From: Peter Zijlstra <peterz@infradead.org>
To: Rik van Riel <riel@surriel.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
kernel-team@meta.com, dave.hansen@linux.intel.com,
luto@kernel.org, tglx@linutronix.de, mingo@redhat.com,
bp@alien8.de, hpa@zytor.com, akpm@linux-foundation.org,
linux-mm@kvack.org
Subject: Re: [PATCH 01/11] x86/mm: make MMU_GATHER_RCU_TABLE_FREE unconditional
Date: Tue, 24 Dec 2024 19:26:42 +0100 [thread overview]
Message-ID: <20241224182642.GC17252@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <20241223025751.3268975-2-riel@surriel.com>
On Sun, Dec 22, 2024 at 09:55:07PM -0500, Rik van Riel wrote:
> Currently x86 usse CONFIG_MMU_GATHER_TABLE_FREE when using
> paravirt, and not when running on bare metal.
>
> There is no real good reason to do things differently for
> each setup. Make them all the same.
More importantly, the changes you're proposing very much rely on this.
Without TLBi IPIs nothing serializes GUP-fast vs TLBi and this RCU-ish
table free scheme is required.
> Signed-off-by: Rik van Riel <riel@surriel.com>
> Suggested-by: Peter Zijlstra <peterz@infradead.org>
> ---
> arch/x86/Kconfig | 2 +-
> arch/x86/kernel/paravirt.c | 7 +------
> 2 files changed, 2 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 9d7bd0ae48c4..e8743f8c9fd0 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -274,7 +274,7 @@ config X86
> select HAVE_PCI
> select HAVE_PERF_REGS
> select HAVE_PERF_USER_STACK_DUMP
> - select MMU_GATHER_RCU_TABLE_FREE if PARAVIRT
> + select MMU_GATHER_RCU_TABLE_FREE
> select MMU_GATHER_MERGE_VMAS
> select HAVE_POSIX_CPU_TIMERS_TASK_WORK
> select HAVE_REGS_AND_STACK_ACCESS_API
> diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
> index fec381533555..2b78a6b466ed 100644
> --- a/arch/x86/kernel/paravirt.c
> +++ b/arch/x86/kernel/paravirt.c
> @@ -59,11 +59,6 @@ void __init native_pv_lock_init(void)
> static_branch_enable(&virt_spin_lock_key);
> }
>
> -static void native_tlb_remove_table(struct mmu_gather *tlb, void *table)
> -{
> - tlb_remove_page(tlb, table);
> -}
> -
> struct static_key paravirt_steal_enabled;
> struct static_key paravirt_steal_rq_enabled;
>
> @@ -191,7 +186,7 @@ struct paravirt_patch_template pv_ops = {
> .mmu.flush_tlb_kernel = native_flush_tlb_global,
> .mmu.flush_tlb_one_user = native_flush_tlb_one_user,
> .mmu.flush_tlb_multi = native_flush_tlb_multi,
> - .mmu.tlb_remove_table = native_tlb_remove_table,
> + .mmu.tlb_remove_table = tlb_remove_table,
>
> .mmu.exit_mmap = paravirt_nop,
> .mmu.notify_page_enc_status_changed = paravirt_nop,
> --
> 2.47.1
>
next prev parent reply other threads:[~2024-12-24 18:26 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-12-23 2:55 [RFC PATCH v2 00/11] AMD broadcast TLB invalidation Rik van Riel
2024-12-23 2:55 ` [PATCH 01/11] x86/mm: make MMU_GATHER_RCU_TABLE_FREE unconditional Rik van Riel
2024-12-23 6:01 ` Qi Zheng
2024-12-23 20:20 ` Rik van Riel
2024-12-24 18:26 ` Peter Zijlstra [this message]
2024-12-23 2:55 ` [PATCH 02/11] x86/mm: add X86_FEATURE_INVLPGB definition Rik van Riel
2024-12-23 2:55 ` [PATCH 03/11] x86/mm: get INVLPGB count max from CPUID Rik van Riel
2024-12-25 23:42 ` Nadav Amit
2024-12-23 2:55 ` [PATCH 04/11] x86/mm: add INVLPGB support code Rik van Riel
2024-12-23 2:55 ` [PATCH 05/11] x86/mm: use INVLPGB for kernel TLB flushes Rik van Riel
2024-12-23 2:55 ` [PATCH 06/11] x86/tlb: use INVLPGB in flush_tlb_all Rik van Riel
2024-12-23 2:55 ` [PATCH 07/11] x86/mm: use broadcast TLB flushing for page reclaim TLB flushing Rik van Riel
2024-12-23 2:55 ` [PATCH 08/11] x86/mm: enable broadcast TLB invalidation for multi-threaded processes Rik van Riel
2024-12-25 23:22 ` Nadav Amit
2024-12-25 23:32 ` Nadav Amit
2024-12-23 2:55 ` [PATCH 09/11] x86,tlb: do targeted broadcast flushing from tlbbatch code Rik van Riel
2024-12-23 2:55 ` [PATCH 10/11] x86/mm: enable AMD translation cache extensions Rik van Riel
2024-12-23 2:55 ` [PATCH 11/11] x86/mm: only invalidate final translations with INVLPGB Rik van Riel
2024-12-24 18:08 ` [RFC PATCH v2 00/11] AMD broadcast TLB invalidation Michael Kelley
2024-12-25 14:48 ` Rik van Riel
2025-01-10 19:29 ` Tom Lendacky
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