From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>,
Michael Ellerman <mpe@ellerman.id.au>
Cc: Will Deacon <will@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Nick Piggin <npiggin@gmail.com>,
linux-arch@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
Yoshinori Sato <ysato@users.sourceforge.jp>,
Rich Felker <dalias@libc.org>,
"David S. Miller" <davem@davemloft.net>,
Helge Deller <deller@gmx.de>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Paul Burton <paulburton@kernel.org>,
Tony Luck <tony.luck@intel.com>,
Richard Henderson <rth@twiddle.net>,
Nick Hu <nickhu@andestech.com>,
Paul Walmsley <paul.walmsley@sifive.com>
Subject: Re: [PATCH 05/17] asm-generic/tlb: Rename HAVE_RCU_TABLE_NO_INVALIDATE
Date: Mon, 16 Dec 2019 19:24:24 +0530 [thread overview]
Message-ID: <33ed03aa-a34c-3a81-0f83-20c3e8d4eff7@linux.ibm.com> (raw)
In-Reply-To: <a9ae27c8-aa84-cda3-355c-7abb3b450d38@linux.ibm.com>
On 12/16/19 7:10 PM, Aneesh Kumar K.V wrote:
> On 12/16/19 6:50 PM, Peter Zijlstra wrote:
>> On Mon, Dec 16, 2019 at 06:43:53PM +0530, Aneesh Kumar K.V wrote:
>>> On 12/16/19 6:07 PM, Peter Zijlstra wrote:
>>
>>>> I'm confused, are you saing you're happy to have PowerPC eat the extra
>>>> TLB invalidates? I thought you cared about PPC performance :-)
>>>>
>>>>
>>>
>>> Instead can we do
>>>
>>> static inline void tlb_table_invalidate(struct mmu_gather *tlb)
>>> {
>>> #ifndef CONFIG_MMU_GATHER_RCU_TABLE_FREE
>>> * Invalidate page-table caches used by hardware walkers. Then we
>>> still
>>> * need to RCU-sched wait while freeing the pages because software
>>> * walkers can still be in-flight.
>>> */
>>> tlb_flush_mmu_tlbonly(tlb);
>>> #endif
>>> }
>>
>> How does that not break ARM/ARM64/s390 and x86 ?
>>
>
> Hmm I missed that usage of RCU_TABLE_NO_INVALIDATE.
>
> Ok I guess we need to revert this change that went upstream this merge
> window then
>
> commit 52162ec784fa05f3a4b1d8e84421279998be3773
> Author: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
> Date: Thu Oct 24 13:28:00 2019 +0530
>
> powerpc/mm/book3s64/radix: Use freed_tables instead of need_flush_all
>
>
>
> I will review the change closely.
So __p*_free_tlb() routines on ppc64 just mark that we need a page walk
cache flush and the actual flush in done in tlb_flush_mmu. As per
d86564a2f085b79ec046a5cba90188e61235280 (mm/tlb, x86/mm: Support
invalidating TLB caches for RCU_TABLE_FREE ) that is not sufficient?
-aneesh
next prev parent reply other threads:[~2019-12-16 13:54 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-11 12:07 [PATCH 00/17] Fixup page directory freeing Peter Zijlstra
2019-12-11 12:07 ` [PATCH 01/17] sh/tlb: Fix PGTABLE_LEVELS > 2 Peter Zijlstra
2019-12-11 12:07 ` [PATCH 02/17] asm-gemeric/tlb: Remove stray function declarations Peter Zijlstra
2019-12-11 13:19 ` Geert Uytterhoeven
2019-12-11 12:07 ` [PATCH 03/17] asm-generic/tlb: Add missing CONFIG symbol Peter Zijlstra
2019-12-11 12:07 ` [PATCH 04/17] asm-generic/tlb: Rename HAVE_RCU_TABLE_FREE Peter Zijlstra
2019-12-11 12:07 ` [PATCH 05/17] asm-generic/tlb: Rename HAVE_RCU_TABLE_NO_INVALIDATE Peter Zijlstra
2019-12-16 12:31 ` Aneesh Kumar K.V
2019-12-16 12:37 ` Peter Zijlstra
2019-12-16 13:13 ` Aneesh Kumar K.V
2019-12-16 13:20 ` Peter Zijlstra
2019-12-16 13:40 ` Aneesh Kumar K.V
2019-12-16 13:54 ` Aneesh Kumar K.V [this message]
2019-12-16 14:50 ` Peter Zijlstra
2019-12-16 15:14 ` Peter Zijlstra
2019-12-16 15:30 ` Peter Zijlstra
2019-12-16 17:00 ` Aneesh Kumar K.V
2019-12-17 8:51 ` Peter Zijlstra
2019-12-16 14:00 ` Peter Zijlstra
2019-12-11 12:07 ` [PATCH 06/17] asm-generic/tlb: Rename HAVE_MMU_GATHER_PAGE_SIZE Peter Zijlstra
2019-12-11 12:07 ` [PATCH 07/17] asm-generic/tlb: Rename HAVE_MMU_GATHER_NO_GATHER Peter Zijlstra
2019-12-11 12:07 ` [PATCH 08/17] asm-generic/tlb: Provide MMU_GATHER_TABLE_FREE Peter Zijlstra
2019-12-12 9:30 ` Peter Zijlstra
2019-12-12 9:32 ` [PATCH mk-II " Peter Zijlstra
2020-01-26 15:52 ` Guenter Roeck
2020-01-27 8:11 ` Peter Zijlstra
2020-01-27 8:13 ` Aneesh Kumar K.V
2020-01-27 13:05 ` Peter Zijlstra
2020-01-27 13:42 ` Aneesh Kumar K.V
2019-12-11 12:07 ` [PATCH 09/17] sh/tlb: Fix __pmd_free_tlb() Peter Zijlstra
2019-12-11 12:07 ` [PATCH 10/17] sparc32/tlb: Fix __p*_free_tlb() Peter Zijlstra
2019-12-11 12:07 ` [PATCH 11/17] parisc/tlb: " Peter Zijlstra
2019-12-11 12:07 ` [PATCH 12/17] m68k/tlb: " Peter Zijlstra
2019-12-11 12:07 ` [PATCH 13/17] mips/tlb: " Peter Zijlstra
2019-12-11 12:07 ` [PATCH 14/17] ia64/tlb: " Peter Zijlstra
2019-12-11 12:07 ` [PATCH 15/17] alpha/tlb: " Peter Zijlstra
2019-12-11 12:07 ` [PATCH 16/17] nds32/tlb: " Peter Zijlstra
2019-12-11 12:07 ` [PATCH 17/17] riscv/tlb: " Peter Zijlstra
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