From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 C48273314D9; Tue, 2 Jun 2026 04:21:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780374083; cv=none; b=srDYFG9KaXHpxzrAeuQWs9ddUS7qEA2nt6ygr6e1P4c4gDB2yuHlivOBEJH65lV0M7/mzzTOOj8qUZc7otHGPjQ0LKW2WmSiNZwG0PANfjuxRYzfvIqSSiU3GaF83EBbEUS3p9E+wxamg9yI8IpT3cTsfMcP8gaCJ/yQNX754yA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780374083; c=relaxed/simple; bh=H7kv1oVIGNpG97wf67N8yQnZ3vaX7YWckS62O7uo4+M=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=VNMKEb9osU+xq6H5+bL79qCk+M9Y+kkZUlH+3njGLu8+HvdxW/DCCr4pkfY8gcIQ3wprlXkoMExYWB2eI/snsmHOj5LkyDnywWBO5yzwWbcxOC3222U65r1ykH90MgGgrcO78NhnKU6hyAxG2/ubE2fW4S16EjiTa5YDgbiSQEg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Tpqk5/rq; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Tpqk5/rq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7C4351F00893; Tue, 2 Jun 2026 04:21:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780374082; bh=FG6uaynttx+7wL75om2XoMHvK6wM5vAOEXDW7jnm7sE=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=Tpqk5/rqismZ1mVczwfr+hex8navjFRtNT0GQdQ+HL8MmufzKlsGp2JNqYb1PgVLg tpeRX80+x+GwnujKarHY8k97sZSSJ5Y29Oka3hY/ApvhdWUUTcnYvDQI8ylGoYkCJ7 7G7M7+Yv627VnZqwvJJbpuX7fdkb5mj+N/MkoY2DxHlxHLm6hRcy1uVRBQwQ71TC33 DzEOH/c5EPU7OfNuGfMAaQ3cK++DKIVhYjkjbVxXEMRnR7a5v/6mDWphe9rLV1Iqoi 4uxzTGNruCd1kecpId37rMNDYPtUfdn61JqBbDPv+2SzQ1PkUdnbVMentg7sInUfbt BeouJ7KXMBo6A== Date: Tue, 2 Jun 2026 06:21:14 +0200 From: "Oscar Salvador (SUSE)" To: Dev Jain Cc: akpm@linux-foundation.org, liam@infradead.org, ljs@kernel.org, jgg@ziepe.ca, leon@kernel.org, david@kernel.org, shuah@kernel.org, vbabka@kernel.org, jannh@google.com, pfalcato@suse.de, rppt@kernel.org, surenb@google.com, mhocko@suse.com, balbirs@nvidia.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org, ryan.roberts@arm.com, anshuman.khandual@arm.com, stable@vger.kernel.org Subject: Re: [PATCH] fs/proc/task_mmu: do not warn on seeing non-migration pmd entry Message-ID: References: <20260529111704.1078346-1-dev.jain@arm.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260529111704.1078346-1-dev.jain@arm.com> On Fri, May 29, 2026 at 11:17:03AM +0000, Dev Jain wrote: > pagemap_pmd_range_thp() warns if a non-present PMD is not a migration > entry. This became false once device-private entries at the PMD level were > added. > > One can hit the warning by patching hmm-tests.c with the following: > > diff --git a/tools/testing/selftests/mm/hmm-tests.c b/tools/testing/selftests/mm/hmm-tests.c > index e1c8a679a4cf3..7f0a3384f3c5f 100644 > --- a/tools/testing/selftests/mm/hmm-tests.c > +++ b/tools/testing/selftests/mm/hmm-tests.c > @@ -209,6 +209,37 @@ static int hmm_dmirror_cmd(int fd, > return 0; > } > > +static int hmm_read_self_pagemap(void *addr, unsigned long npages, > + unsigned long page_size) > +{ > + const size_t entry_size = sizeof(uint64_t); > + const off_t offset = ((uintptr_t)addr / page_size) * entry_size; > + uint64_t *entries; > + ssize_t nread; > + int fd; > + > + entries = malloc(npages * entry_size); > + if (!entries) > + return -ENOMEM; > + > + fd = open("/proc/self/pagemap", O_RDONLY); > + if (fd < 0) { > + free(entries); > + return -errno; > + } > + > + nread = pread(fd, entries, npages * entry_size, offset); > + close(fd); > + free(entries); > + > + if (nread < 0) > + return -errno; > + if ((size_t)nread != npages * entry_size) > + return -EIO; > + > + return 0; > +} > + > static void hmm_buffer_free(struct hmm_buffer *buffer) > { > if (buffer == NULL) > @@ -2314,6 +2345,10 @@ TEST_F(hmm, migrate_anon_huge_fault) > ASSERT_EQ(ret, 0); > ASSERT_EQ(buffer->cpages, npages); > > + /* Exercise pagemap on a PMD device-private entry. */ > + ret = hmm_read_self_pagemap(buffer->ptr, npages, self->page_size); > + ASSERT_EQ(ret, 0); > + > /* Check what the device read. */ > for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i) > ASSERT_EQ(ptr[i], i); > > > Therefore, remove the stale migration-only assertion. > > Fixes: a30b48bf1b24 ("mm/migrate_device: implement THP migration of zone device pages") > Cc: stable@vger.kernel.org > Signed-off-by: Dev Jain LGTM, Reviewed-by: Oscar Salvador (SUSE) -- Oscar Salvador SUSE Labs