Merge branch 'akpm' (patches from Andrew)

Merge misc updates from Andrew Morton:
 "257 patches.

  Subsystems affected by this patch series: scripts, ocfs2, vfs, and
  mm (slab-generic, slab, slub, kconfig, dax, kasan, debug, pagecache,
  gup, swap, memcg, pagemap, mprotect, mremap, iomap, tracing, vmalloc,
  pagealloc, memory-failure, hugetlb, userfaultfd, vmscan, tools,
  memblock, oom-kill, hugetlbfs, migration, thp, readahead, nommu, ksm,
  vmstat, madvise, memory-hotplug, rmap, zsmalloc, highmem, zram,
  cleanups, kfence, and damon)"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (257 commits)
  mm/damon: remove return value from before_terminate callback
  mm/damon: fix a few spelling mistakes in comments and a pr_debug message
  mm/damon: simplify stop mechanism
  Docs/admin-guide/mm/pagemap: wordsmith page flags descriptions
  Docs/admin-guide/mm/damon/start: simplify the content
  Docs/admin-guide/mm/damon/start: fix a wrong link
  Docs/admin-guide/mm/damon/start: fix wrong example commands
  mm/damon/dbgfs: add adaptive_targets list check before enable monitor_on
  mm/damon: remove unnecessary variable initialization
  Documentation/admin-guide/mm/damon: add a document for DAMON_RECLAIM
  mm/damon: introduce DAMON-based Reclamation (DAMON_RECLAIM)
  selftests/damon: support watermarks
  mm/damon/dbgfs: support watermarks
  mm/damon/schemes: activate schemes based on a watermarks mechanism
  tools/selftests/damon: update for regions prioritization of schemes
  mm/damon/dbgfs: support prioritization weights
  mm/damon/vaddr,paddr: support pageout prioritization
  mm/damon/schemes: prioritize regions within the quotas
  mm/damon/selftests: support schemes quotas
  mm/damon/dbgfs: support quotas of schemes
  ...

1 files changed, 39 insertions, 33 deletions

diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index 0a2e417f83cb..09485dc5bd12 100644
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -20,7 +20,6 @@
  */
 
 #include <linux/gfp.h>
-#include <linux/interrupt.h>
 #include <linux/jhash.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
@@ -102,8 +101,8 @@ static bool init_stack_slab(void **prealloc)
 }
 
 /* Allocation of a new stack in raw storage */
-static struct stack_record *depot_alloc_stack(unsigned long *entries, int size,
-		u32 hash, void **prealloc, gfp_t alloc_flags)
+static struct stack_record *
+depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc)
 {
 	struct stack_record *stack;
 	size_t required_size = struct_size(stack, entries, size);
@@ -248,17 +247,28 @@ unsigned int stack_depot_fetch(depot_stack_handle_t handle,
 EXPORT_SYMBOL_GPL(stack_depot_fetch);
 
 /**
- * stack_depot_save - Save a stack trace from an array
+ * __stack_depot_save - Save a stack trace from an array
  *
  * @entries:		Pointer to storage array
  * @nr_entries:		Size of the storage array
  * @alloc_flags:	Allocation gfp flags
+ * @can_alloc:		Allocate stack slabs (increased chance of failure if false)
+ *
+ * Saves a stack trace from @entries array of size @nr_entries. If @can_alloc is
+ * %true, is allowed to replenish the stack slab pool in case no space is left
+ * (allocates using GFP flags of @alloc_flags). If @can_alloc is %false, avoids
+ * any allocations and will fail if no space is left to store the stack trace.
  *
- * Return: The handle of the stack struct stored in depot
+ * Context: Any context, but setting @can_alloc to %false is required if
+ *          alloc_pages() cannot be used from the current context. Currently
+ *          this is the case from contexts where neither %GFP_ATOMIC nor
+ *          %GFP_NOWAIT can be used (NMI, raw_spin_lock).
+ *
+ * Return: The handle of the stack struct stored in depot, 0 on failure.
  */
-depot_stack_handle_t stack_depot_save(unsigned long *entries,
-				      unsigned int nr_entries,
-				      gfp_t alloc_flags)
+depot_stack_handle_t __stack_depot_save(unsigned long *entries,
+					unsigned int nr_entries,
+					gfp_t alloc_flags, bool can_alloc)
 {
 	struct stack_record *found = NULL, **bucket;
 	depot_stack_handle_t retval = 0;
@@ -291,7 +301,7 @@ depot_stack_handle_t stack_depot_save(unsigned long *entries,
 	 * The smp_load_acquire() here pairs with smp_store_release() to
 	 * |next_slab_inited| in depot_alloc_stack() and init_stack_slab().
 	 */
-	if (unlikely(!smp_load_acquire(&next_slab_inited))) {
+	if (unlikely(can_alloc && !smp_load_acquire(&next_slab_inited))) {
 		/*
 		 * Zero out zone modifiers, as we don't have specific zone
 		 * requirements. Keep the flags related to allocation in atomic
@@ -309,9 +319,8 @@ depot_stack_handle_t stack_depot_save(unsigned long *entries,
 
 	found = find_stack(*bucket, entries, nr_entries, hash);
 	if (!found) {
-		struct stack_record *new =
-			depot_alloc_stack(entries, nr_entries,
-					  hash, &prealloc, alloc_flags);
+		struct stack_record *new = depot_alloc_stack(entries, nr_entries, hash, &prealloc);
+
 		if (new) {
 			new->next = *bucket;
 			/*
@@ -340,27 +349,24 @@ exit:
 fast_exit:
 	return retval;
 }
-EXPORT_SYMBOL_GPL(stack_depot_save);
-
-static inline int in_irqentry_text(unsigned long ptr)
-{
-	return (ptr >= (unsigned long)&__irqentry_text_start &&
-		ptr < (unsigned long)&__irqentry_text_end) ||
-		(ptr >= (unsigned long)&__softirqentry_text_start &&
-		 ptr < (unsigned long)&__softirqentry_text_end);
-}
+EXPORT_SYMBOL_GPL(__stack_depot_save);
 
-unsigned int filter_irq_stacks(unsigned long *entries,
-					     unsigned int nr_entries)
+/**
+ * stack_depot_save - Save a stack trace from an array
+ *
+ * @entries:		Pointer to storage array
+ * @nr_entries:		Size of the storage array
+ * @alloc_flags:	Allocation gfp flags
+ *
+ * Context: Contexts where allocations via alloc_pages() are allowed.
+ *          See __stack_depot_save() for more details.
+ *
+ * Return: The handle of the stack struct stored in depot, 0 on failure.
+ */
+depot_stack_handle_t stack_depot_save(unsigned long *entries,
+				      unsigned int nr_entries,
+				      gfp_t alloc_flags)
 {
-	unsigned int i;
-
-	for (i = 0; i < nr_entries; i++) {
-		if (in_irqentry_text(entries[i])) {
-			/* Include the irqentry function into the stack. */
-			return i + 1;
-		}
-	}
-	return nr_entries;
+	return __stack_depot_save(entries, nr_entries, alloc_flags, true);
 }
-EXPORT_SYMBOL_GPL(filter_irq_stacks);
+EXPORT_SYMBOL_GPL(stack_depot_save);