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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 94647C3DA41 for ; Tue, 9 Jul 2024 10:04:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=pXUFjtPH2POOJIJupC1dmnTDeoRemzquo/DZzaZKD6Q=; b=3nwdkhWZ+/ZUMyCg7tnE7aubRx XwX4uh8CLgXZ6N8Rtap5tti0oGDTq6Og34g3tVJPLWrYO2h084T+rYSKtQTJFS0pzi3S8oqpr2Qcr 8LcxFj5CJ/Otv3fD+JlbUS9Y+sTnzOMhpncYLaomPHX+JFKK9YdsnqwrTw3wp64vqvc29dTf8ovSy Mt+VgoOTILjaPL8uJLCCmcYQwchfs0Z06CyaRVx0GOs7nxpvJpfUnDGLY1WgPEjYCVzK7z5wpIXpu lSAtyI6CIqzO1aEWq8KfGGUz5K5pHiW9QDMzzVpLxcbfAwR+oV7w6zWhhD7hTX170jk+anbr19koQ 6AvUYEIg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sR7hw-00000006j95-0wPM; Tue, 09 Jul 2024 10:04:24 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sR7he-00000006j0O-2Ivr for linux-arm-kernel@lists.infradead.org; Tue, 09 Jul 2024 10:04:08 +0000 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 A1B1412FC; Tue, 9 Jul 2024 03:04:30 -0700 (PDT) Received: from J2N7QTR9R3 (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D76AD3F762; Tue, 9 Jul 2024 03:04:03 -0700 (PDT) Date: Tue, 9 Jul 2024 11:04:00 +0100 From: Mark Rutland To: Linus Torvalds Cc: Christian Brauner , Al Viro , linux-fsdevel , the arch/x86 maintainers , Linux ARM , Linux Kernel Mailing List Subject: Re: FYI: path walking optimizations pending for 6.11 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240709_030406_646196_8BBF8801 X-CRM114-Status: GOOD ( 19.60 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Linus, On Wed, Jun 19, 2024 at 01:25:02PM -0700, Linus Torvalds wrote: > I've pushed out four branches based on 6.10-rc4, because I think it's > pretty ready. But I'll rebase them if people have commentary that > needs addressing, so don't treat them as some kind of stable base yet. > My plan is to merge them during the next merge window unless somebody > screams. > > The branches are: > > arm64-uaccess: > arm64: access_ok() optimization > arm64: start using 'asm goto' for put_user() > arm64: start using 'asm goto' for get_user() when available > runtime-constants: > arm64: add 'runtime constant' support > runtime constants: add x86 architecture support > runtime constants: add default dummy infrastructure > vfs: dcache: move hashlen_hash() from callers into d_hash() Apologies, the arm64 branches/patches have been on my TODO list for review/test/benchmark for the last couple of weeks, but I haven't had both the time and machine availability to do so. Looking at the arm64 runtime constants patch, I see there's a redundant store in __runtime_fixup_16(), which I think is just a leftover from applying the last roudn or feedback: +/* 16-bit immediate for wide move (movz and movk) in bits 5..20 */ +static inline void __runtime_fixup_16(__le32 *p, unsigned int val) +{ + u32 insn = le32_to_cpu(*p); + insn &= 0xffe0001f; + insn |= (val & 0xffff) << 5; + *p = insn; + *p = cpu_to_le32(insn); +} ... i.e. the first assignment to '*p' should go; the compiler should be smart enough to elide it entirely, but it shouldn't be there. For the sake of review, would you be happy to post the uaccess and runtime-constants patches to the list again? I think there might be some remaining issues with (real) PAN and we might need to do a bit more preparatory work there. Mark.