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 A9F44D43369 for ; Fri, 12 Dec 2025 04:27:32 +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: MIME-Version:Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=n8na/ke9IE9q1bAVsI7+ErdZjhBbX1mnOYIQbX9UWUE=; b=oW3L2sL8px0WwfnQXt2p43jwmr HTIUOritfqSl54EJ+tV4WYy3v22sLqsRxXvbavXw5Yfq4XozAPTL3XZHKKC/KpYkRpX3TJp4sWYf6 VQD+qaCPkpPDfxVuNdIjQY9+71gq2o+13Bv292qjSDtK2dbjLU58ZqKFjB6ZDiYebDENtr1P8NTzZ i9Twj3fX9Gpj42QVt9TN4brZFfK6xCXHYk15RnnfaGdPz+lJt6LESEdVEO6uXwcaiQsMoGvmVfQb6 CXQ9Gj66PrOirhsp2f86GjECFAi3gMX8N/Anfl/cmN+/IzyNrq2jUSqHFqibhw4wrQAhi3BzZouao Yf2OlWUA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vTukV-0000000049d-15fS; Fri, 12 Dec 2025 04:27:23 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vTukS-0000000049D-0qGw for linux-arm-kernel@lists.infradead.org; Fri, 12 Dec 2025 04:27:21 +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 516231063; Thu, 11 Dec 2025 20:27:08 -0800 (PST) Received: from MacBook-Pro.blr.arm.com (MacBook-Pro.blr.arm.com [10.164.18.59]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id AD4853F762; Thu, 11 Dec 2025 20:27:09 -0800 (PST) From: Dev Jain To: catalin.marinas@arm.com, will@kernel.org, urezki@gmail.com, akpm@linux-foundation.org, tytso@mit.edu, adilger.kernel@dilger.ca, cem@kernel.org Cc: ryan.roberts@arm.com, anshuman.khandual@arm.com, shijie@os.amperecomputing.com, yang@os.amperecomputing.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, npiggin@gmail.com, willy@infradead.org, david@kernel.org, ziy@nvidia.com, Dev Jain Subject: [RESEND RFC PATCH 0/2] Enable vmalloc huge mappings by default on arm64 Date: Fri, 12 Dec 2025 09:56:59 +0530 Message-Id: <20251212042701.71993-1-dev.jain@arm.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251211_202720_279073_2D838656 X-CRM114-Status: UNSURE ( 9.33 ) X-CRM114-Notice: Please train this message. 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 In the quest for reducing TLB pressure via block mappings, enable huge vmalloc by default on arm64 for BBML2-noabort systems which support kernel live mapping split. This series is an RFC, because I cannot get a performance improvement for the usual benchmarks which we have. Currently, vmalloc follows an opt-in approach for block mappings - the users calling vmalloc_huge() are the ones which expect the most advantage from block mappings. Most users of vmalloc(), kvmalloc() and kvzalloc() map a single page. After applying this series, it is expected that a considerable number of users will produce cont mappings, and probably none will produce PMD mappings. I am asking for help from the community in testing - I believe that one of the testing methods is xfstests: a lot of code uses the APIs mentioned above. I am hoping that someone can jump in and run at least xfstests, and probably some other tests which can take advantage of the reduced TLB pressure from vmalloc cont mappings. --- Patchset applies on Linus' master (d358e5254674). Dev Jain (2): mm/vmalloc: Do not align size to huge size arm64/mm: Enable huge-vmalloc by default arch/arm64/include/asm/vmalloc.h | 6 +++++ arch/arm64/mm/pageattr.c | 4 +-- include/linux/vmalloc.h | 7 ++++++ mm/vmalloc.c | 43 +++++++++++++++++++++++++------- 4 files changed, 48 insertions(+), 12 deletions(-) -- 2.30.2