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 AAB3BC61DB9 for ; Thu, 27 Aug 2026 19:05:11 +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:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=l0/18a+jAXPQl28qEPQ6uj9wzdNRM90aKlsTE3XVMSs=; b=28/kbfcgRrnwct/sTBimR3C09H NM4yzE2UhENLRPj3Utleq4maLf1smukUnuP2U1sp1bb4nFw/tCAJau42O+S4sdJM/tgLDcpZIDywm 84A2dY5kbEoLcaSKWjs5peB4SqZrf6zN0jSQ0yDdkcNxRg1eYUzjQaK7RG8IZjbik7LaHl+gx6Htu ZLbfqRY5PD4PJJMN9BB+GrPNjrfb6np78xmsaPwL1TMokJfrq5J+mB7WGp5f2VHARXruzraN4ILN4 CDyf2vRM1PEXv0yDcFmkX+TjdNgjoM7Qc0DR6f2EhdEOh3EIjPzHJQJm2ovSZaVwcIHvnhzCH8bTw 62+Y4mDA==; 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charset=UTF-8 Content-Transfer-Encoding: 7bit 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 [...] About to go on PTO, some random points :) > >> [12] - Optimize this_cpu_*() ops for non-x86 (ARM64 for this series) >> >> As of today, none of it was merged into mainline. > > I mean :) maybe take that as a hint? If a number of series trying to do X get > rejected by upstream, that is maybe suggestive of barking up the wrong tree? I'd have expected an explanation at that point why previous approaches were not merged and how this patch set is sufficiently different that it is worth maintainer's time. > >> However, after thorough re-evaluation, we were not able to observe >> performance improvement for the x86 platform, so we have decided to stop this >> direction and switch on arm64. > > I mean, why? You should provide details here, this is quite hand-wavey. You are > also proposing core mm changes for something that seems specific to unique > hardware as far as I can tell, which is a big ask. What I consider interesting is "after thorough re-evaluation, we were not able to observe performance improvement for the x86 platform". How confident are we that a thorough re-evaluation on arm64 will not similarly have the same outcome? IOW, what was the problematic part when doing the x86 evaluation, and how was that avoided when evaluating the arm64 implementation? -- Cheers, David