+ mm-memory_hotplug-override-memmap_on_memory-when-hugetlb_free_vmemmap=on.patch added to mm-unstable branch

* + mm-memory_hotplug-override-memmap_on_memory-when-hugetlb_free_vmemmap=on.patch added to mm-unstable branch
@ 2022-05-12 23:30 Andrew Morton
  0 siblings, 0 replies; 2+ messages in thread
From: Andrew Morton @ 2022-05-12 23:30 UTC (permalink / raw)
  To: mm-commits, yzaikin, osalvador, mike.kravetz, mcgrof, masahiroy,
	keescook, duanxiongchun, david, corbet, songmuchun, akpm


The patch titled
     Subject: mm: memory_hotplug: override memmap_on_memory when hugetlb_free_vmemmap=on
has been added to the -mm mm-unstable branch.  Its filename is
     mm-memory_hotplug-override-memmap_on_memory-when-hugetlb_free_vmemmap=on.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-memory_hotplug-override-memmap_on_memory-when-hugetlb_free_vmemmap=on.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: Muchun Song <songmuchun@bytedance.com>
Subject: mm: memory_hotplug: override memmap_on_memory when hugetlb_free_vmemmap=on

Optimizing HugeTLB vmemmap pages is not compatible with allocating memmap
on hot added memory.  If "hugetlb_free_vmemmap=on" and
memory_hotplug.memmap_on_memory" are both passed on the kernel command
line, optimizing hugetlb pages takes precedence.  However, the global
variable memmap_on_memory will still be set to 1, even though we will not
try to allocate memmap on hot added memory.

Also introduce mhp_memmap_on_memory() helper to move the definition of
"memmap_on_memory" to the scope of CONFIG_MHP_MEMMAP_ON_MEMORY.  In the
next patch, mhp_memmap_on_memory() will also be exported to be used in
hugetlb_vmemmap.c.

Link: https://lkml.kernel.org/r/20220512041142.39501-3-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memory_hotplug.c |   32 ++++++++++++++++++++++++++------
 1 file changed, 26 insertions(+), 6 deletions(-)

--- a/mm/memory_hotplug.c~mm-memory_hotplug-override-memmap_on_memory-when-hugetlb_free_vmemmap=on
+++ a/mm/memory_hotplug.c
@@ -42,14 +42,36 @@
 #include "internal.h"
 #include "shuffle.h"
 
+#ifdef CONFIG_MHP_MEMMAP_ON_MEMORY
+static int memmap_on_memory_set(const char *val, const struct kernel_param *kp)
+{
+	if (hugetlb_optimize_vmemmap_enabled())
+		return 0;
+	return param_set_bool(val, kp);
+}
+
+static const struct kernel_param_ops memmap_on_memory_ops = {
+	.flags	= KERNEL_PARAM_OPS_FL_NOARG,
+	.set	= memmap_on_memory_set,
+	.get	= param_get_bool,
+};
 
 /*
  * memory_hotplug.memmap_on_memory parameter
  */
 static bool memmap_on_memory __ro_after_init;
-#ifdef CONFIG_MHP_MEMMAP_ON_MEMORY
-module_param(memmap_on_memory, bool, 0444);
+module_param_cb(memmap_on_memory, &memmap_on_memory_ops, &memmap_on_memory, 0444);
 MODULE_PARM_DESC(memmap_on_memory, "Enable memmap on memory for memory hotplug");
+
+static inline bool mhp_memmap_on_memory(void)
+{
+	return memmap_on_memory;
+}
+#else
+static inline bool mhp_memmap_on_memory(void)
+{
+	return false;
+}
 #endif
 
 enum {
@@ -1289,9 +1311,7 @@ bool mhp_supports_memmap_on_memory(unsig
 	 *       altmap as an alternative source of memory, and we do not exactly
 	 *       populate a single PMD.
 	 */
-	return memmap_on_memory &&
-	       !hugetlb_optimize_vmemmap_enabled() &&
-	       IS_ENABLED(CONFIG_MHP_MEMMAP_ON_MEMORY) &&
+	return mhp_memmap_on_memory() &&
 	       size == memory_block_size_bytes() &&
 	       IS_ALIGNED(vmemmap_size, PMD_SIZE) &&
 	       IS_ALIGNED(remaining_size, (pageblock_nr_pages << PAGE_SHIFT));
@@ -2076,7 +2096,7 @@ static int __ref try_remove_memory(u64 s
 	 * We only support removing memory added with MHP_MEMMAP_ON_MEMORY in
 	 * the same granularity it was added - a single memory block.
 	 */
-	if (memmap_on_memory) {
+	if (mhp_memmap_on_memory()) {
 		nr_vmemmap_pages = walk_memory_blocks(start, size, NULL,
 						      get_nr_vmemmap_pages_cb);
 		if (nr_vmemmap_pages) {
_

Patches currently in -mm which might be from songmuchun@bytedance.com are

mm-hugetlb_vmemmap-disable-hugetlb_optimize_vmemmap-when-struct-page-crosses-page-boundaries.patch
mm-memory_hotplug-override-memmap_on_memory-when-hugetlb_free_vmemmap=on.patch
mm-hugetlb_vmemmap-use-kstrtobool-for-hugetlb_vmemmap-param-parsing.patch
mm-hugetlb_vmemmap-add-hugetlb_optimize_vmemmap-sysctl.patch


^ permalink raw reply	[flat|nested] 2+ messages in thread