From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:37994 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726237AbfEEGUO (ORCPT ); Sun, 5 May 2019 02:20:14 -0400 Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x4566YOw093026 for ; Sun, 5 May 2019 02:20:13 -0400 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0a-001b2d01.pphosted.com with ESMTP id 2s9r1bvafn-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Sun, 05 May 2019 02:20:12 -0400 Received: from localhost by e06smtp01.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Sun, 5 May 2019 07:20:10 +0100 Date: Sun, 5 May 2019 09:19:57 +0300 From: Mike Rapoport Subject: Re: [PATCH 04/15] arm64: switch to generic version of pte allocation References: <1556810922-20248-1-git-send-email-rppt@linux.ibm.com> <1556810922-20248-5-git-send-email-rppt@linux.ibm.com> <20190503100508.GB47811@lakrids.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190503100508.GB47811@lakrids.cambridge.arm.com> Message-ID: <20190505061956.GE15755@rapoport-lnx> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Mark Rutland Cc: Andrew Morton , Arnd Bergmann , Catalin Marinas , Geert Uytterhoeven , Greentime Hu , Guan Xuetao , Guo Ren , Helge Deller , Ley Foon Tan , Matthew Wilcox , Matt Turner , Michael Ellerman , Michal Hocko , Palmer Dabbelt , Paul Burton , Richard Kuo , Richard Weinberger , Russell King , Sam Creasey , x86@kernel.org, linux-alpha@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-hexagon@vger.kernel.org, linux-kernel@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-um@lists.infradead.org, nios2-dev@lists.rocketboards.org Message-ID: <20190505061957.hFMXPEXhKvzLLuGL4JAqNbrGYSEL6mM6Xf1KtICnJbM@z> On Fri, May 03, 2019 at 11:05:09AM +0100, Mark Rutland wrote: > Hi, > > On Thu, May 02, 2019 at 06:28:31PM +0300, Mike Rapoport wrote: > > The PTE allocations in arm64 are identical to the generic ones modulo the > > GFP flags. > > > > Using the generic pte_alloc_one() functions ensures that the user page > > tables are allocated with __GFP_ACCOUNT set. > > > > The arm64 definition of PGALLOC_GFP is removed and replaced with > > GFP_PGTABLE_USER for p[gum]d_alloc_one() and for KVM memory cache. > > > > The mappings created with create_pgd_mapping() are now using > > GFP_PGTABLE_KERNEL. > > > > The conversion to the generic version of pte_free_kernel() removes the NULL > > check for pte. > > > > The pte_free() version on arm64 is identical to the generic one and > > can be simply dropped. > > > > Signed-off-by: Mike Rapoport > > --- > > arch/arm64/include/asm/pgalloc.h | 43 ++++------------------------------------ > > arch/arm64/mm/mmu.c | 2 +- > > arch/arm64/mm/pgd.c | 4 ++-- > > virt/kvm/arm/mmu.c | 2 +- > > 4 files changed, 8 insertions(+), 43 deletions(-) > > [...] > > > diff --git a/arch/arm64/mm/pgd.c b/arch/arm64/mm/pgd.c > > index 289f911..2ef1a53 100644 > > --- a/arch/arm64/mm/pgd.c > > +++ b/arch/arm64/mm/pgd.c > > @@ -31,9 +31,9 @@ static struct kmem_cache *pgd_cache __ro_after_init; > > pgd_t *pgd_alloc(struct mm_struct *mm) > > { > > if (PGD_SIZE == PAGE_SIZE) > > - return (pgd_t *)__get_free_page(PGALLOC_GFP); > > + return (pgd_t *)__get_free_page(GFP_PGTABLE_USER); > > else > > - return kmem_cache_alloc(pgd_cache, PGALLOC_GFP); > > + return kmem_cache_alloc(pgd_cache, GFP_PGTABLE_USER); > > } > > In efi_virtmap_init() we use pgd_alloc() to allocate a pgd for EFI > runtime services, which we map with a special kernel page table. > > I'm not sure if accounting that is problematic, as it's allocated in a > kernel thread off the back of an early_initcall. The accounting bypasses kernel threads so there should be no problem. > Just to check, Is that sound, or do we need a pgd_alloc_kernel()? > > Thanks, > Mark. > -- Sincerely yours, Mike.