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Thu, 18 Aug 2022 01:27:55 -0700 (PDT) From: Qi Zheng To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Qi Zheng Subject: [PATCH] mm: thp: remove redundant pgtable check in set_huge_zero_page() Date: Thu, 18 Aug 2022 16:27:48 +0800 Message-Id: <20220818082748.40021-1-zhengqi.arch@bytedance.com> X-Mailer: git-send-email 2.24.3 (Apple Git-128) MIME-Version: 1.0 ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1660817272; a=rsa-sha256; cv=none; b=zS9WdvtQcx19WXxgxAQOC0TVPztvGKKaX7SOkfPF6TGIkI+xdAPd5/Wr4psf5xueA7iZpB N4TP5QYCWasmHc2R2GTihHoOW+jJG0Mxr8Ya5mozXlruNApqgqoU0QEs0LDFSvqs+su/E8 wrZXatNZwFh/6A6eiAJzJmubKwc7K7k= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=bytedance-com.20210112.gappssmtp.com header.s=20210112 header.b=ZnFbnLt+; spf=pass (imf07.hostedemail.com: domain of zhengqi.arch@bytedance.com designates 209.85.166.46 as permitted sender) smtp.mailfrom=zhengqi.arch@bytedance.com; dmarc=pass (policy=none) header.from=bytedance.com ARC-Message-Signature: i=1; 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Otherwise we may receive the following warning when the mm exits: BUG: non-zero pgtables_bytes on freeing mm Now we can't observe the above warning since only do_huge_pmd_anonymous_page() invokes set_huge_zero_page() and the pgtable can not be NULL. Therefore, instead of moving mm_inc_nr_ptes() to the non-NULL branch of pgtable, it is better to remove the redundant pgtable check directly. Signed-off-by: Qi Zheng --- mm/huge_memory.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 83c47a989260..655da0b4fea0 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -770,8 +770,7 @@ static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, return; entry = mk_pmd(zero_page, vma->vm_page_prot); entry = pmd_mkhuge(entry); - if (pgtable) - pgtable_trans_huge_deposit(mm, pmd, pgtable); + pgtable_trans_huge_deposit(mm, pmd, pgtable); set_pmd_at(mm, haddr, pmd, entry); mm_inc_nr_ptes(mm); }