Received: by 2002:ac0:bc90:0:0:0:0:0 with SMTP id a16csp225898img; Tue, 19 Mar 2019 22:42:19 -0700 (PDT) X-Google-Smtp-Source: APXvYqzPDy7dKJkkSb4DobmtK2X7NYSsqaUcf2EwwydtMKPSbca0wfTMFV/CIXohXywNgwX34bx7 X-Received: by 2002:a65:64c4:: with SMTP id t4mr5603534pgv.152.1553060539576; Tue, 19 Mar 2019 22:42:19 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1553060539; cv=none; d=google.com; s=arc-20160816; b=jTVFBPz2NAhsfweOsadk0HvFowQmbh8OF/CRI4txZfzm3gkLhpo+31Ax4N09RaZlk3 WYbDBtdiJUURB/E687dB7GtP31nOU+6i2jjNVL0KjVDFVbBLYodq8ra2lYRDXb3UKXap wZB2ABbJcFiXwtPuYmqoUW5ptd+gX2GE362Jx/ZqHAJih0LOn/V3OrKw3BD7zQTk/zvT YW3wsjdlnvCrSz343RhqPDEc4JF7knGcCGXjsxnbp0946w7vRlBu0EGnaZY2RZTT9s4j FTLOUqvnouLnZYIUKbAoGeN6WcIuu2ZYHIaH/jPefXTaEDbIjGrH0nFb6n3OvhkoY1Lq I2Bg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:user-agent:in-reply-to :content-disposition:mime-version:references:message-id:subject:cc :to:from:date; bh=4MkaN/KwaePLuv/Nf031Kjgj5PDvJTjZHh6HWs+eSEc=; b=D3uqDtl7D7TsNfJU3qapHU1WJXeTUKcSbgMKOo4a1n617qCa+klQIzz2AFRZISYlvG YnRG3NkUdw96m0R0olqSVSP2Uso2nqs+3mvMetlrn0ZOH/PRQOaJVWYn8EIVjeT8PNj2 gbHk5tGMS5+dRrk/Kg9NMNqmvGCIOar5AOqdK37GaAKjqb4QNkCaMzNbqv1Yef+jKywV 22Vqs75Hj51gXZf909lI/227OnrRCENqqL7OGlr3uCrmtkXHr6/Pi+3GVZHmy4NxoH8I NY3gZyfe+jlxX2F0cH4jd+2H4vtcuC5p8+Z4gZ9puX2YI8N6KWPyFE2/ds48xnsiGw5a UqQA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id l4si877124pgn.37.2019.03.19.22.42.04; Tue, 19 Mar 2019 22:42:19 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727513AbfCTFlS (ORCPT + 99 others); Wed, 20 Mar 2019 01:41:18 -0400 Received: from orcrist.hmeau.com ([104.223.48.154]:47156 "EHLO deadmen.hmeau.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726225AbfCTFlR (ORCPT ); Wed, 20 Mar 2019 01:41:17 -0400 Received: from gondobar.mordor.me.apana.org.au ([192.168.128.4] helo=gondobar) by deadmen.hmeau.com with esmtps (Exim 4.89 #2 (Debian)) id 1h6TyQ-00058K-Tx; Wed, 20 Mar 2019 13:41:10 +0800 Received: from herbert by gondobar with local (Exim 4.89) (envelope-from ) id 1h6TyP-00078o-W0; Wed, 20 Mar 2019 13:41:10 +0800 Date: Wed, 20 Mar 2019 13:41:09 +0800 From: Herbert Xu To: NeilBrown Cc: Thomas Graf , netdev@vger.kernel.org, "Paul E. McKenney" , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/3] rhashtable: use cmpxchg() in nested_table_alloc() Message-ID: <20190320054109.6abodcm4yyhacc5w@gondor.apana.org.au> References: <155253979234.5022.1840929790507376038.stgit@noble.brown> <155253992824.5022.10318044793639169265.stgit@noble.brown> <20190315051029.waqb3ohztl7w6zep@gondor.apana.org.au> <87lg1gocj8.fsf@notabene.neil.brown.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87lg1gocj8.fsf@notabene.neil.brown.name> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 15, 2019 at 05:51:55PM +1100, NeilBrown wrote: > > I hoped the patch could be justified on the basis that the current > behaviour is fragile - the dependency that a single spin lock covers a > while slot (and all children) in the top-level nested table is not at > all obvious. > > I do have a stronger reason though - I want the replace the spinlocks > with bit-spin-locks. With those we will only hold a lock for the > particular chain being worked on. If you need that extra explanation to > justify the patch, I'll hold it over until the other two patches land > and the rest of the bit-spin-lock series is ready. I think it would make more sense to combine this patch with your bit-spin-lock patch in a series. Thanks, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt