From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f53.google.com (mail-wm1-f53.google.com [209.85.128.53]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 366082DF6F4 for ; Fri, 21 Nov 2025 11:59:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.53 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763726376; cv=none; b=M4sZaub93IMvu6+a7nk96WDkqfcxeEUIhF/0JHgz+bq6cRcegKyyJOCwmnKx9PGI4XA+sY8aoCQipOj+xAnOymRdjWD3w64DBxfBLbeAZ/iSoHsN7eTpoM4Qt2JtuuX4UYur8aq5A/Rp5QXs8fUo/gZv7Z6TgO2E+XPLDWN/nbs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763726376; c=relaxed/simple; bh=Tge1dpOQNIViRaRkvFrR0hadWsD35vB90mc9bl7lemg=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=GaXP3lez17XIaC5WvIQCtBdjOnGgj8INqpbudG/krlw2YX5oiYR1R6eJCjjg6u6ejQXztt/xQLXTVqCKY+pAts3AWOVOM3kk9Y1bGwsk4lDhCEOoPRl2w2C75G9vGCRwPnkDb26NQE42qc5qVzPuI81oFMyG8B7WP5/BvQw6j8o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=OVAlzrvq; arc=none smtp.client-ip=209.85.128.53 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="OVAlzrvq" Received: by mail-wm1-f53.google.com with SMTP id 5b1f17b1804b1-477b198f4bcso14018475e9.3 for ; Fri, 21 Nov 2025 03:59:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1763726373; x=1764331173; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=DdAEfCRG7LYbXV3n1fnF3mp3pmfGB4hFtYRv7a4CSFU=; b=OVAlzrvqcfAfdND/td2zGFPMqGYO+FoHf4FjoC8ztFVemfkHrHjOErIDz0CThDcayP 0mNS4kYpgwoFJOgGCVpjebWUqk2oc1rUvV0hczRtmd/+KHZrErf0ZYs4H4gFtfW9uISE 2WK4tBBhIDAgJTKex95z7FnP2Uo0BO+qen2sMPx4+D4DkEv+tDNZvuo+oV41rhyDLzXy Q6Db/WPJ5i2AcnQrG9l3tRBKEilOztKnS0vme/0AW/tmD1/pKEOvIH05VMHD67OQPXp8 aEGghWuh0FrTdmDf4EGGKwDz/z+TMywy8AQEcsLUosMdn4CigMkzFLsORu2CpxR9Luvu UZNw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1763726373; x=1764331173; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=DdAEfCRG7LYbXV3n1fnF3mp3pmfGB4hFtYRv7a4CSFU=; b=esfEiPdp/dAIY12+eaDERKPHUtVCEQc9gxB89mVrgV17Xta+SH4mXFXc4t2woeOlqg Cvg8YvxvW3YgcLfuKGGOtckmsOmNmXWVZBZtgqdSLqrXtovuSE/eu4WGklQojji5xbYp 9PD8hAeP/XaUHAlTkP9vlc732u0c3NTH/9mKBn9U3DR0TbkyXWhJeRm2tYYUw+aZgQKw cc0tqJvlbpZ84Qp01XY3Ovdb67Ea2zgx+JhVFwUVVoLMMax/CNHeiUtM9FeMSCN4mwqT 7OTZIrbyD2lufhpU9NDAVPEJEYcta6p1P0Ta+32TCiVM15cfW67Z9PKWqU65KX7cCNX3 pxZQ== X-Forwarded-Encrypted: i=1; AJvYcCX9reQLtOfTtclIV8cLoisyu6A8pYqL5K1kEp2/TXsF15aCsOmdE49BTzRgbkO8tMxi8/FwVUqYnaEf@vger.kernel.org X-Gm-Message-State: AOJu0YzZIBKJrTXue1c6XqaV/uI7zDFbwrVy4EgwAnGpb6lZrF0HNODf pNpF+n9+tMx+xdpkrMl4dKFMle8bYDMa1F0HBkHAvUK3CUneK6Bj4s0h X-Gm-Gg: ASbGnct1Y/0FeV377/di3hLQoGNYYR1S7oQ7+rGSYCmPB0TtGB9DTxYf5mQ+GzangVp KUjNdHKaJKcEWwuKQLSra7l9g/LrvSnCgtWgcFKbDukA5i6ssR8+YGHHs+dM2DwgNSA3zHwwlUt z9UHxBo8ybmJRBOlWO1Y3/ebls3BBx0DaAZphHqjZIc+Z5cbPjVjolG7V3RFYBp0d/2OY+705FW 9XpfN73zmszFbrNeRBDEC5MWJYOFr2aurx6r8ZFkbrxR4H0SNMTG4pE7CnifOBzJTwz6RjTyyOC uK4Dyl3MHPGTA6MKA3nso5oW9nPqfSkqyNsfS/3NuTE1L4+pf1H4Qa75FBQnabqO537WU5QeaH9 Sm6Q0atf/CxZjr38IzoIz1g0t/+ElFasrT/a+jBkzzHySdteiBS8aMF++AtNwDKK+k3w8B090l8 K8neqwkS8rcamvcxqYAKELdZ36IhdAl+0Mz3EVriLQi34OelhOhgRW X-Google-Smtp-Source: AGHT+IEXB0RB62gXSzOzEV+4sONTX8HwsLR9F+MH0BZ/CexDYl5S87COeJ8BmSIVYwhp+H/hd0GvZA== X-Received: by 2002:a05:600c:1f8f:b0:477:3e0b:c0e3 with SMTP id 5b1f17b1804b1-477c01eba39mr18354365e9.32.1763726373122; Fri, 21 Nov 2025 03:59:33 -0800 (PST) Received: from pumpkin (82-69-66-36.dsl.in-addr.zen.co.uk. [82.69.66.36]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-477bf3b4c13sm39025065e9.13.2025.11.21.03.59.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 21 Nov 2025 03:59:32 -0800 (PST) Date: Fri, 21 Nov 2025 11:59:31 +0000 From: David Laight To: Andreas Schwab Cc: "Theodore Tso" , Guan-Chun Wu <409411716@gms.tku.edu.tw>, Andreas Dilger , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, visitorckw@gmail.com Subject: Re: [PATCH] ext4: improve str2hashbuf by processing 4-byte chunks Message-ID: <20251121115931.411ab538@pumpkin> In-Reply-To: <87a50flko1.fsf@igel.home> References: <20251116130105.1988020-1-409411716@gms.tku.edu.tw> <20251116193513.0f90712a@pumpkin> <20251120155816.GB13687@macsyma-3.local> <87a50flko1.fsf@igel.home> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Fri, 21 Nov 2025 11:55:26 +0100 Andreas Schwab wrote: > On Nov 20 2025, Theodore Tso wrote: > > > Secondly, it's not that a promotion happens before "any" arithmetic. > > If we add two 8-bit values together, promotion doesn't happen. > > That is not true. Integer promotion is applied individually to each > operand independent of context. True. You can think of the promotion happening every time a 'variable' is read into a cpu register for any operation (including an assignment). Similarly every write to a variable discards the high bits. David