From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f198.google.com (mail-pf1-f198.google.com [209.85.210.198]) by kanga.kvack.org (Postfix) with ESMTP id AA8256B0279 for ; Fri, 12 Oct 2018 13:07:02 -0400 (EDT) Received: by mail-pf1-f198.google.com with SMTP id r81-v6so11963214pfk.11 for ; Fri, 12 Oct 2018 10:07:02 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id u132-v6sor1790227pgb.68.2018.10.12.10.07.01 for (Google Transport Security); Fri, 12 Oct 2018 10:07:01 -0700 (PDT) Date: Fri, 12 Oct 2018 10:06:58 -0700 From: Joel Fernandes Subject: Re: [PATCH v2 2/2] mm: speed up mremap by 500x on large regions Message-ID: <20181012170658.GF223066@joelaf.mtv.corp.google.com> References: <20181012013756.11285-1-joel@joelfernandes.org> <20181012013756.11285-2-joel@joelfernandes.org> <9ed82f9e-88c4-8e4f-8c45-3ef153469603@kot-begemot.co.uk> <20181012143728.t42uvr6etg7gp7fh@kshutemo-mobl1> <4dd52e22-5b51-9b30-7178-fde603a08f88@kot-begemot.co.uk> <97cb3fe1-7bc1-12ff-d602-56c72a5496c5@kot-begemot.co.uk> <20181012165012.GD223066@joelaf.mtv.corp.google.com> <4f969958-913e-cb9f-48fb-e3a88e1d288c@kot-begemot.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4f969958-913e-cb9f-48fb-e3a88e1d288c@kot-begemot.co.uk> Sender: owner-linux-mm@kvack.org List-ID: To: Anton Ivanov Cc: "Kirill A. Shutemov" , linux-kernel@vger.kernel.org, linux-mips@linux-mips.org, Rich Felker , linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Peter Zijlstra , Catalin Marinas , Dave Hansen , Will Deacon , mhocko@kernel.org, linux-mm@kvack.org, lokeshgidra@google.com, linux-riscv@lists.infradead.org, elfring@users.sourceforge.net, Jonas Bonn , linux-s390@vger.kernel.org, dancol@google.com, Yoshinori Sato , sparclinux@vger.kernel.org, linux-xtensa@linux-xtensa.org, linux-hexagon@vger.kernel.org, Helge Deller , "maintainer:X86 ARCHITECTURE 32-BIT AND 64-BIT" , hughd@google.com, "James E.J. Bottomley" , kasan-dev@googlegroups.com, kvmarm@lists.cs.columbia.edu, Ingo Molnar , Geert Uytterhoeven , Andrey Ryabinin , linux-snps-arc@lists.infradead.org, kernel-team@android.com, Sam Creasey , Fenghua Yu , Jeff Dike , linux-um@lists.infradead.org, Stefan Kristiansson , Julia Lawall , linux-m68k@lists.linux-m68k.org, openrisc@lists.librecores.org, Borislav Petkov , Andy Lutomirski , nios2-dev@lists.rocketboards.org, Stafford Horne , Guan Xuetao , linux-arm-kernel@lists.infradead.org, Chris Zankel , Tony Luck , Richard Weinberger , linux-parisc@vger.kernel.org, pantin@google.com, Max Filippov , minchan@kernel.org, Thomas Gleixner , linux-alpha@vger.kernel.org, Ley Foon Tan , akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org, "David S. Miller" On Fri, Oct 12, 2018 at 05:58:40PM +0100, Anton Ivanov wrote: [...] > > > > > > If I read the code right, MIPS completely ignores the address > > > > > > argument so > > > > > > set_pmd_at there may not have the effect which this patch is trying to > > > > > > achieve. > > > > > Ignoring address is fine. Most architectures do that.. > > > > > The ideas is to move page table to the new pmd slot. It's nothing to do > > > > > with the address passed to set_pmd_at(). > > > > If that is it's only function, then I am going to appropriate the code > > > > out of the MIPS tree for further uml testing. It does exactly that - > > > > just move the pmd the new slot. > > > > > > > > A. > > > > > > A. > > > > > > From ac265d96897a346b05646fce91784ed4922c7f8d Mon Sep 17 00:00:00 2001 > > > From: Anton Ivanov > > > Date: Fri, 12 Oct 2018 17:24:10 +0100 > > > Subject: [PATCH] Incremental fixes to the mmremap patch > > > > > > Signed-off-by: Anton Ivanov > > > --- > > > arch/um/include/asm/pgalloc.h | 4 ++-- > > > arch/um/include/asm/pgtable.h | 3 +++ > > > arch/um/kernel/tlb.c | 6 ++++++ > > > 3 files changed, 11 insertions(+), 2 deletions(-) > > > > > > diff --git a/arch/um/include/asm/pgalloc.h b/arch/um/include/asm/pgalloc.h > > > index bf90b2aa2002..99eb5682792a 100644 > > > --- a/arch/um/include/asm/pgalloc.h > > > +++ b/arch/um/include/asm/pgalloc.h > > > @@ -25,8 +25,8 @@ > > > extern pgd_t *pgd_alloc(struct mm_struct *); > > > extern void pgd_free(struct mm_struct *mm, pgd_t *pgd); > > > -extern pte_t *pte_alloc_one_kernel(struct mm_struct *, unsigned long); > > > -extern pgtable_t pte_alloc_one(struct mm_struct *, unsigned long); > > > +extern pte_t *pte_alloc_one_kernel(struct mm_struct *); > > > +extern pgtable_t pte_alloc_one(struct mm_struct *); > > If its Ok, let me handle this bit since otherwise it complicates things for > > me. > > > > > static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte) > > > { > > > diff --git a/arch/um/include/asm/pgtable.h b/arch/um/include/asm/pgtable.h > > > index 7485398d0737..1692da55e63a 100644 > > > --- a/arch/um/include/asm/pgtable.h > > > +++ b/arch/um/include/asm/pgtable.h > > > @@ -359,4 +359,7 @@ do { \ > > > __flush_tlb_one((vaddr)); \ > > > } while (0) > > > +extern void set_pmd_at(struct mm_struct *mm, unsigned long addr, > > > + pmd_t *pmdp, pmd_t pmd); > > > + > > > #endif > > > diff --git a/arch/um/kernel/tlb.c b/arch/um/kernel/tlb.c > > > index 763d35bdda01..d17b74184ba0 100644 > > > --- a/arch/um/kernel/tlb.c > > > +++ b/arch/um/kernel/tlb.c > > > @@ -647,3 +647,9 @@ void force_flush_all(void) > > > vma = vma->vm_next; > > > } > > > } > > > +void set_pmd_at(struct mm_struct *mm, unsigned long addr, > > > + pmd_t *pmdp, pmd_t pmd) > > > +{ > > > + *pmdp = pmd; > > > +} > > > + > > I believe this should be included in a separate patch since it is not related > > specifically to pte_alloc argument removal. If you want, I could split it > > into a separate patch for my series with you as author. > > > Whichever is more convenient for you. Ok. > One thing to note - tlb flush is extremely expensive on uml. > > I have lifted the definition of set_pmd_at from the mips tree and removed > the tlb_flush_all from it for this exact reason. > > If I read the original patch correctly, it does its own flush control so > set_pmd_at does not need to do a force flush every time. It is done further > up the chain. That is correct. It is not done during the optimization, but is done later after the pmds have moved. thanks, - Joel