Merge tag 'mm-nonmm-stable-2024-03-14-09-36' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull non-MM updates from Andrew Morton:

 - Kuan-Wei Chiu has developed the well-named series "lib min_heap: Min
   heap optimizations".

 - Kuan-Wei Chiu has also sped up the library sorting code in the series
   "lib/sort: Optimize the number of swaps and comparisons".

 - Alexey Gladkov has added the ability for code running within an IPC
   namespace to alter its IPC and MQ limits. The series is "Allow to
   change ipc/mq sysctls inside ipc namespace".

 - Geert Uytterhoeven has contributed some dhrystone maintenance work in
   the series "lib: dhry: miscellaneous cleanups".

 - Ryusuke Konishi continues nilfs2 maintenance work in the series

	"nilfs2: eliminate kmap and kmap_atomic calls"
	"nilfs2: fix kernel bug at submit_bh_wbc()"

 - Nathan Chancellor has updated our build tools requirements in the
   series "Bump the minimum supported version of LLVM to 13.0.1".

 - Muhammad Usama Anjum continues with the selftests maintenance work in
   the series "selftests/mm: Improve run_vmtests.sh".

 - Oleg Nesterov has done some maintenance work against the signal code
   in the series "get_signal: minor cleanups and fix".

Plus the usual shower of singleton patches in various parts of the tree.
Please see the individual changelogs for details.

* tag 'mm-nonmm-stable-2024-03-14-09-36' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (77 commits)
  nilfs2: prevent kernel bug at submit_bh_wbc()
  nilfs2: fix failure to detect DAT corruption in btree and direct mappings
  ocfs2: enable ocfs2_listxattr for special files
  ocfs2: remove SLAB_MEM_SPREAD flag usage
  assoc_array: fix the return value in assoc_array_insert_mid_shortcut()
  buildid: use kmap_local_page()
  watchdog/core: remove sysctl handlers from public header
  nilfs2: use div64_ul() instead of do_div()
  mul_u64_u64_div_u64: increase precision by conditionally swapping a and b
  kexec: copy only happens before uchunk goes to zero
  get_signal: don't initialize ksig->info if SIGNAL_GROUP_EXIT/group_exec_task
  get_signal: hide_si_addr_tag_bits: fix the usage of uninitialized ksig
  get_signal: don't abuse ksig->info.si_signo and ksig->sig
  const_structs.checkpatch: add device_type
  Normalise "name (ad@dr)" MODULE_AUTHORs to "name <ad@dr>"
  dyndbg: replace kstrdup() + strchr() with kstrdup_and_replace()
  list: leverage list_is_head() for list_entry_is_head()
  nilfs2: MAINTAINERS: drop unreachable project mirror site
  smp: make __smp_processor_id() 0-argument macro
  fat: fix uninitialized field in nostale filehandles
  ...

1 files changed, 15 insertions, 5 deletions

diff --git a/lib/sort.c b/lib/sort.c
index b399bf10d675..a0509088f82a 100644
--- a/lib/sort.c
+++ b/lib/sort.c
@@ -215,6 +215,7 @@ void sort_r(void *base, size_t num, size_t size,
 	/* pre-scale counters for performance */
 	size_t n = num * size, a = (num/2) * size;
 	const unsigned int lsbit = size & -size;  /* Used to find parent */
+	size_t shift = 0;
 
 	if (!a)		/* num < 2 || size == 0 */
 		return;
@@ -242,12 +243,21 @@ void sort_r(void *base, size_t num, size_t size,
 	for (;;) {
 		size_t b, c, d;
 
-		if (a)			/* Building heap: sift down --a */
-			a -= size;
-		else if (n -= size)	/* Sorting: Extract root to --n */
+		if (a)			/* Building heap: sift down a */
+			a -= size << shift;
+		else if (n > 3 * size) { /* Sorting: Extract two largest elements */
+			n -= size;
 			do_swap(base, base + n, size, swap_func, priv);
-		else			/* Sort complete */
+			shift = do_cmp(base + size, base + 2 * size, cmp_func, priv) <= 0;
+			a = size << shift;
+			n -= size;
+			do_swap(base + a, base + n, size, swap_func, priv);
+		} else if (n > size) {	/* Sorting: Extract root */
+			n -= size;
+			do_swap(base, base + n, size, swap_func, priv);
+		} else	{		/* Sort complete */
 			break;
+		}
 
 		/*
 		 * Sift element at "a" down into heap.  This is the
@@ -262,7 +272,7 @@ void sort_r(void *base, size_t num, size_t size,
 		 * average, 3/4 worst-case.)
 		 */
 		for (b = a; c = 2*b + size, (d = c + size) < n;)
-			b = do_cmp(base + c, base + d, cmp_func, priv) >= 0 ? c : d;
+			b = do_cmp(base + c, base + d, cmp_func, priv) > 0 ? c : d;
 		if (d == n)	/* Special case last leaf with no sibling */
 			b = c;