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Mon, 3 Mar 2025 10:47:38 +0800 (CST) Received: from huawei.com (10.175.113.32) by kwepemg200013.china.huawei.com (7.202.181.64) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Mon, 3 Mar 2025 10:47:37 +0800 From: Liu Shixin To: Muchun Song , Andrew Morton , David Hildenbrand , Barry Song , Kefeng Wang , Peter Xu CC: , , Liu Shixin Subject: [PATCH] mm/hugetlb: update nr_huge_pages and surplus_huge_pages together Date: Mon, 3 Mar 2025 10:41:05 +0800 Message-ID: <20250303024105.990297-1-liushixin2@huawei.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-Originating-IP: [10.175.113.32] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To kwepemg200013.china.huawei.com (7.202.181.64) X-Rspamd-Server: rspam02 X-Stat-Signature: dnqrpzkco4cyrxhe1muuyf1ifq999d7y X-Rspamd-Queue-Id: 449041C0003 X-Rspam-User: X-HE-Tag: 1740970063-963886 X-HE-Meta: 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 K1NSrt/0 RFPfwRY1WKiIBjsvJF5sOgrDKr6WT+pgCrx3DYtYqnN6GWGAZ0Sh/bgRnPfrKV7NcLdPf5dREpCWKwtJbq1DUoNVkPh/KSnEGd+65D9Zsu4UeZddf3mO/Fw299EX9KkxMHFBoSqp3UwvNKjHH251OBmjgcxBeRU0A+UXYcxmNd3933yNCcL42L69zHGO0z8yTCZ3ODgnjoljdmukQ0E7CvUf65uTtSY4pBT5X X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: In alloc_surplus_hugetlb_folio(), we increase nr_huge_pages and surplus_huge_pages separately. In the middle window, if we set nr_hugepages to smaller and satisfy count < persistent_huge_pages(h), the surplus_huge_pages will be increased by adjust_pool_surplus(). After adding delay in the middle window, we can reproduce the problem easily by following step: 1. echo 3 > /proc/sys/vm/nr_overcommit_hugepages 2. mmap two hugepages. When nr_huge_pages=2 and surplus_huge_pages=1, goto step 3. 3. echo 0 > /proc/sys/vm/nr_huge_pages Finally, nr_huge_pages is less than surplus_huge_pages. Fixes: 0c397daea1d4 ("mm, hugetlb: further simplify hugetlb allocation API") Signed-off-by: Liu Shixin --- mm/hugetlb.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 9faa1034704ff..a900562ea7679 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2248,14 +2248,17 @@ static struct folio *alloc_surplus_hugetlb_folio(struct hstate *h, if (hstate_is_gigantic(h)) return NULL; + mutex_lock(&h->resize_lock); spin_lock_irq(&hugetlb_lock); if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) goto out_unlock; spin_unlock_irq(&hugetlb_lock); folio = alloc_fresh_hugetlb_folio(h, gfp_mask, nid, nmask); - if (!folio) + if (!folio) { + mutex_unlock(&h->resize_lock); return NULL; + } spin_lock_irq(&hugetlb_lock); /* @@ -2268,6 +2271,7 @@ static struct folio *alloc_surplus_hugetlb_folio(struct hstate *h, if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) { folio_set_hugetlb_temporary(folio); spin_unlock_irq(&hugetlb_lock); + mutex_unlock(&h->resize_lock); free_huge_folio(folio); return NULL; } @@ -2277,6 +2281,7 @@ static struct folio *alloc_surplus_hugetlb_folio(struct hstate *h, out_unlock: spin_unlock_irq(&hugetlb_lock); + mutex_unlock(&h->resize_lock); return folio; }