From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751597AbdFGQPF (ORCPT ); Wed, 7 Jun 2017 12:15:05 -0400 Received: from ale.deltatee.com ([207.54.116.67]:58404 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750831AbdFGQPE (ORCPT ); Wed, 7 Jun 2017 12:15:04 -0400 To: jglisse@redhat.com, linux-mm@kvack.org References: <1496846780-17393-1-git-send-email-jglisse@redhat.com> Cc: linux-kernel@vger.kernel.org, Andy Lutomirski , Ingo Molnar , "Kirill A . Shutemov" From: Logan Gunthorpe Message-ID: Date: Wed, 7 Jun 2017 10:14:58 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <1496846780-17393-1-git-send-email-jglisse@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 172.16.1.111 X-SA-Exim-Rcpt-To: kirill.shutemov@linux.intel.com, mingo@kernel.org, luto@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, jglisse@redhat.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH] x86/mm/hotplug: fix BUG_ON() after hotremove by not freeing pud v2 X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch still fixes my bug. Tested-by: Logan Gunthorpe Thanks, Logan On 07/06/17 08:46 AM, jglisse@redhat.com wrote: > From: Jérôme Glisse > > With commit af2cf278ef4f we no longer free pud so that we do not > have synchronize all pgd on hotremove/vfree. But the new 5 level > page table patchset reverted that for 4 level page table. > > This patch restore af2cf278ef4f and disable free_pud() if we are > in the 4 level page table case thus avoiding BUG_ON() after hot- > remove. > > af2cf278ef4f x86/mm/hotplug: Don't remove PGD entries in remove_pagetable() > > Changed since v1: > - make free_pud() conditional on the number of page table > level > - improved commit message > > Signed-off-by: Jérôme Glisse > Cc: Andy Lutomirski > Cc: Ingo Molnar > Cc: Kirill A. Shutemov > Cc: Logan Gunthorpe >> thus we now trigger a BUG_ON() l128 in sync_global_pgds() >> >> This patch remove free_pud() like in af2cf278ef4f > --- > arch/x86/mm/init_64.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c > index 95651dc..61028bc 100644 > --- a/arch/x86/mm/init_64.c > +++ b/arch/x86/mm/init_64.c > @@ -771,6 +771,16 @@ static void __meminit free_pmd_table(pmd_t *pmd_start, pud_t *pud) > spin_unlock(&init_mm.page_table_lock); > } > > +/* > + * For 4 levels page table we do not want to free puds but for 5 levels > + * we should free them. This code also need to change to adapt for boot > + * time switching between 4 and 5 level. > + */ > +#if CONFIG_PGTABLE_LEVELS == 4 > +static inline void free_pud_table(pud_t *pud_start, p4d_t *p4d) > +{ > +} > +#else /* CONFIG_PGTABLE_LEVELS == 4 */ > static void __meminit free_pud_table(pud_t *pud_start, p4d_t *p4d) > { > pud_t *pud; > @@ -788,6 +798,7 @@ static void __meminit free_pud_table(pud_t *pud_start, p4d_t *p4d) > p4d_clear(p4d); > spin_unlock(&init_mm.page_table_lock); > } > +#endif /* CONFIG_PGTABLE_LEVELS == 4 */ > > static void __meminit > remove_pte_table(pte_t *pte_start, unsigned long addr, unsigned long end, >