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X-CSE-ConnectionGUID: GS/O5o9RRKWLurReXRz4iQ== X-CSE-MsgGUID: bsLLE0dBSiOcKV5O3oldIQ== X-IronPort-AV: E=McAfee;i="6700,10204,11407"; a="46510210" X-IronPort-AV: E=Sophos;i="6.15,222,1739865600"; d="scan'208";a="46510210" Received: from fmviesa001.fm.intel.com ([10.60.135.141]) by fmvoesa111.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Apr 2025 11:49:20 -0700 X-CSE-ConnectionGUID: KiRWcNbeSv63lS4MoGVjiA== X-CSE-MsgGUID: LFDZ9zPrTIm8z7xl/GMg4w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.15,222,1739865600"; d="scan'208";a="162224203" Received: from mdroper-mobl2.amr.corp.intel.com (HELO [10.124.220.20]) ([10.124.220.20]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Apr 2025 11:49:13 -0700 Message-ID: Date: Fri, 18 Apr 2025 11:49:12 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] x86/mm: Kill a 32-bit #ifdef for shared PMD handling To: "Edgecombe, Rick P" , "linux-kernel@vger.kernel.org" , "dave.hansen@linux.intel.com" Cc: "luto@kernel.org" , "jgross@suse.com" , "x86@kernel.org" , "joro@8bytes.org" , "peterz@infradead.org" , "bp@alien8.de" , "tglx@linutronix.de" , "kirill.shutemov@linux.intel.com" References: <20250418155612.8F276BC7@davehans-spike.ostc.intel.com> <20250418155614.8F925958@davehans-spike.ostc.intel.com> <3a14471baa1fe0803a27922fe9bd929a0062f780.camel@intel.com> From: Dave Hansen Content-Language: en-US Autocrypt: addr=dave.hansen@intel.com; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 4/18/25 11:18, Edgecombe, Rick P wrote: > On Fri, 2025-04-18 at 08:56 -0700, Dave Hansen wrote: >> + >> + if (IS_ENABLED(CONFIG_X86_64)) >> + return; > Nit to throw away if you don't like it, but the below code the conditional is > about special 32 bit requirements, not, not being 64 bit. So I'd have done: > > if (!IS_ENABLED(CONFIG_X86_32)) > return; > > Probably anyone reading this is going to know CONFIG_X86_64 and CONFIG_X86_32 > are exclusive, and there are only two options. But to me the check is a tiny bit > harder to read this way. In either case: I like the suggestion. I think I even wrote it that way originally. I eventually decided to try and optimize for the lucky guy who comes through some day and is removing all the non-64-bit code. It would be easier for them to intuit that the cruft can go away here: if (IS_ENABLED(CONFIG_X86_64)) return; // cruft Does that make sense, or am I optimizing for the wrong thing?