Commit d87f4a8f authored by Wei Yang's avatar Wei Yang Committed by Andrew Morton
Browse files

mm/huge_memory: only get folio_order() once during __folio_split() 

Before splitting folio, its order keeps the same.

It is only necessary to get folio_order() once.

Also rename order to old_order to represent the original folio order.

Link: https://lkml.kernel.org/r/20251010141142.1349-1-richard.weiyang@gmail.com


Signed-off-by: default avatarWei Yang <richard.weiyang@gmail.com>
Acked-by: default avatarLance Yang <lance.yang@linux.dev>
Acked-by: default avatarDavid Hildenbrand <david@redhat.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Barry Song <baohua@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent ac775677

mm/huge_memory.c

+9 −9
Original line number Diff line number Diff line
@@ -3682,7 +3682,7 @@ static int __folio_split(struct folio *folio, unsigned int new_order, 
	bool is_anon = folio_test_anon(folio);

	struct address_space *mapping = NULL;

	struct anon_vma *anon_vma = NULL;

	int order = folio_order(folio);

	int old_order = folio_order(folio);

	struct folio *new_folio, *next;

	int nr_shmem_dropped = 0;

	int remap_flags = 0;
@@ -3706,7 +3706,7 @@ static int __folio_split(struct folio *folio, unsigned int new_order, 
	if (!is_anon && !folio->mapping)

		return -EBUSY;



	if (new_order >= folio_order(folio))

	if (new_order >= old_order)

		return -EINVAL;



	if (uniform_split && !uniform_split_supported(folio, new_order, true))
@@ -3764,7 +3764,7 @@ static int __folio_split(struct folio *folio, unsigned int new_order, 


		if (uniform_split) {

			xas_set_order(&xas, folio->index, new_order);

			xas_split_alloc(&xas, folio, folio_order(folio), gfp);

			xas_split_alloc(&xas, folio, old_order, gfp);

			if (xas_error(&xas)) {

				ret = xas_error(&xas);

				goto out;
@@ -3820,12 +3820,12 @@ static int __folio_split(struct folio *folio, unsigned int new_order, 
		struct lruvec *lruvec;

		int expected_refs;



		if (folio_order(folio) > 1 &&

		if (old_order > 1 &&

		    !list_empty(&folio->_deferred_list)) {

			ds_queue->split_queue_len--;

			if (folio_test_partially_mapped(folio)) {

				folio_clear_partially_mapped(folio);

				mod_mthp_stat(folio_order(folio),

				mod_mthp_stat(old_order,

					MTHP_STAT_NR_ANON_PARTIALLY_MAPPED, -1);

			}

			/*
@@ -3954,7 +3954,7 @@ static int __folio_split(struct folio *folio, unsigned int new_order, 
	if (!ret && is_anon && !folio_is_device_private(folio))

		remap_flags = RMP_USE_SHARED_ZEROPAGE;



	remap_page(folio, 1 << order, remap_flags);

	remap_page(folio, 1 << old_order, remap_flags);



	/*

	 * Unlock all after-split folios except the one containing
@@ -3985,9 +3985,9 @@ static int __folio_split(struct folio *folio, unsigned int new_order, 
		i_mmap_unlock_read(mapping);

out:

	xas_destroy(&xas);

	if (order == HPAGE_PMD_ORDER)

	if (old_order == HPAGE_PMD_ORDER)

		count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED);

	count_mthp_stat(order, !ret ? MTHP_STAT_SPLIT : MTHP_STAT_SPLIT_FAILED);

	count_mthp_stat(old_order, !ret ? MTHP_STAT_SPLIT : MTHP_STAT_SPLIT_FAILED);

	return ret;

}