From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 3A4CB384239 for ; Thu, 16 Apr 2026 23:53:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776383580; cv=none; b=U9o9IKi6N3rx6LT5aNX1OVnuFOz28LCWCtv6ARYEyp/kDm08NCleik+3sPKduzk0jMSukto0vgdeil2Pf2RJtDY05BnF60pGfi1pUEagyO2YPAAcWX9WZIY7WGpd4K5K4SFQ73Lr4ZQyQcl8qvfcBUCecyQl/WS2y8NL46X1BRM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776383580; c=relaxed/simple; bh=9SWONO6EtK9WNbOOzpbgwmw3MwdSQ2Hg0jtMrKPGzDM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=geis0f6j5Ze1tnt6zUbP4yccrcGxwwUa4WZkGujY5JkjBqUeOruY+EnRrs2xMzelqbb46C18ge2evogSsjoc1TrTYnU/6FqK8v67inyDna6SWsrNLzezVBms5VGogMV68rVKmZWIj/5qEVC6sgf2Ax+kTdL+Y2LIh1t2j5rZd6s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=EvIXvpzK; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="EvIXvpzK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 692D4C2BCAF; Thu, 16 Apr 2026 23:52:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776383579; bh=9SWONO6EtK9WNbOOzpbgwmw3MwdSQ2Hg0jtMrKPGzDM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EvIXvpzKVVjOwwTpybD1uSPUoLx6n3xoVIdmWsQG3W27VAdCTj5AQipNMzjCDsA0n TpaXtV9msRMvTnZQHkBfjIk7scNcAH+1p4HH90Wk9V7qdpbhN0TDAkKd4+xdvAgBpe SkuNE9P5MDxqhDr1u7YuNmIB5NMKNCLC/0/1DjIiuKHtfbvanebyms9Yu6q6XefFra 5xudcG0atI/nE4oV7YxTCC+HZG6pbT5IxwJYhMDHDp4utIIYqdthQ2GQHVWABv2AJT bpkqUD/JSVbNpzhnPlTmlGlmT9t8CDi+zUGRmHvnsNzmH145M5U5x1ZbtpXvj9iQwC aCSPZS0ZomZ/Q== From: SeongJae Park To: "David Hildenbrand (Arm)" Cc: SeongJae Park , Sunny Patel , Andrew Morton , Zi Yan , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/migrate_device: Cleanup up PMD Checks and warnings Date: Thu, 16 Apr 2026 16:52:51 -0700 Message-ID: <20260416235252.58831-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Thu, 16 Apr 2026 21:44:15 +0200 "David Hildenbrand (Arm)" wrote: > On 4/14/26 16:13, Sunny Patel wrote: [...] > > @@ -865,12 +864,13 @@ static int migrate_vma_insert_huge_pmd_page(struct migrate_vma *migrate, > > if (userfaultfd_missing(vma)) > > goto unlock_abort; > > > > - if (!pmd_none(*pmdp)) { > > + if (pmd_present(*pmdp)) { > > if (!is_huge_zero_pmd(*pmdp)) > > goto unlock_abort; > > flush = true; > > - } else if (!pmd_none(*pmdp)) > > + } else if (!pmd_none(*pmdp)) { > > goto unlock_abort; > > + } > > > > add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); > > folio_add_new_anon_rmap(folio, vma, addr, RMAP_EXCLUSIVE); > > is_huge_zero_pmd() checks pmd_present(), so we didn't have a bug before. > > We could also do: > > if (is_huge_zero_pmd(*pmdp)) { > flush = true; > } else if (!pmd_none(*pmdp)) { > goto unlock_abort; > } Then we could even further remove the braces and reduce one more line, nice! Thanks, SJ [...]