From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ua0-f198.google.com (mail-ua0-f198.google.com [209.85.217.198]) by kanga.kvack.org (Postfix) with ESMTP id D3A936B0069 for ; Thu, 8 Dec 2016 13:42:42 -0500 (EST) Received: by mail-ua0-f198.google.com with SMTP id 20so447613336uak.0 for ; Thu, 08 Dec 2016 10:42:42 -0800 (PST) Received: from mail-ua0-x22e.google.com (mail-ua0-x22e.google.com. [2607:f8b0:400c:c08::22e]) by mx.google.com with ESMTPS id 4si7455291uay.138.2016.12.08.10.42.42 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 08 Dec 2016 10:42:42 -0800 (PST) Received: by mail-ua0-x22e.google.com with SMTP id b35so455737716uaa.3 for ; Thu, 08 Dec 2016 10:42:42 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20161208162150.148763-26-kirill.shutemov@linux.intel.com> References: <20161208162150.148763-1-kirill.shutemov@linux.intel.com> <20161208162150.148763-26-kirill.shutemov@linux.intel.com> From: Andy Lutomirski Date: Thu, 8 Dec 2016 10:42:19 -0800 Message-ID: Subject: Re: [RFC, PATCHv1 24/28] x86/mm: add sync_global_pgds() for configuration with 5-level paging Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: Linus Torvalds , Andrew Morton , X86 ML , Thomas Gleixner , Ingo Molnar , Arnd Bergmann , "H. Peter Anvin" , Andi Kleen , Dave Hansen , linux-arch , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" On Thu, Dec 8, 2016 at 8:21 AM, Kirill A. Shutemov wrote: > This basically restores slightly modified version of original > sync_global_pgds() which we had before foldedl p4d was introduced. > > The only modification is protection against 'address' overflow. > > Signed-off-by: Kirill A. Shutemov > --- > arch/x86/mm/init_64.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 47 insertions(+) > > diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c > index a991f5c4c2c4..d637893ac8c2 100644 > --- a/arch/x86/mm/init_64.c > +++ b/arch/x86/mm/init_64.c > @@ -92,6 +92,52 @@ __setup("noexec32=", nonx32_setup); > * When memory was added/removed make sure all the processes MM have > * suitable PGD entries in the local PGD level page. > */ > +#ifdef CONFIG_X86_5LEVEL > +void sync_global_pgds(unsigned long start, unsigned long end, int removed) > +{ > + unsigned long address; > + > + for (address = start; address <= end && address >= start; > + address += PGDIR_SIZE) { > + const pgd_t *pgd_ref = pgd_offset_k(address); > + struct page *page; > + > + /* > + * When it is called after memory hot remove, pgd_none() > + * returns true. In this case (removed == 1), we must clear > + * the PGD entries in the local PGD level page. > + */ > + if (pgd_none(*pgd_ref) && !removed) > + continue; This isn't quite specific to your patch, but can we assert that, if removed=1, then we're not operating on the vmalloc range? Because if we do, this will be racy is nasty ways. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org