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 A8168CA1013 for ; Mon, 8 Sep 2025 07:32:44 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id F0DFE8E0009; Mon, 8 Sep 2025 03:32:43 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id EBEC28E0001; Mon, 8 Sep 2025 03:32:43 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DADEF8E0009; Mon, 8 Sep 2025 03:32:43 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id CA1E38E0001 for ; Mon, 8 Sep 2025 03:32:43 -0400 (EDT) Received: from smtpin29.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 6C44D11B19D for ; Mon, 8 Sep 2025 07:32:43 +0000 (UTC) X-FDA: 83865265806.29.33CDC8F Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf20.hostedemail.com (Postfix) with ESMTP id B5A031C0005 for ; Mon, 8 Sep 2025 07:32:41 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf20.hostedemail.com: domain of kevin.brodsky@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=kevin.brodsky@arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1757316761; 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=5MXJVs4sRjIzs/FqbYFU50YGWM5NgmUAUp6zmg3Kby4=; b=ph+q/+EgsCsB5pKDU56d452Y9xI5PC3dnTHfV+T5sWSpKcj4l5CbZVV8pUysucpVWOMioO cYRV7WP+5Zl2PtCRYoGDJFuyHkW3BaFIzWsfMrBRM7zoYT7rUOqFjvY/F3VEshPGuyWpNl nREJrHrRAnBlB+Od2yZfUGFKATYyMqc= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf20.hostedemail.com: domain of kevin.brodsky@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=kevin.brodsky@arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1757316761; a=rsa-sha256; cv=none; b=CJ6q/HpOyFIY6W197TKOPxBXJFi9xMDnDbLuCphIgUitJbpxZpfMpP0AylSjPI0nor7oGP K5fql3MEw02kpEx/afzPCrb+FA0ReWo5RDDwo/IDOVmkGTGPsWi5BI2j1d6cvFwkSdEeXQ cBjuCR/O+vZHE10B5haSTzw9QMWEuEM= 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 88AA2169C; Mon, 8 Sep 2025 00:32:32 -0700 (PDT) Received: from [10.57.58.69] (unknown [10.57.58.69]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id CFA563F63F; Mon, 8 Sep 2025 00:32:34 -0700 (PDT) Message-ID: <1f822d8b-eb46-4998-b1c1-9996d70e1958@arm.com> Date: Mon, 8 Sep 2025 09:32:32 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 5/7] powerpc/mm: support nested lazy_mmu sections To: Alexander Gordeev Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andreas Larsson , Andrew Morton , Boris Ostrovsky , Borislav Petkov , Catalin Marinas , Christophe Leroy , Dave Hansen , David Hildenbrand , "David S. Miller" , "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 , Ryan Roberts , Suren Baghdasaryan , Thomas Gleixner , Vlastimil Babka , Will Deacon , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org References: <20250904125736.3918646-1-kevin.brodsky@arm.com> <20250904125736.3918646-6-kevin.brodsky@arm.com> <074ff6ab-5868-4fde-b5bb-9e17632ad817-agordeev@linux.ibm.com> Content-Language: en-GB From: Kevin Brodsky In-Reply-To: <074ff6ab-5868-4fde-b5bb-9e17632ad817-agordeev@linux.ibm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: zemgoo4fe3qcyu49mp4qjwj7sntpxj16 X-Rspam-User: X-Rspamd-Queue-Id: B5A031C0005 X-Rspamd-Server: rspam05 X-HE-Tag: 1757316761-66410 X-HE-Meta: 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 KbR5DiwE zyxKo1CS6nbVPCsJEieaEC6RcVUVxMxpRE2F75MXAUd0bgJQsmr/km0Ks21vcVGhcq+qfR0MabDHmtBcZPsshDE9bcM8Me2A2kiGedQm3FI+USMhFqxlVfyydM67wSvyatFbIRW3SwjzxRkSZPQ8H9rO/j2Mk981SCXRMX0EGbz/pivi73390lEe6dTrV+1YMTBNY 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 05/09/2025 17:52, Alexander Gordeev wrote: > On Thu, Sep 04, 2025 at 01:57:34PM +0100, Kevin Brodsky wrote: > ... >> static inline lazy_mmu_state_t arch_enter_lazy_mmu_mode(void) >> { >> struct ppc64_tlb_batch *batch; >> + int lazy_mmu_nested; >> >> if (radix_enabled()) >> return LAZY_MMU_DEFAULT; >> @@ -39,9 +40,14 @@ static inline lazy_mmu_state_t arch_enter_lazy_mmu_mode(void) >> */ >> preempt_disable(); >> batch = this_cpu_ptr(&ppc64_tlb_batch); >> - batch->active = 1; >> + lazy_mmu_nested = batch->active; >> >> - return LAZY_MMU_DEFAULT; >> + if (!lazy_mmu_nested) { > Why not just? > > if (!batch->active) { Very fair question! I think the extra variable made sense in an earlier version of that patch, but now it's used only once and doesn't really improve readability either. Will remove it in v2, also in patch 6 (basically the same code). Thanks! - Kevin