+ mmhugetlb-split-prep_new_huge_page-functionality.patch added to -mm tree

+ mmhugetlb-split-prep_new_huge_page-functionality.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm,hugetlb: split prep_new_huge_page functionality
has been added to the -mm tree.  Its filename is
     mmhugetlb-split-prep_new_huge_page-functionality.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mmhugetlb-split-prep_new_huge_page-functionality.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mmhugetlb-split-prep_new_huge_page-functionality.patch

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------------------------------------------------------
From: Oscar Salvador <osalvador@suse.de>
Subject: mm,hugetlb: split prep_new_huge_page functionality

Currently, prep_new_huge_page() performs two functions.  It sets the right
state for a new hugetlb, and increases the hstate's counters to account
for the new page.

Let us split its functionality into two separate functions, decoupling the
handling of the counters from initializing a hugepage.  The outcome is
having __prep_new_huge_page(), which only initializes the page , and
__prep_account_new_huge_page(), which adds the new page to the hstate's
counters.

This allows us to be able to set a hugetlb without having to worry about
the counter/locking.  It will prove useful in the next patch. 
prep_new_huge_page() still calls both functions.

Link: https://lkml.kernel.org/r/20210419075413.1064-5-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/hugetlb.c |   20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

--- a/mm/hugetlb.c~mmhugetlb-split-prep_new_huge_page-functionality
+++ a/mm/hugetlb.c
@@ -1484,16 +1484,30 @@ void free_huge_page(struct page *page)
 	}
 }
 
-static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
+/*
+ * Must be called with the hugetlb lock held
+ */
+static void __prep_account_new_huge_page(struct hstate *h, int nid)
+{
+	lockdep_assert_held(&hugetlb_lock);
+	h->nr_huge_pages++;
+	h->nr_huge_pages_node[nid]++;
+}
+
+static void __prep_new_huge_page(struct page *page)
 {
 	INIT_LIST_HEAD(&page->lru);
 	set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
 	hugetlb_set_page_subpool(page, NULL);
 	set_hugetlb_cgroup(page, NULL);
 	set_hugetlb_cgroup_rsvd(page, NULL);
+}
+
+static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
+{
+	__prep_new_huge_page(page);
 	spin_lock_irq(&hugetlb_lock);
-	h->nr_huge_pages++;
-	h->nr_huge_pages_node[nid]++;
+	__prep_account_new_huge_page(h, nid);
 	spin_unlock_irq(&hugetlb_lock);
 }
 
_

Patches currently in -mm which might be from osalvador@suse.de are

x86-vmemmap-drop-handling-of-4k-unaligned-vmemmap-range.patch
x86-vmemmap-drop-handling-of-1gb-vmemmap-ranges.patch
x86-vmemmap-handle-unpopulated-sub-pmd-ranges.patch
x86-vmemmap-handle-unpopulated-sub-pmd-ranges-fix.patch
x86-vmemmap-optimize-for-consecutive-sections-in-partial-populated-pmds.patch
mmpage_alloc-bail-out-earlier-on-enomem-in-alloc_contig_migrate_range.patch
mmcompaction-let-isolate_migratepages_rangeblock-return-error-codes.patch
mmhugetlb-drop-clearing-of-flag-from-prep_new_huge_page.patch
mmhugetlb-split-prep_new_huge_page-functionality.patch
mm-make-alloc_contig_range-handle-free-hugetlb-pages.patch
mm-make-alloc_contig_range-handle-in-use-hugetlb-pages.patch
mmpage_alloc-drop-unnecessary-checks-from-pfn_range_valid_contig.patch
drivers-base-memory-introduce-memory_block_onlineoffline.patch
mmmemory_hotplug-relax-fully-spanned-sections-check.patch
mmmemory_hotplug-allocate-memmap-from-the-added-memory-range.patch
acpimemhotplug-enable-mhp_memmap_on_memory-when-supported.patch
mmmemory_hotplug-add-kernel-boot-option-to-enable-memmap_on_memory.patch
x86-kconfig-introduce-arch_mhp_memmap_on_memory_enable.patch
arm64-kconfig-introduce-arch_mhp_memmap_on_memory_enable.patch