From: Nadav Amit <nadav.amit@gmail.com>
To: Rik van Riel <riel@surriel.com>
Cc: the arch/x86 maintainers <x86@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Borislav Petkov <bp@alien8.de>,
peterz@infradead.org, Dave Hansen <dave.hansen@linux.intel.com>,
zhengqi.arch@bytedance.com, thomas.lendacky@amd.com,
kernel-team@meta.com,
"open list:MEMORY MANAGEMENT" <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
jackmanb@google.com, jannh@google.com, mhklinux@outlook.com,
andrew.cooper3@citrix.com, Manali Shukla <Manali.Shukla@amd.com>
Subject: Re: [PATCH v10 09/12] x86/mm: enable broadcast TLB invalidation for multi-threaded processes
Date: Wed, 12 Feb 2025 14:07:08 +0200 [thread overview]
Message-ID: <940E9420-0CD3-4C9A-AFCC-23433AF8EFA4@gmail.com> (raw)
In-Reply-To: <20250211210823.242681-10-riel@surriel.com>
It all looks pretty sane to me.
One small note:
> On 11 Feb 2025, at 23:08, Rik van Riel <riel@surriel.com> wrote:
>
> +/*
> + * Check whether a process is currently active on more than "threshold" CPUs.
> + * This is a cheap estimation on whether or not it may make sense to assign
> + * a global ASID to this process, and use broadcast TLB invalidation.
> + */
> +static bool mm_active_cpus_exceeds(struct mm_struct *mm, int threshold)
> +{
> + int count = 0;
> + int cpu;
> +
> + /* This quick check should eliminate most single threaded programs. */
> + if (cpumask_weight(mm_cpumask(mm)) <= threshold)
> + return false;
> +
Does it make sense to first check mm.mm_users against the threshold? It might
be less cache-contended.
Anyhow, for what’s it worth:
Reviewed-by: Nadav Amit <nadav.amit@gmail.com <mailto:nadav.amit@gmail.com>>
next prev parent reply other threads:[~2025-02-12 12:08 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-11 21:07 [PATCH v10 00/12] AMD broadcast TLB invalidation Rik van Riel
2025-02-11 21:07 ` [PATCH v10 01/12] x86/mm: make MMU_GATHER_RCU_TABLE_FREE unconditional Rik van Riel
2025-02-11 21:07 ` [PATCH v10 02/12] x86/mm: remove pv_ops.mmu.tlb_remove_table call Rik van Riel
2025-02-11 21:07 ` [PATCH v10 03/12] x86/mm: consolidate full flush threshold decision Rik van Riel
2025-02-11 21:07 ` [PATCH v10 04/12] x86/mm: get INVLPGB count max from CPUID Rik van Riel
2025-02-11 21:08 ` [PATCH v10 05/12] x86/mm: add INVLPGB support code Rik van Riel
2025-02-11 21:08 ` [PATCH v10 06/12] x86/mm: use INVLPGB for kernel TLB flushes Rik van Riel
2025-02-11 21:08 ` [PATCH v10 07/12] x86/mm: use INVLPGB in flush_tlb_all Rik van Riel
2025-02-11 21:08 ` [PATCH v10 08/12] x86/mm: use broadcast TLB flushing for page reclaim TLB flushing Rik van Riel
2025-02-11 21:08 ` [PATCH v10 09/12] x86/mm: enable broadcast TLB invalidation for multi-threaded processes Rik van Riel
2025-02-12 9:54 ` Peter Zijlstra
2025-02-12 10:22 ` Peter Zijlstra
2025-02-12 10:42 ` Peter Zijlstra
2025-02-12 12:07 ` Nadav Amit [this message]
2025-02-12 13:28 ` Brendan Jackman
2025-02-11 21:08 ` [PATCH v10 10/12] x86/mm: do targeted broadcast flushing from tlbbatch code Rik van Riel
2025-02-12 13:32 ` Brendan Jackman
2025-02-11 21:08 ` [PATCH v10 11/12] x86/mm: enable AMD translation cache extensions Rik van Riel
2025-02-11 21:08 ` [PATCH v10 12/12] x86/mm: only invalidate final translations with INVLPGB Rik van Riel
2025-02-12 10:23 ` [PATCH v10 00/12] AMD broadcast TLB invalidation Peter Zijlstra
2025-02-12 10:44 ` Brendan Jackman
2025-02-12 10:59 ` Peter Zijlstra
2025-02-12 15:39 ` Rik van Riel
2025-02-13 13:03 ` Borislav Petkov
2025-02-12 16:30 ` Sean Christopherson
2025-02-12 20:35 ` Michael Kelley
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