From: bsingharora@gmail.com (Balbir Singh) To: linux-riscv@lists.infradead.org Subject: [PATCH 2/4] mm: speed up mremap by 500x on large regions (v2) Date: Wed, 24 Oct 2018 22:57:33 +1100 [thread overview] Message-ID: <20181024115733.GN8537@350D> (raw) In-Reply-To: <20181024101255.it4lptrjogalxbey@kshutemo-mobl1> On Wed, Oct 24, 2018 at 01:12:56PM +0300, Kirill A. Shutemov wrote: > On Fri, Oct 12, 2018 at 06:31:58PM -0700, Joel Fernandes (Google) wrote: > > diff --git a/mm/mremap.c b/mm/mremap.c > > index 9e68a02a52b1..2fd163cff406 100644 > > --- a/mm/mremap.c > > +++ b/mm/mremap.c > > @@ -191,6 +191,54 @@ static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd, > > drop_rmap_locks(vma); > > } > > > > +static bool move_normal_pmd(struct vm_area_struct *vma, unsigned long old_addr, > > + unsigned long new_addr, unsigned long old_end, > > + pmd_t *old_pmd, pmd_t *new_pmd, bool *need_flush) > > +{ > > + spinlock_t *old_ptl, *new_ptl; > > + struct mm_struct *mm = vma->vm_mm; > > + > > + if ((old_addr & ~PMD_MASK) || (new_addr & ~PMD_MASK) > > + || old_end - old_addr < PMD_SIZE) > > + return false; > > + > > + /* > > + * The destination pmd shouldn't be established, free_pgtables() > > + * should have release it. > > + */ > > + if (WARN_ON(!pmd_none(*new_pmd))) > > + return false; > > + > > + /* > > + * We don't have to worry about the ordering of src and dst > > + * ptlocks because exclusive mmap_sem prevents deadlock. > > + */ > > + old_ptl = pmd_lock(vma->vm_mm, old_pmd); > > + if (old_ptl) { > > How can it ever be false? > > > + pmd_t pmd; > > + > > + new_ptl = pmd_lockptr(mm, new_pmd); Looks like this is largely inspired by move_huge_pmd(), I guess a lot of the code applies, why not just reuse as much as possible? The same comments w.r.t mmap_sem helping protect against lock order issues applies as well. > > + if (new_ptl != old_ptl) > > + spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); > > + > > + /* Clear the pmd */ > > + pmd = *old_pmd; > > + pmd_clear(old_pmd); > > + > > + VM_BUG_ON(!pmd_none(*new_pmd)); > > + > > + /* Set the new pmd */ > > + set_pmd_at(mm, new_addr, new_pmd, pmd); > > + if (new_ptl != old_ptl) > > + spin_unlock(new_ptl); > > + spin_unlock(old_ptl); > > + > > + *need_flush = true; > > + return true; > > + } > > + return false; > > +} > > + > -- > Kirill A. Shutemov >
WARNING: multiple messages have this Message-ID (diff)
From: Balbir Singh <bsingharora@gmail.com> To: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: linux-mips@linux-mips.org, Rich Felker <dalias@libc.org>, linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>, Catalin Marinas <catalin.marinas@arm.com>, Dave Hansen <dave.hansen@linux.intel.com>, Will Deacon <will.deacon@arm.com>, mhocko@kernel.org, linux-mm@kvack.org, lokeshgidra@google.com, "Joel Fernandes \(Google\)" <joel@joelfernandes.org>, linux-riscv@lists.infradead.org, elfring@users.sourceforge.net, Jonas Bonn <jonas@southpole.se>, kvmarm@lists.cs.columbia.edu, dancol@google.com, Yoshinori Sato <ysato@users.sourceforge.jp>, sparclinux@vger.kernel.org, linux-xtensa@linux-xtensa.org, linux-hexagon@vger.kernel.org, Helge Deller <deller@gmx.de>, "maintainer:X86 ARCHITECTURE \(32-BIT AND 64-BIT\)" <x86@kernel.org>, hughd@google.com, "James E.J. Bottomley" <jejb@parisc-linux.org>, kasan-dev@googlegroups.com, anton.ivanov@kot-begemot.co.uk, Ingo Molnar <mingo@redhat.com>, Geert Uytterhoeven <geert@linux-m68k.org>, Andrey Ryabinin <aryabinin@virtuozzo.com>, linux-snps-arc@lists.infradead.org, kernel-team@android.com, Sam Creasey <sammy@sammy.net>, Fenghua Yu <fenghua.yu@intel.com>, linux-s390@vger.kernel.org, Jeff Dike <jdike@addtoit.com>, linux-um@lists.infradead.org, Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>, Julia Lawall <Julia.Lawall@lip6.fr>, linux-m68k@lists.linux-m68k.org, Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>, nios2-dev@lists.rocketboards.org, Stafford Horne <shorne@gmail.com>, Guan Xuetao <gxt@pku.edu.cn>, Chris Zankel <chris@zankel.net>, Tony Luck <tony.luck@intel.com>, Richard Weinberger <richard@nod.at>, linux-parisc@vger.kernel.org, pantin@google.com, Max Filippov <jcmvbkbc@gmail.com>, linux-kernel@vger.kernel.org, minchan@kernel.org, Thomas Gleixner <tglx@linutronix.de>, linux-alpha@vger.kernel.org, Ley Foon Tan <lftan@altera.com>, akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org, "David S. Miller" <davem@davemloft.net> Subject: Re: [PATCH 2/4] mm: speed up mremap by 500x on large regions (v2) Date: Wed, 24 Oct 2018 22:57:33 +1100 [thread overview] Message-ID: <20181024115733.GN8537@350D> (raw) Message-ID: <20181024115733.mZpxzNRdRAIDc4z8RZlmwTLR_6XbnZ8uf8EzntNJZas@z> (raw) In-Reply-To: <20181024101255.it4lptrjogalxbey@kshutemo-mobl1> On Wed, Oct 24, 2018 at 01:12:56PM +0300, Kirill A. Shutemov wrote: > On Fri, Oct 12, 2018 at 06:31:58PM -0700, Joel Fernandes (Google) wrote: > > diff --git a/mm/mremap.c b/mm/mremap.c > > index 9e68a02a52b1..2fd163cff406 100644 > > --- a/mm/mremap.c > > +++ b/mm/mremap.c > > @@ -191,6 +191,54 @@ static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd, > > drop_rmap_locks(vma); > > } > > > > +static bool move_normal_pmd(struct vm_area_struct *vma, unsigned long old_addr, > > + unsigned long new_addr, unsigned long old_end, > > + pmd_t *old_pmd, pmd_t *new_pmd, bool *need_flush) > > +{ > > + spinlock_t *old_ptl, *new_ptl; > > + struct mm_struct *mm = vma->vm_mm; > > + > > + if ((old_addr & ~PMD_MASK) || (new_addr & ~PMD_MASK) > > + || old_end - old_addr < PMD_SIZE) > > + return false; > > + > > + /* > > + * The destination pmd shouldn't be established, free_pgtables() > > + * should have release it. > > + */ > > + if (WARN_ON(!pmd_none(*new_pmd))) > > + return false; > > + > > + /* > > + * We don't have to worry about the ordering of src and dst > > + * ptlocks because exclusive mmap_sem prevents deadlock. > > + */ > > + old_ptl = pmd_lock(vma->vm_mm, old_pmd); > > + if (old_ptl) { > > How can it ever be false? > > > + pmd_t pmd; > > + > > + new_ptl = pmd_lockptr(mm, new_pmd); Looks like this is largely inspired by move_huge_pmd(), I guess a lot of the code applies, why not just reuse as much as possible? The same comments w.r.t mmap_sem helping protect against lock order issues applies as well. > > + if (new_ptl != old_ptl) > > + spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); > > + > > + /* Clear the pmd */ > > + pmd = *old_pmd; > > + pmd_clear(old_pmd); > > + > > + VM_BUG_ON(!pmd_none(*new_pmd)); > > + > > + /* Set the new pmd */ > > + set_pmd_at(mm, new_addr, new_pmd, pmd); > > + if (new_ptl != old_ptl) > > + spin_unlock(new_ptl); > > + spin_unlock(old_ptl); > > + > > + *need_flush = true; > > + return true; > > + } > > + return false; > > +} > > + > -- > Kirill A. Shutemov > _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv
next prev parent reply other threads:[~2018-10-24 11:57 UTC|newest] Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-10-13 1:31 [PATCH 0/4] Add support for fast mremap Joel Fernandes (Google) 2018-10-13 1:31 ` Joel Fernandes (Google) 2018-10-13 1:31 ` [PATCH 1/4] treewide: remove unused address argument from pte_alloc functions (v2) Joel Fernandes (Google) 2018-10-13 1:31 ` Joel Fernandes (Google) 2018-10-24 8:37 ` Peter Zijlstra 2018-10-24 8:37 ` Peter Zijlstra 2018-10-25 2:21 ` Joel Fernandes 2018-10-25 2:21 ` Joel Fernandes 2018-10-26 8:52 ` Peter Zijlstra 2018-10-26 8:52 ` Peter Zijlstra 2018-10-25 10:47 ` Kirill A. Shutemov 2018-10-25 10:47 ` Kirill A. Shutemov 2018-10-26 8:50 ` Peter Zijlstra 2018-10-26 8:50 ` Peter Zijlstra 2018-10-13 1:31 ` [PATCH 2/4] mm: speed up mremap by 500x on large regions (v2) Joel Fernandes (Google) 2018-10-13 1:31 ` Joel Fernandes (Google) 2018-10-15 9:42 ` Christoph Hellwig 2018-10-15 9:42 ` Christoph Hellwig 2018-10-15 22:33 ` Joel Fernandes 2018-10-15 22:33 ` Joel Fernandes 2018-10-16 11:29 ` Vlastimil Babka 2018-10-16 11:29 ` Vlastimil Babka 2018-10-16 19:43 ` Joel Fernandes 2018-10-16 19:43 ` Joel Fernandes 2018-10-17 7:38 ` Vlastimil Babka 2018-10-17 7:38 ` Vlastimil Babka 2018-10-24 10:12 ` Kirill A. Shutemov 2018-10-24 10:12 ` Kirill A. Shutemov 2018-10-24 11:57 ` Balbir Singh [this message] 2018-10-24 11:57 ` Balbir Singh 2018-10-24 12:57 ` Kirill A. Shutemov 2018-10-24 12:57 ` Kirill A. Shutemov 2018-10-25 2:09 ` Joel Fernandes 2018-10-25 2:09 ` Joel Fernandes 2018-10-25 10:19 ` Kirill A. Shutemov 2018-10-25 10:19 ` Kirill A. Shutemov 2018-10-26 21:11 ` Joel Fernandes 2018-10-26 21:11 ` Joel Fernandes 2018-10-29 10:28 ` Will Deacon 2018-10-29 10:28 ` Will Deacon 2018-10-25 2:13 ` Joel Fernandes 2018-10-25 2:13 ` Joel Fernandes 2018-10-27 10:21 ` Balbir Singh 2018-10-27 10:21 ` Balbir Singh 2018-10-27 19:39 ` Joel Fernandes 2018-10-27 19:39 ` Joel Fernandes 2018-10-28 22:40 ` Balbir Singh 2018-10-28 22:40 ` Balbir Singh 2018-10-13 1:31 ` [PATCH 3/4] arm64: select HAVE_MOVE_PMD for faster mremap (v1) Joel Fernandes (Google) 2018-10-13 1:31 ` Joel Fernandes (Google) 2018-10-13 1:32 ` [PATCH 4/4] x86: " Joel Fernandes (Google) 2018-10-13 1:32 ` Joel Fernandes (Google)
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