From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7EC6CCCFA05 for ; Fri, 7 Nov 2025 15:29:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B50078E0008; Fri, 7 Nov 2025 10:29:02 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B27688E0002; Fri, 7 Nov 2025 10:29:02 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A642B8E0008; Fri, 7 Nov 2025 10:29:02 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 9311F8E0002 for ; Fri, 7 Nov 2025 10:29:02 -0500 (EST) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 20C44C03F6 for ; Fri, 7 Nov 2025 15:29:02 +0000 (UTC) X-FDA: 84084194124.14.6AD8C9F Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf01.hostedemail.com (Postfix) with ESMTP id 32E224000A for ; Fri, 7 Nov 2025 15:28:59 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf01.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1762529340; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=CbzUp7HLI49Fg8paD04i5ybzsDse9dFElebqMJiK6fk=; b=3hFLnIVIkJlqPZTTnFpP7mmChc0uXn3EeMcYQhg3ZB934O/hIbrQA9SYsq+c9JKTtozXMs cUeh7PCK/n4mOVc673L5LBo8cX+qXUGSSfUrIRly+4Qd1VZ/byALdONgU8XKhS0PgNVFv7 1FswLyfqokNukdBbefzYf8uUdpP6JGw= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf01.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1762529340; a=rsa-sha256; cv=none; b=MQb8y24RotdFwiOe+WMegt3coYtnh5TrbySDAZzjLmF4swyZ3PY6a2wElMvvRkjqW2wOJi H1wb3yOa40SNDgeHz0882Sgh4mu+bZ3PLmkIp8IPu2ZDt9oAHjq/DoinP2y4AJ7Q8hWP0o ItWF6rCg1XeODGN0e5gQA7U2GkQQcLw= Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 55F981515; Fri, 7 Nov 2025 07:28:51 -0800 (PST) Received: from [10.57.86.134] (unknown [10.57.86.134]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 7C13D3F694; Fri, 7 Nov 2025 07:28:54 -0800 (PST) Message-ID: <06026ad7-fb85-4a78-ba70-7fa1f5bca0cd@arm.com> Date: Fri, 7 Nov 2025 15:28:53 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 08/12] arm64: mm: replace TIF_LAZY_MMU with in_lazy_mmu_mode() Content-Language: en-GB To: Kevin Brodsky , linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, Alexander Gordeev , Andreas Larsson , Andrew Morton , Boris Ostrovsky , Borislav Petkov , Catalin Marinas , Christophe Leroy , Dave Hansen , David Hildenbrand , "David S. Miller" , David Woodhouse , "H. Peter Anvin" , Ingo Molnar , Jann Horn , Juergen Gross , "Liam R. Howlett" , Lorenzo Stoakes , Madhavan Srinivasan , Michael Ellerman , Michal Hocko , Mike Rapoport , Nicholas Piggin , Peter Zijlstra , Suren Baghdasaryan , Thomas Gleixner , Vlastimil Babka , Will Deacon , Yeoreum Yun , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org References: <20251029100909.3381140-1-kevin.brodsky@arm.com> <20251029100909.3381140-9-kevin.brodsky@arm.com> From: Ryan Roberts In-Reply-To: <20251029100909.3381140-9-kevin.brodsky@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 32E224000A X-Stat-Signature: cns7mnahf3ey4fc7rse8h5u9ptopjfch X-Rspam-User: X-HE-Tag: 1762529339-843112 X-HE-Meta: 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 ELm73eDZ dj/2YFrNWPo42QNZ++JKnJWGJxRJEKG0Sfhxg0e3XTDvs0kgKzteeOyZZHq5rOojz44ZWUH8c3avFQKBUl/0MR04FH67FAfLtJoSnyZOxYCHAKoj0dB9GGxynk4FP7jByXISQEtWoadbxzUGbmq/lZGwE+yQGsX+D4D6zFkw2yJcp7i/YDO+z9Cj5uY3W+nUp+jwVrYsGJTVH2yoJQghrjN4oBu/AiEynDbgsg93eRC5YQtaW1/KnTnabAw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 29/10/2025 10:09, Kevin Brodsky wrote: > The generic lazy_mmu layer now tracks whether a task is in lazy MMU > mode. As a result we no longer need a TIF flag for that purpose - > let's use the new in_lazy_mmu_mode() helper instead. > > Signed-off-by: Kevin Brodsky > --- > arch/arm64/include/asm/pgtable.h | 16 +++------------- > arch/arm64/include/asm/thread_info.h | 3 +-- > 2 files changed, 4 insertions(+), 15 deletions(-) > > diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h > index 535435248923..61ca88f94551 100644 > --- a/arch/arm64/include/asm/pgtable.h > +++ b/arch/arm64/include/asm/pgtable.h > @@ -62,30 +62,21 @@ static inline void emit_pte_barriers(void) > > static inline void queue_pte_barriers(void) > { > - unsigned long flags; > - > if (in_interrupt()) { > emit_pte_barriers(); > return; > } > > - flags = read_thread_flags(); > - > - if (flags & BIT(TIF_LAZY_MMU)) { > - /* Avoid the atomic op if already set. */ > - if (!(flags & BIT(TIF_LAZY_MMU_PENDING))) > - set_thread_flag(TIF_LAZY_MMU_PENDING); > - } else { > + if (in_lazy_mmu_mode()) > + test_and_set_thread_flag(TIF_LAZY_MMU_PENDING); This removes the optimization to only do the atomic set operation if the bit is not already set. I think that should remain. > + else > emit_pte_barriers(); > - } > } > > static inline void arch_enter_lazy_mmu_mode(void) > { > if (in_interrupt()) > return; Why are you keeping this test? Surely it can go? > - > - set_thread_flag(TIF_LAZY_MMU); > } > > static inline void arch_flush_lazy_mmu_mode(void) > @@ -103,7 +94,6 @@ static inline void arch_leave_lazy_mmu_mode(void) > return; > > arch_flush_lazy_mmu_mode(); > - clear_thread_flag(TIF_LAZY_MMU); > } > > #ifdef CONFIG_TRANSPARENT_HUGEPAGE > diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h > index f241b8601ebd..4ff8da0767d9 100644 > --- a/arch/arm64/include/asm/thread_info.h > +++ b/arch/arm64/include/asm/thread_info.h > @@ -84,8 +84,7 @@ void arch_setup_new_exec(void); > #define TIF_SME_VL_INHERIT 28 /* Inherit SME vl_onexec across exec */ > #define TIF_KERNEL_FPSTATE 29 /* Task is in a kernel mode FPSIMD section */ > #define TIF_TSC_SIGSEGV 30 /* SIGSEGV on counter-timer access */ > -#define TIF_LAZY_MMU 31 /* Task in lazy mmu mode */ > -#define TIF_LAZY_MMU_PENDING 32 /* Ops pending for lazy mmu mode exit */ > +#define TIF_LAZY_MMU_PENDING 31 /* Ops pending for lazy mmu mode exit */ > > #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) > #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)