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Tue, 4 Mar 2025 16:45:14 +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; Tue, 4 Mar 2025 16:45:13 +0800 From: Liu Shixin To: Muchun Song , Andrew Morton , David Hildenbrand , Barry Song , Kefeng Wang , Peter Xu CC: , , Liu Shixin Subject: [PATCH v2] mm/hugetlb: update nr_huge_pages and surplus_huge_pages together Date: Tue, 4 Mar 2025 16:38:41 +0800 Message-ID: <20250304083841.283159-1-liushixin2@huawei.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-Originating-IP: [10.175.113.32] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To kwepemg200013.china.huawei.com (7.202.181.64) X-Rspamd-Queue-Id: F1D1340007 X-Stat-Signature: oi8knc3tz7swinpc64e3n7tunissjicg X-Rspam-User: X-Rspamd-Server: rspam05 X-HE-Tag: 1741077917-460083 X-HE-Meta: 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 hGVCmtAj ILsQM9rQkGfRULHlNxtPtY55xufuQwHHGNTd9EMBeXfeeL3C3AKhdBluI4AgaDBo0vPCS5NQIiv6OrOMudzjfHqF8I2cGf8ehfEgA7Z76N7fKsXiufsDAiA9GDb81C65DjKYEl3SuNWlu0KZdsWWf3iY0usDtcijWryDAaCAeDI0ydodtk5up6kRUaQPn31WgDXXjQpNIeVMlMqcRq4n94tiagk/2wwDQ4hh2 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. To fix the problem, call only_alloc_fresh_hugetlb_folio() instead and move down __prep_account_new_huge_page() into the hugetlb_lock. Fixes: 0c397daea1d4 ("mm, hugetlb: further simplify hugetlb allocation API") Signed-off-by: Liu Shixin --- mm/hugetlb.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 9faa1034704ff..0b02ea1c39e63 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2253,11 +2253,19 @@ static struct folio *alloc_surplus_hugetlb_folio(struct hstate *h, goto out_unlock; spin_unlock_irq(&hugetlb_lock); - folio = alloc_fresh_hugetlb_folio(h, gfp_mask, nid, nmask); + folio = only_alloc_fresh_hugetlb_folio(h, gfp_mask, nid, nmask, NULL); if (!folio) return NULL; + hugetlb_vmemmap_optimize_folio(h, folio); + spin_lock_irq(&hugetlb_lock); + /* + * Update nr_huge_pages and surplus_huge_pages together, + * otherwise it might confuse persistent_huge_pages() momentarily. + */ + __prep_account_new_huge_page(h, nid); + /* * We could have raced with the pool size change. * Double check that and simply deallocate the new page