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[2003:cb:c706:5000:4fff:1dd6:7868:a36]) by smtp.gmail.com with ESMTPSA id u8-20020a5d5148000000b0022e04bfa661sm10918272wrt.59.2022.10.04.05.20.07 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 04 Oct 2022 05:20:07 -0700 (PDT) Message-ID: <9ac201f6-6295-c606-305f-00cafd099313@redhat.com> Date: Tue, 4 Oct 2022 14:20:06 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.3.0 Subject: Re: [PATCH v2 2/3] mm/hugetlb: Use hugetlb_pte_stable in migration race check To: Peter Xu , linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Andrew Morton , Nadav Amit , Mike Kravetz , Andrea Arcangeli , Axel Rasmussen , Mike Rapoport References: <20221004003705.497782-1-peterx@redhat.com> <20221004003705.497782-3-peterx@redhat.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: <20221004003705.497782-3-peterx@redhat.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1664886011; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=7vtxTBoFKlQS05YjdzP5SgsxHgg1muVOwrB43RAkVuE=; b=h2m7t1/wWTTRlFcYPLgF/Zx8vpE0KPmlNqgOUxe1OAIDUhWhQ6sC6dTlcCcCeplGLkpfaa WA9Nrrcx3rn9vprwwk9UNZVrVKWoiK1zICZ+7enR9v+j3y+QlIvMOf2CqfAtvn7rGuaPTj bjLnLI9mxKEEyB7Me6g7L/v6zdgCBVs= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=ZvrTzcbL; spf=pass (imf18.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1664886011; a=rsa-sha256; cv=none; b=Zg9qlMxdVvdqF7+vkXMmg4GzMMbhyDFVrs3/ZNV2o528hOsU6y90iVK2jBTbsOpr0Kx9nQ pS/BeJKRawFhU9b7/mGFdXxrmIeJ5IlGsFrKxTHo8ZJEZeYWEGUsSVUv+Q7UicOcYGqILO 6nrX+/5t+qxYRl8cZZKZy4wwWBW4dDg= X-Rspamd-Queue-Id: AE4171C001B Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=ZvrTzcbL; spf=pass (imf18.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Rspamd-Server: rspam06 X-Rspam-User: X-Stat-Signature: r8un3yrehdq3yjdpmqa5b87h7osecao6 X-HE-Tag: 1664886011-682439 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: On 04.10.22 02:37, Peter Xu wrote: > After hugetlb_pte_stable() introduced, we can also rewrite the migration > race condition against page allocation to use the new helper too. > > Signed-off-by: Peter Xu > --- > mm/hugetlb.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index fa3fcdb0c4b8..e762c5369a6f 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -5620,11 +5620,10 @@ static vm_fault_t hugetlb_no_page(struct mm_struct *mm, > * here. Before returning error, get ptl and make > * sure there really is no pte entry. > */ > - ptl = huge_pte_lock(h, mm, ptep); > - ret = 0; > - if (huge_pte_none(huge_ptep_get(ptep))) > + if (hugetlb_pte_stable(h, mm, ptep, old_pte)) > ret = vmf_error(PTR_ERR(page)); > - spin_unlock(ptl); > + else > + ret = 0; > goto out; > } > clear_huge_page(page, address, pages_per_huge_page(h)); Reviewed-by: David Hildenbrand -- Thanks, David / dhildenb