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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id D91D4C369CB for ; Wed, 23 Apr 2025 05:54:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1CC206B0005; Wed, 23 Apr 2025 01:54:03 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1564F6B0007; Wed, 23 Apr 2025 01:54:03 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F36506B0008; Wed, 23 Apr 2025 01:54:02 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id D41AC6B0005 for ; Wed, 23 Apr 2025 01:54:02 -0400 (EDT) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 8BC0B140BC2 for ; Wed, 23 Apr 2025 05:54:02 +0000 (UTC) X-FDA: 83364242724.23.9B1A4F4 Received: from gentwo.org (gentwo.org [62.72.0.81]) by imf21.hostedemail.com (Postfix) with ESMTP id EDCB91C0007 for ; Wed, 23 Apr 2025 05:54:00 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=gentwo.org header.s=default header.b=ENzq3TRU; dmarc=pass (policy=reject) header.from=gentwo.org; spf=pass (imf21.hostedemail.com: domain of cl@gentwo.org designates 62.72.0.81 as permitted sender) smtp.mailfrom=cl@gentwo.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1745387641; a=rsa-sha256; cv=none; b=0yaLJVaz+feefYKZxGz9blJqK5P5Q8jGZ0TWaOmt44Gf3XxhUZwwGy8+UK0Lsty0wPSrr3 FFyjHiXUCtqEvs3Fws+F+GSkewopeMJ0JYP0a8aIlPjoy/WmYMVqmveczCrzWS+tiaVTFA t7sPlBAGPt4VO/ZLukvzIJm0MspV+MM= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1745387641; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=7GyqNYhjt69ZRGf9OjqOaODM0BV8u4knLCE2vz7eFrA=; b=3luqGQFRcCe4gLG4dOSvet3dVCAx7L8jyxg6QO892Q2I9JMlCEbrMEJ9Fz6611xAuUciLR XBrFBcTaUom4ElHXwuhrm9gaH+O8WEJ/7Ms59njysRLO7myWhHADq3V6E9KmluTsvPFGBP J4iHn50udXc+SYLDzFBQBsaC8v4Fscg= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=gentwo.org header.s=default header.b=ENzq3TRU; dmarc=pass (policy=reject) header.from=gentwo.org; spf=pass (imf21.hostedemail.com: domain of cl@gentwo.org designates 62.72.0.81 as permitted sender) smtp.mailfrom=cl@gentwo.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gentwo.org; s=default; t=1745387639; bh=7GyqNYhjt69ZRGf9OjqOaODM0BV8u4knLCE2vz7eFrA=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=ENzq3TRUfkcau5h9rE3F4gV4fXpg8PA87yOJTw+22edoirP2JN7diekw9pa7iu3gU 7qoAi0OUhCDFQt8W3G7tn5oOEJ+DFux1fkr8aLnKO/zAv8LBeFqyQG45qK3Lz7UR3Y c8jXaY0GnzMxrfgsIwOL2V+BZEUuHePy/YWPpqII= Received: by gentwo.org (Postfix, from userid 1003) id AA38440284; Tue, 22 Apr 2025 22:53:59 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by gentwo.org (Postfix) with ESMTP id A7C8F400CA; Tue, 22 Apr 2025 22:53:59 -0700 (PDT) Date: Tue, 22 Apr 2025 22:53:59 -0700 (PDT) From: "Christoph Lameter (Ampere)" To: Pedro Falcato cc: Harry Yoo , David Rientjes , Andrew Morton , Roman Gushchin , "Tobin C. Harding" , Alexander Viro , Matthew Wilcox , Vlastimil Babka , Dave Chinner , Rik van Riel , Andrea Arcangeli , "Liam R. Howlett" , Lorenzo Stoakes , Jann Horn , David Hildenbrand , Oscar Salvador , Michal Hocko , Byungchul Park , linux-mm@kvack.org Subject: Re: [DISCUSSION] Revisiting Slab Movable Objects In-Reply-To: Message-ID: <32b7071f-f374-ee2c-a546-9d5246003633@gentwo.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: EDCB91C0007 X-Stat-Signature: 76bnos41dirgbx4npje8mnogmpdjtc68 X-Rspam-User: X-HE-Tag: 1745387640-146652 X-HE-Meta: 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 zeIZhlQm byByBsMT/2RVr9a2EoleEXc+nOYLMnpY8fvtPIa3bVUQBQB0ZeZF0gdQI0y0XDAQ3bF0PaNkzeFFFF82Zz202FyOHLRJYblA2xxOy47eWHaC7dw1FQ/6vffVj/e/QG9/IpZq7gVkT3uFlsR5gUnIMyUpFtpntHEwZwPJ+FZ9+svoKPB4XWT8cNEvwgWGHCewxHFWZUWpPpTHPoyk5x1F8pbhaTym9Oc9OkhdUjNcSdOaiFBH7YXgELJY0kw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, 21 Apr 2025, Pedro Falcato wrote: > You can't even atomically replace a PTE without running into issues (arm requires BBM, thus > this doesn't work) so it cannot be applied to anything that can't page fault (xarray and > the maple tree are used in IRQ paths, if I'm not mistaken). Newer ARM64 processors support changing a PTE with a a new cpu feature FEAT_BBML2. An implementation has been submitted by Yang Shi and we hope that it is going to be merged for 6.17. This is a performance issue on ARM since it forces the kernel 1-1 map to be done with 4K PTEs.