From: Peter Zijlstra <peterz@infradead.org>
To: Yair Podemsky <ypodemsk@redhat.com>
Cc: mtosatti@redhat.com, ppandit@redhat.com, david@redhat.com,
linux@armlinux.org.uk, mpe@ellerman.id.au, npiggin@gmail.com,
christophe.leroy@csgroup.eu, hca@linux.ibm.com,
gor@linux.ibm.com, agordeev@linux.ibm.com,
borntraeger@linux.ibm.com, svens@linux.ibm.com,
davem@davemloft.net, tglx@linutronix.de, mingo@redhat.com,
bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com,
keescook@chromium.org, paulmck@kernel.org, frederic@kernel.org,
will@kernel.org, ardb@kernel.org, samitolvanen@google.com,
juerg.haefliger@canonical.com, arnd@arndb.de,
rmk+kernel@armlinux.org.uk, geert+renesas@glider.be,
linus.walleij@linaro.org, akpm@linux-foundation.org,
sebastian.reichel@collabora.com, rppt@kernel.org,
aneesh.kumar@linux.ibm.com, x86@kernel.org,
linux-arm-kernel@lists.infradead.org,
linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
sparclinux@vger.kernel.org, linux-arch@vger.kernel.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 0/2] send tlb_remove_table_smp_sync IPI only to necessary CPUs
Date: Wed, 21 Jun 2023 09:43:37 +0200 [thread overview]
Message-ID: <20230621074337.GF2046280@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20230620144618.125703-1-ypodemsk@redhat.com>
On Tue, Jun 20, 2023 at 05:46:16PM +0300, Yair Podemsky wrote:
> Currently the tlb_remove_table_smp_sync IPI is sent to all CPUs
> indiscriminately, this causes unnecessary work and delays notable in
> real-time use-cases and isolated cpus.
> By limiting the IPI to only be sent to cpus referencing the effected
> mm.
> a config to differentiate architectures that support mm_cpumask from
> those that don't will allow safe usage of this feature.
>
> changes from -v1:
> - Previous version included a patch to only send the IPI to CPU's with
> context_tracking in the kernel space, this was removed due to race
> condition concerns.
> - for archs that do not maintain mm_cpumask the mask used should be
> cpu_online_mask (Peter Zijlstra).
>
Would it not be much better to fix the root cause? As per the last time,
there's patches that cure the thp abuse of this.
next prev parent reply other threads:[~2023-06-21 7:44 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-20 14:46 Yair Podemsky
2023-06-20 14:46 ` [PATCH v2 1/2] arch: Introduce ARCH_HAS_CPUMASK_BITS Yair Podemsky
2023-06-20 14:46 ` [PATCH v2 2/2] mm/mmu_gather: send tlb_remove_table_smp_sync IPI only to MM CPUs Yair Podemsky
2023-06-21 17:42 ` Dave Hansen
2023-06-22 13:14 ` ypodemsk
2023-06-22 13:37 ` Dave Hansen
2023-06-26 14:36 ` ypodemsk
2023-06-26 15:23 ` Dave Hansen
2023-06-21 18:02 ` Nadav Amit
2023-06-22 13:57 ` ypodemsk
2023-06-23 3:38 ` Yang Shi
2023-07-03 13:57 ` Peter Zijlstra
2023-06-21 7:43 ` Peter Zijlstra [this message]
2023-06-22 12:47 ` [PATCH v2 0/2] send tlb_remove_table_smp_sync IPI only to necessary CPUs Marcelo Tosatti
2023-07-03 14:09 ` Peter Zijlstra
2023-06-22 13:11 ` ypodemsk
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