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28 Jan 2020 16:28:28 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,375,1574150400"; d="scan'208";a="229456426" Received: from richard.sh.intel.com (HELO localhost) ([10.239.159.54]) by orsmga003.jf.intel.com with ESMTP; 28 Jan 2020 16:28:25 -0800 Date: Wed, 29 Jan 2020 08:28:38 +0800 From: Wei Yang To: Dmitry Osipenko Cc: Wei Yang , Russell King - ARM Linux , akpm@linux-foundation.org, dan.j.williams@intel.com, aneesh.kumar@linux.ibm.com, kirill@shutemov.name, yang.shi@linux.alibaba.com, thellstrom@vmware.com, Thierry Reding , Jon Hunter , linux-kernel@vger.kernel.org, linux-mm@kvack.org, "linux-tegra@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH 3/5] mm/mremap: use pmd_addr_end to calculate next in move_page_tables() Message-ID: <20200129002838.GA12835@richard> Reply-To: Wei Yang References: <20200117232254.2792-1-richardw.yang@linux.intel.com> <20200117232254.2792-4-richardw.yang@linux.intel.com> <7147774a-14e9-4ff3-1548-4565f0d214d5@gmail.com> <20200128004301.GD20624@richard> <20200128232907.GA11467@richard> <27b70b0c-7945-cc85-8321-d9e4b6f17865@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <27b70b0c-7945-cc85-8321-d9e4b6f17865@gmail.com> User-Agent: Mutt/1.9.4 (2018-02-28) Content-Transfer-Encoding: quoted-printable 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 Wed, Jan 29, 2020 at 02:35:25AM +0300, Dmitry Osipenko wrote: >29.01.2020 02:29, Wei Yang =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >> On Tue, Jan 28, 2020 at 06:59:48PM +0300, Dmitry Osipenko wrote: >>> 28.01.2020 03:43, Wei Yang =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >>>> On Sun, Jan 26, 2020 at 05:47:57PM +0300, Dmitry Osipenko wrote: >>>>> 18.01.2020 02:22, Wei Yang =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >>>>>> Use the general helper instead of do it by hand. >>>>>> >>>>>> Signed-off-by: Wei Yang >>>>>> --- >>>>>> mm/mremap.c | 7 ++----- >>>>>> 1 file changed, 2 insertions(+), 5 deletions(-) >>>>>> >>>>>> diff --git a/mm/mremap.c b/mm/mremap.c >>>>>> index c2af8ba4ba43..a258914f3ee1 100644 >>>>>> --- a/mm/mremap.c >>>>>> +++ b/mm/mremap.c >>>>>> @@ -253,11 +253,8 @@ unsigned long move_page_tables(struct vm_area= _struct *vma, >>>>>> =20 >>>>>> for (; old_addr < old_end; old_addr +=3D extent, new_addr +=3D e= xtent) { >>>>>> cond_resched(); >>>>>> - next =3D (old_addr + PMD_SIZE) & PMD_MASK; >>>>>> - /* even if next overflowed, extent below will be ok */ >>>>>> + next =3D pmd_addr_end(old_addr, old_end); >>>>>> extent =3D next - old_addr; >>>>>> - if (extent > old_end - old_addr) >>>>>> - extent =3D old_end - old_addr; >>>>>> old_pmd =3D get_old_pmd(vma->vm_mm, old_addr); >>>>>> if (!old_pmd) >>>>>> continue; >>>>>> @@ -301,7 +298,7 @@ unsigned long move_page_tables(struct vm_area_= struct *vma, >>>>>> =20 >>>>>> if (pte_alloc(new_vma->vm_mm, new_pmd)) >>>>>> break; >>>>>> - next =3D (new_addr + PMD_SIZE) & PMD_MASK; >>>>>> + next =3D pmd_addr_end(new_addr, new_addr + len); >>>>>> if (extent > next - new_addr) >>>>>> extent =3D next - new_addr; >>>>>> move_ptes(vma, old_pmd, old_addr, old_addr + extent, new_vma, >>>>>> >>>>> >>>>> Hello Wei, >>>>> >>>>> Starting with next-20200122, I'm seeing the following in KMSG on NV= IDIA >>>>> Tegra (ARM32): >>>>> >>>>> BUG: Bad rss-counter state mm:(ptrval) type:MM_ANONPAGES val:190 >>>>> >>>> >>>> Thanks. >>>> >>>> Would you mind letting me know which case you are testing? >>> >>> Nothing special, systemd starts to fall apart during boot. >>> >>>> Or the special thing is 32-bit platform? >>> I have a limited knowledge about mm/, so can't provide detailed expla= nation. >>> >>> Please take a look at this: >>> >>> [1] >>> https://elixir.bootlin.com/linux/v5.5/source/arch/arm/include/asm/pgt= able-2level.h#L210 >>> >>> [2] >>> https://elixir.bootlin.com/linux/v5.5/source/include/asm-generic/pgta= ble.h#L549 >>> >>> [3] >>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/co= mmit/?id=3Dc0ba10b512eb2e2a3888b6e6cc0e089f5e7a191b >>=20 >> Thanks, I see the difference here. >>=20 >> If this is the case, we can't use pmd_addr_end() to simplify the calcu= lation. >> This changes the behavior. >>=20 >> I would prepare another patch set to fix this. Would you mind helping = me >> verify on your platform? > >Sure, please feel free to CC me on that patch. Thanks, you are in the cc list of v2. Hope this one works fine on ARM. --=20 Wei Yang Help you, Help me