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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4C633CA9ECB for ; Thu, 31 Oct 2019 15:21:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1E06120873 for ; Thu, 31 Oct 2019 15:21:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="LQi9iZHk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728343AbfJaPVg (ORCPT ); Thu, 31 Oct 2019 11:21:36 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:34727 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728307AbfJaPVd (ORCPT ); Thu, 31 Oct 2019 11:21:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1572535292; h=from:from: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:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=KB0w+J47Vm67r8tjhUMxa0RlzCeaXYS337IcG/e9RSQ=; b=LQi9iZHkEOU+3+yN5mVUrBp9KbLSzqkUr6k6izHp0VXVLSQt4Kh0vq004FTzMDgU329RWW 0n4l1JXloysRQbFpdNuEjLyvIFPks/IZcLfWF9GTpJJXYi7CsW51pn0vahgHePsq7iEf8R kZazmhGVlUbGwO0daf7lEAxIpptAcMM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-397-MUMIyamRN_mM4zAREXjqFg-1; Thu, 31 Oct 2019 11:21:28 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 976B3107ACC0; Thu, 31 Oct 2019 15:21:26 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-121-40.rdu2.redhat.com [10.10.121.40]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9F00F60BEC; Thu, 31 Oct 2019 15:21:23 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: References: <157186182463.3995.13922458878706311997.stgit@warthog.procyon.org.uk> <157186189069.3995.10292601951655075484.stgit@warthog.procyon.org.uk> To: Konstantin Khlebnikov Cc: dhowells@redhat.com, torvalds@linux-foundation.org, Rasmus Villemoes , Greg Kroah-Hartman , Peter Zijlstra , nicolas.dichtel@6wind.com, raven@themaw.net, Christian Brauner , keyrings@vger.kernel.org, linux-usb@vger.kernel.org, linux-block@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 07/10] pipe: Conditionalise wakeup in pipe_read() [ver #2] MIME-Version: 1.0 Content-ID: <18021.1572535282.1@warthog.procyon.org.uk> Date: Thu, 31 Oct 2019 15:21:22 +0000 Message-ID: <18022.1572535282@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: MUMIyamRN_mM4zAREXjqFg-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: Konstantin Khlebnikov wrote: > > Only do a wakeup in pipe_read() if we made space in a completely full > > buffer. The producer shouldn't be waiting on pipe->wait otherwise. >=20 > We could go further and wakeup writer only when at least half of buffer i= s > empty. This gives better batching and reduces rate of context switches. >=20 > https://lore.kernel.org/lkml/157219118016.7078.16223055699799396042.stgit= @buzz/T/#u Yeah, I saw that. I suspect that where you put the slider may depend on th= e context. David