[PATCH 2/8] mm: hugetlb: don't drop hugetlb_lock around cma_release() call

From: Mike Kravetz <mike.kravetz@oracle.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: Roman Gushchin <guro@fb.com>, Michal Hocko <mhocko@suse.com>,
	Shakeel Butt <shakeelb@google.com>,
	Oscar Salvador <osalvador@suse.de>,
	David Hildenbrand <david@redhat.com>,
	Muchun Song <songmuchun@bytedance.com>,
	David Rientjes <rientjes@google.com>,
	Miaohe Lin <linmiaohe@huawei.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Matthew Wilcox <willy@infradead.org>,
	HORIGUCHI NAOYA <naoya.horiguchi@nec.com>,
	"Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
	Waiman Long <longman@redhat.com>, Peter Xu <peterx@redhat.com>,
	Mina Almasry <almasrymina@google.com>,
	Hillf Danton <hdanton@sina.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Mike Kravetz <mike.kravetz@oracle.com>
Subject: [PATCH 2/8] mm: hugetlb: don't drop hugetlb_lock around cma_release() call
Date: Wed, 24 Mar 2021 17:28:29 -0700	[thread overview]
Message-ID: <20210325002835.216118-3-mike.kravetz@oracle.com> (raw)
In-Reply-To: <20210325002835.216118-1-mike.kravetz@oracle.com>

From: Roman Gushchin <guro@fb.com>

Replace blocking cma_release() with a non-blocking cma_release_nowait()
call, so there is no more need to temporarily drop hugetlb_lock.

Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
---
 mm/hugetlb.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 408dbc08298a..f9ba63fc1747 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1258,10 +1258,11 @@ static void free_gigantic_page(struct page *page, unsigned int order)
 {
 	/*
 	 * If the page isn't allocated using the cma allocator,
-	 * cma_release() returns false.
+	 * cma_release_nowait() returns false.
 	 */
 #ifdef CONFIG_CMA
-	if (cma_release(hugetlb_cma[page_to_nid(page)], page, 1 << order))
+	if (cma_release_nowait(hugetlb_cma[page_to_nid(page)], page,
+			       1 << order))
 		return;
 #endif
 
@@ -1348,14 +1349,8 @@ static void update_and_free_page(struct hstate *h, struct page *page)
 	set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
 	set_page_refcounted(page);
 	if (hstate_is_gigantic(h)) {
-		/*
-		 * Temporarily drop the hugetlb_lock, because
-		 * we might block in free_gigantic_page().
-		 */
-		spin_unlock(&hugetlb_lock);
 		destroy_compound_gigantic_page(page, huge_page_order(h));
 		free_gigantic_page(page, huge_page_order(h));
-		spin_lock(&hugetlb_lock);
 	} else {
 		__free_pages(page, huge_page_order(h));
 	}
-- 
2.30.2

