clusters =
+				ocfs2_clusters_for_bytes(inode->i_sb, pos + count) - cpos;
+			ret = ocfs2_refcount_cow(inode, di_bh, cpos, clusters, UINT_MAX);
 		}
 
 		if (ret < 0) {
-			mlog_errno(ret);
+			if (ret != -EAGAIN)
+				mlog_errno(ret);
 			goto out_unlock;
 		}
 
@@ -2219,10 +2265,10 @@ static int ocfs2_prepare_inode_for_write(struct file *file,
 	trace_ocfs2_prepare_inode_for_write(OCFS2_I(inode)->ip_blkno,
 					    pos, count, wait);
 
-	brelse(di_bh);
-
-	if (meta_level >= 0)
-		ocfs2_inode_unlock(inode, meta_level);
+	ocfs2_inode_unlock_for_extent_tree(inode,
+					   &di_bh,
+					   meta_level,
+					   write_sem);
 
 out:
 	return ret;

include/linux/mm.h

@@ -695,11 +695,6 @@ static inline void *kvcalloc(size_t n, size_t size, gfp_t flags)
 
 extern void kvfree(const void *addr);
 
-static inline atomic_t *compound_mapcount_ptr(struct page *page)
-{
-	return &page[1].compound_mapcount;
-}
-
 static inline int compound_mapcount(struct page *page)
 {
 	VM_BUG_ON_PAGE(!PageCompound(page), page);

include/linux/mm_types.h

@@ -221,6 +221,11 @@ struct page {
 #endif
 } _struct_page_alignment;
 
+static inline atomic_t *compound_mapcount_ptr(struct page *page)
+{
+	return &page[1].compound_mapcount;
+}
+
 /*
  * Used for sizing the vmemmap region on some architectures
  */

include/linux/page-flags.h

@@ -622,12 +622,28 @@ static inline int PageTransCompound(struct page *page)
  *
  * Unlike PageTransCompound, this is safe to be called only while
  * split_huge_pmd() cannot run from under us, like if protected by the
- * MMU notifier, otherwise it may result in page->_mapcount < 0 false
+ * MMU notifier, otherwise it may result in page->_mapcount check false
  * positives.
+ *
+ * We have to treat page cache THP differently since every subpage of it
+ * would get _mapcount inc'ed once it is PMD mapped.  But, it may be PTE
+ * mapped in the current process so comparing subpage's _mapcount to
+ * compound_mapcount to filter out PTE mapped case.
  */
 static inline int PageTransCompoundMap(struct page *page)
 {
-	return PageTransCompound(page) && atomic_read(&page->_mapcount) < 0;
+	struct page *head;
+
+	if (!PageTransCompound(page))
+		return 0;
+
+	if (PageAnon(page))
+		return atomic_read(&page->_mapcount) < 0;
+
+	head = compound_head(page);
+	/* File THP is PMD mapped and not PTE mapped */
+	return atomic_read(&page->_mapcount) ==
+	       atomic_read(compound_mapcount_ptr(head));
 }
 
 /*

lib/dump_stack.c

@@ -106,7 +106,12 @@ asmlinkage __visible void dump_stack(void)
 		was_locked = 1;
 	} else {
 		local_irq_restore(flags);
-		cpu_relax();
+		/*
+		 * Wait for the lock to release before jumping to
+		 * atomic_cmpxchg() in order to mitigate the thundering herd
+		 * problem.
+		 */
+		do { cpu_relax(); } while (atomic_read(&dump_lock) != -1);
 		goto retry;
 	}
 

mm/khugepaged.c

@@ -1028,12 +1028,13 @@ static void collapse_huge_page(struct mm_struct *mm,
 
 	anon_vma_lock_write(vma->anon_vma);
 
-	pte = pte_offset_map(pmd, address);
-	pte_ptl = pte_lockptr(mm, pmd);
-
 	mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, NULL, mm,
 				address, address + HPAGE_PMD_SIZE);
 	mmu_notifier_invalidate_range_start(&range);
+
+	pte = pte_offset_map(pmd, address);
+	pte_ptl = pte_lockptr(mm, pmd);
+
 	pmd_ptl = pmd_lock(mm, pmd); /* probably unnecessary */
 	/*
 	 * After this gup_fast can't run anymore. This also removes

mm/memcontrol.c

@@ -484,7 +484,7 @@ ino_t page_cgroup_ino(struct page *page)
 	unsigned long ino = 0;
 
 	rcu_read_lock();
-	if (PageHead(page) && PageSlab(page))
+	if (PageSlab(page) && !PageTail(page))
 		memcg = memcg_from_slab_page(page);
 	else
 		memcg = READ_ONCE(page->mem_cgroup);
@@ -2534,6 +2534,15 @@ static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
 		goto retry;
 	}
 
+	/*
+	 * Memcg doesn't have a dedicated reserve for atomic
+	 * allocations. But like the global atomic pool, we need to
+	 * put the burden of reclaim on regular allocation requests
+	 * and let these go through as privileged allocations.
+	 */
+	if (gfp_mask & __GFP_ATOMIC)
+		goto force;
+
 	/*
 	 * Unlike in global OOM situations, memcg is not in a physical
 	 * memory shortage.  Allow dying and OOM-killed tasks to
@@ -5014,12 +5023,6 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg)
 {
 	int node;
 
-	/*
-	 * Flush percpu vmstats and vmevents to guarantee the value correctness
-	 * on parent's and all ancestor levels.
-	 */
-	memcg_flush_percpu_vmstats(memcg, false);
-	memcg_flush_percpu_vmevents(memcg);
 	for_each_node(node)
 		free_mem_cgroup_per_node_info(memcg, node);
 	free_percpu(memcg->vmstats_percpu);
@@ -5030,6 +5033,12 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg)
 static void mem_cgroup_free(struct mem_cgroup *memcg)
 {
 	memcg_wb_domain_exit(memcg);
+	/*
+	 * Flush percpu vmstats and vmevents to guarantee the value correctness
+	 * on parent's and all ancestor levels.
+	 */
+	memcg_flush_percpu_vmstats(memcg, false);
+	memcg_flush_percpu_vmevents(memcg);
 	__mem_cgroup_free(memcg);
 }
 

mm/memory_hotplug.c

@@ -447,6 +447,14 @@ static void update_pgdat_span(struct pglist_data *pgdat)
 					     zone->spanned_pages;
 
 		/* No need to lock the zones, they can't change. */
+		if (!zone->spanned_pages)
+			continue;
+		if (!node_end_pfn) {
+			node_start_pfn = zone->zone_start_pfn;
+			node_end_pfn = zone_end_pfn;
+			continue;
+		}
+
 		if (zone_end_pfn > node_end_pfn)
 			node_end_pfn = zone_end_pfn;
 		if (zone->zone_start_pfn < node_start_pfn)

mm/mmu_notifier.c

@@ -180,7 +180,7 @@ int __mmu_notifier_invalidate_range_start(struct mmu_notifier_range *range)
 					mn->ops->invalidate_range_start, _ret,
 					!mmu_notifier_range_blockable(range) ? "non-" : "");
 				WARN_ON(mmu_notifier_range_blockable(range) ||
-					ret != -EAGAIN);
+					_ret != -EAGAIN);
 				ret = _ret;
 			}
 		}