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X-IronPort-AV: E=McAfee;i="6600,9927,10992"; a="2794647" X-IronPort-AV: E=Sophos;i="6.06,179,1705392000"; d="scan'208";a="2794647" Received: from fmviesa004.fm.intel.com ([10.60.135.144]) by orvoesa113.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Feb 2024 10:47:06 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.06,179,1705392000"; d="scan'208";a="10168367" Received: from jwbates1-mobl.amr.corp.intel.com (HELO [10.209.48.22]) ([10.209.48.22]) by fmviesa004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Feb 2024 10:47:05 -0800 Message-ID: Date: Thu, 22 Feb 2024 10:47:03 -0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/2] x86/mm: clarify "prev" usage in switch_mm_irqs_off() Content-Language: en-US To: Yosry Ahmed Cc: Ingo Molnar , Thomas Gleixner , Borislav Petkov , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Andrew Morton , x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20240126080644.1714297-1-yosryahmed@google.com> <20240126080644.1714297-2-yosryahmed@google.com> <88cb9996-0e9b-49ec-bc94-f816a5b64870@intel.com> From: Dave Hansen Autocrypt: addr=dave.hansen@intel.com; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Stat-Signature: 3936r8ytpckpsae36mzmwymhra5obf3e X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: ED0EF80012 X-HE-Tag: 1708627626-255434 X-HE-Meta: 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 Ec8IcrVM I4k7OG1rtAHPzY9IgBXNGQ9pqFxrYyVGB3sZxhYGjzTGm5U2ZXlx7SMQPv7bWQLv2rQx56LvVQpsm+mlNanWjHf/mcTigR8w/07662rWzxaHswmWY1QVExUEZqD5KUlPjFPpxk3mcAUecP244/6YIQ3DgGcLNWNLRIwr4t9ogdqvekk37LvTeUyjcB/7NgcBpV34/coIM9yp/zgp5IQ7A9gdiZqtU677lzTvY 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 2/22/24 10:43, Yosry Ahmed wrote: >> /* >> * This optimizes when not actually switching mm's. Some architectures >> * use the 'unused' argument for this optimization, but x86 must use >> * 'cpu_tlbstate.loaded_mm' instead because it does not always keep >> * ->active_mm up to date. >> */ > Yes, this is more clear, thanks! However, Andrew already merged that > patch into mm-stable, so it cannot be amended. I can send a separate > patch to rewrite the comment tho if you'd like, WDYT? > >> Also, I think it might be useful to have the rule that arch/x86 code >> _always_ calls switch_mm_irqs_off() with the first argument (the >> newly-named 'unused') set to NULL. I think there's only one site: > Agreed. I can also send a separate patch for this. Thanks! That would be great. I'd be happy to ack them.