From patchwork Thu Jul 7 08:02:45 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Antoine Tenart X-Patchwork-Id: 12909198 X-Patchwork-Delegate: kuba@kernel.org 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B16CBC433EF for ; Thu, 7 Jul 2022 08:03:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231866AbiGGIDA (ORCPT ); Thu, 7 Jul 2022 04:03:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47844 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234713AbiGGICx (ORCPT ); Thu, 7 Jul 2022 04:02:53 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 63F9833A1B for ; Thu, 7 Jul 2022 01:02:51 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 25600B81BA2 for ; Thu, 7 Jul 2022 08:02:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 53A7BC3411E; Thu, 7 Jul 2022 08:02:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1657180968; bh=mkTwEUkN8EwEpQjbJG+R6E161G0v9MVtk5qzw8dNY1M=; h=From:To:Cc:Subject:Date:From; b=awRtEdnBORIluyJ3CPM+VhTD3NvufI0XZT2H9+6+rUZeR3Du4KEX416pkp5SjbVQz NsBccXWvCWSDNGaJF673BaPPaE4yd5Bo1uN2SMdqfbNO/y9ob+/0TLeH6ISGrwIvNM G4xq0SbZAq4DL9O+kqt9aRsN/lgFCLQSBzs4Hj/HxkDrzyGWnguoaI0Ji2kxTTZ59n NiX7QJST+RSX1vVmId3909YAELeOhJzyInvqDEAfnBd8EQLUKN0ckA26hZSIPn1PUB 9tlj8Mczh7nD0wUYyD+LYB2VioeW+MJ5CjCGLBfI8yf94FMpTETEtU1shJY/ix6pOL R5gnpT31HVluw== From: Antoine Tenart To: davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, edumazet@google.com Cc: Antoine Tenart , netdev@vger.kernel.org Subject: [PATCH net-next v2] Documentation: add a description for net.core.high_order_alloc_disable Date: Thu, 7 Jul 2022 10:02:45 +0200 Message-Id: <20220707080245.180525-1-atenart@kernel.org> X-Mailer: git-send-email 2.36.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org A description is missing for the net.core.high_order_alloc_disable option in admin-guide/sysctl/net.rst ; add it. The above sysctl option was introduced by commit ce27ec60648d ("net: add high_order_alloc_disable sysctl/static key"). Thanks to Eric for running again the benchmark cited in the above commit, showing this knob is now mostly of historical importance. Cc: Eric Dumazet Signed-off-by: Antoine Tenart Reviewed-by: Eric Dumazet --- Since v1: - Reworked the documentation to mention this knob is now mostly of historical importance after Eric ran again the benchmark cited in the above commit. Documentation/admin-guide/sysctl/net.rst | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/Documentation/admin-guide/sysctl/net.rst b/Documentation/admin-guide/sysctl/net.rst index fcd650bdbc7e..805f2281e000 100644 --- a/Documentation/admin-guide/sysctl/net.rst +++ b/Documentation/admin-guide/sysctl/net.rst @@ -391,6 +391,18 @@ GRO has decided not to coalesce, it is placed on a per-NAPI list. This list is then passed to the stack when the number of segments reaches the gro_normal_batch limit. +high_order_alloc_disable +------------------------ + +By default the allocator for page frags tries to use high order pages (order-3 +on x86). While the default behavior gives good results in most cases, some users +might have hit a contention in page allocations/freeing. This was especially +true on older kernels (< 5.14) when high-order pages were not stored on per-cpu +lists. This allows to opt-in for order-0 allocation instead but is now mostly of +historical importance. + +Default: 0 + 2. /proc/sys/net/unix - Parameters for Unix domain sockets ----------------------------------------------------------