From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 617432FBDE2 for ; Fri, 5 Dec 2025 12:45:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764938724; cv=none; b=n+6qRLFeNco36MHrg8rr0U8AncBEmKjmOt6mxwZFVqtwZtf8MdQH/lGqSwA3KPIjr4VgcKCeFVG7Q2ydqpHwSvJ9/pQWts29rN9ciPHlj+lRKQSFHh2wRLNdzG0xxCadP6qKdI++plYj68ECmS5lUxr+EGKLEvfuQCLoBBH1W/g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764938724; c=relaxed/simple; bh=AHu6rajaGeHHXFxna+l96KDh/G4QiEzJ1hvUqbSsoQA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Gl6nOvYSn2atHMwYCJHxNHmpZ3pfunzbjNrJ1IT/560jjaa7REAGsid4epw9sHbMLhcnSTlrw1f//xO6s5rNQeYmpiHWzfm0BKTcm1ZOOQxlb3LE0Gs7ETtZjWM0BBoxNPbR2gPHcoJ6qG1Q4ja/6Z0/BjmRwe6M5d33RTCXJ9I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=GK7BmPcV; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="GK7BmPcV" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=2qiueSorp7CuL2qCIpC0CbRVrLedHc0645ZyarFGU7Q=; b=GK7BmPcVCs59pNPK2/oUMPD0Ii e8qZn6J3dQgqaXNSd4auKkLYavfhe1ya+N7wWsZTovVfcm/O7rVFK+9BcRPQeABYSf6fSHEv8NKtd BHrZR0hEngMv7+8PTCjZ4wu78TlExkN3njY2Evo6P7AW10kb7YgGGOoa5wT0Ma1kFKUBlpyEdGY2o jzpxKgMCwj//lC+a2NpboT/Ks3S4bjy9ALTPKc3YVEgX7o3w9zyManseNEoCjomKFWhK3++pl415q i6HmgScrfHV6NteLlcymBbH7/HYRj8Br+66HMZr0pYcvvUAaE0PQDfS+ctqrRddG9AnWmy+LGvKEi KbNMJ5cw==; Received: from 2001-1c00-8d85-5700-266e-96ff-fe07-7dcc.cable.dynamic.v6.ziggo.nl ([2001:1c00:8d85:5700:266e:96ff:fe07:7dcc] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1vRUJv-000000060na-0Sem; Fri, 05 Dec 2025 11:49:55 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id E3BE33003C4; Fri, 05 Dec 2025 13:45:13 +0100 (CET) Date: Fri, 5 Dec 2025 13:45:13 +0100 From: Peter Zijlstra To: Eric Dumazet Cc: Thomas Gleixner , Andy Lutomirski , linux-kernel , Eric Dumazet Subject: Re: [PATCH] entry: always inline local_irq_{enable,disable}_exit_to_user() Message-ID: <20251205124513.GZ2528459@noisy.programming.kicks-ass.net> References: <20251204153127.1321824-1-edumazet@google.com> <20251205105123.GS2528459@noisy.programming.kicks-ass.net> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Fri, Dec 05, 2025 at 02:54:26AM -0800, Eric Dumazet wrote: > On Fri, Dec 5, 2025 at 2:51 AM Peter Zijlstra wrote: > > > > On Thu, Dec 04, 2025 at 03:31:27PM +0000, Eric Dumazet wrote: > > > clang needs __always_inline instead of inline, even for tiny helpers. > > > > > > This saves some cycles in system call fast path, and saves 195 bytes > > > on x86_64 build: > > > > > > $ size vmlinux.before vmlinux.after > > > text data bss dec hex filename > > > 34652814 22291961 5875180 62819955 3be8e73 vmlinux.before > > > 34652619 22291961 5875180 62819760 3be8db0 vmlinux.after > > > > > > Signed-off-by: Eric Dumazet > > > > Yeah, sometimes these inline heuristics drive me mad. I've picked up > > this and the rseq one. I'll do something with them after rc1. > > Thanks Peter. > > I forgot to include perf numbers for this one, but apparently having a > local_irq_enable() > in an out-of-line function in syscall path was adding a 5 % penalty on > some platforms. > > Crazy... Earlier Zen with RET mitigation? ;-)