From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2F936158A27 for ; Tue, 9 Apr 2024 19:25:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712690754; cv=none; b=AJi4Q4twAw3qLxMGz3VEHjC5apD0AC9+S9PtfoaHinpYZi8OM5Bv310tMCNuDg9A3KuqYe3BQQc4YnAHLaIjJuXnR+6ZB2+4idZ9v/2zridXqr4bGAoOAT9P6F+qMaADV0+izr/r62bhhdW+cTWgwalbbBZ2GuCEYtn7F/Kxo4g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712690754; c=relaxed/simple; bh=Rq0Sd4YiurfGdBcBbt0nVkWNo0X3AhfDegChcctLqBs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=AThTtkCGGg0+azUh1tG2kTnhU9OFqLd4C8+wvo4LTc/5NCeCJH4tob/F9T54gmSvIcaKYcKcu5Fk+AgLMNW/e2fxx/Uds6LTDPBpGfPqK7ynb10iNZq4SRltFlC9adtiDST8sY5Yq9tt6f/bypzdgZ8vOSGfb1oA0c2+eEj/2YE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=V6rnAD5+; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="V6rnAD5+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1712690752; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=IN3zVkAYwXXWogoRwDYvxGTLC4K4Gwg+xwqZ7vjK29g=; b=V6rnAD5+tj8OwlMbs50UfN2fdNft8oH3YzTJvLt2sWYmsRVHZlu8VkQX0z5PR6LvwwAxUl cOUd+G0/CgPJHaDdoFHxiTtfwOMUlkNHg/OKCi3eLwV9aBHuQziDQ5kuTHqSUpFE4mJmjK f498NPYK2TCFsDF71f8JjDTh1PPaZLA= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-512-p7aYNzngOOiEyTZuHcjUMg-1; Tue, 09 Apr 2024 15:25:44 -0400 X-MC-Unique: p7aYNzngOOiEyTZuHcjUMg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id A0997830E7B; Tue, 9 Apr 2024 19:25:43 +0000 (UTC) Received: from t14s.redhat.com (unknown [10.39.192.106]) by smtp.corp.redhat.com (Postfix) with ESMTP id AD0CF419FA38; Tue, 9 Apr 2024 19:25:33 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linux-doc@vger.kernel.org, cgroups@vger.kernel.org, linux-sh@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, David Hildenbrand , Andrew Morton , "Matthew Wilcox (Oracle)" , Peter Xu , Ryan Roberts , Yin Fengwei , Yang Shi , Zi Yan , Jonathan Corbet , Hugh Dickins , Yoshinori Sato , Rich Felker , John Paul Adrian Glaubitz , Chris Zankel , Max Filippov , Muchun Song , Miaohe Lin , Naoya Horiguchi , Richard Chang Subject: [PATCH v1 11/18] mm/migrate: use folio_likely_mapped_shared() in add_page_for_migration() Date: Tue, 9 Apr 2024 21:22:54 +0200 Message-ID: <20240409192301.907377-12-david@redhat.com> In-Reply-To: <20240409192301.907377-1-david@redhat.com> References: <20240409192301.907377-1-david@redhat.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.2 We want to limit the use of page_mapcount() to the places where it is absolutely necessary. In add_page_for_migration(), we actually want to check if the folio is mapped shared, to reject such folios. So let's use folio_likely_mapped_shared() instead. For small folios, fully mapped THP, and hugetlb folios, there is no change. For partially mapped, shared THP, we should now do a better job at rejecting such folios. Signed-off-by: David Hildenbrand --- mm/migrate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/migrate.c b/mm/migrate.c index 285072bca29c..d87ce32645d4 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2140,7 +2140,7 @@ static int add_page_for_migration(struct mm_struct *mm, const void __user *p, goto out_putfolio; err = -EACCES; - if (page_mapcount(page) > 1 && !migrate_all) + if (folio_likely_mapped_shared(folio) && !migrate_all) goto out_putfolio; err = -EBUSY; -- 2.44.0