From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Osipenko Subject: Re: [PATCH 3/5] mm/mremap: use pmd_addr_end to calculate next in move_page_tables() Date: Tue, 28 Jan 2020 18:59:48 +0300 Message-ID: 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> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20200128004301.GD20624@richard> Content-Language: en-US Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Wei Yang , Russell King - ARM Linux Cc: akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, aneesh.kumar-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org, kirill-oKw7cIdHH8eLwutG50LtGA@public.gmane.org, yang.shi-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org, thellstrom-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org, Thierry Reding , Jon Hunter , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" List-Id: linux-tegra@vger.kernel.org 28.01.2020 03:43, Wei Yang пишет: > On Sun, Jan 26, 2020 at 05:47:57PM +0300, Dmitry Osipenko wrote: >> 18.01.2020 02:22, Wei Yang пишет: >>> 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, >>> >>> for (; old_addr < old_end; old_addr += extent, new_addr += extent) { >>> cond_resched(); >>> - next = (old_addr + PMD_SIZE) & PMD_MASK; >>> - /* even if next overflowed, extent below will be ok */ >>> + next = pmd_addr_end(old_addr, old_end); >>> extent = next - old_addr; >>> - if (extent > old_end - old_addr) >>> - extent = old_end - old_addr; >>> old_pmd = 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, >>> >>> if (pte_alloc(new_vma->vm_mm, new_pmd)) >>> break; >>> - next = (new_addr + PMD_SIZE) & PMD_MASK; >>> + next = pmd_addr_end(new_addr, new_addr + len); >>> if (extent > next - new_addr) >>> extent = 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 NVIDIA >> 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 explanation. Please take a look at this: [1] https://elixir.bootlin.com/linux/v5.5/source/arch/arm/include/asm/pgtable-2level.h#L210 [2] https://elixir.bootlin.com/linux/v5.5/source/include/asm-generic/pgtable.h#L549 [3] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c0ba10b512eb2e2a3888b6e6cc0e089f5e7a191b