From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f200.google.com (mail-pf0-f200.google.com [209.85.192.200]) by kanga.kvack.org (Postfix) with ESMTP id B748A6B038A for ; Sat, 18 Mar 2017 12:37:39 -0400 (EDT) Received: by mail-pf0-f200.google.com with SMTP id n11so12144171pfg.7 for ; Sat, 18 Mar 2017 09:37:39 -0700 (PDT) Received: from helcar.apana.org.au (helcar.hengli.com.au. [209.40.204.226]) by mx.google.com with ESMTPS id z7si8564669pff.69.2017.03.18.09.37.36 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 18 Mar 2017 09:37:38 -0700 (PDT) Date: Sun, 19 Mar 2017 00:37:02 +0800 From: Herbert Xu Subject: Re: [PATCH 0/5] mm subsystem refcounter conversions Message-ID: <20170318163702.GA23796@gondor.apana.org.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170228172156.de13fdc41a3ca6a4deea7750@linux-foundation.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: elena.reshetova@intel.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, peterz@infradead.org, gregkh@linuxfoundation.org, viro@zeniv.linux.org.uk, catalin.marinas@arm.com, mingo@redhat.com, arnd@arndb.de, luto@kernel.org, "David S. Miller" , netdev@vger.kernel.org Andrew Morton wrote: > > The performance implications of this proposal are terrifying. > > I suggest adding a set of non-debug inlined refcount functions which > just fall back to the simple atomic.h operations. > > And add a new CONFIG_DEBUG_REFCOUNT. So the performance (and code > size!) with CONFIG_DEBUG_REFCOUNT=n is unaltered from present code. > And make CONFIG_DEBUG_REFCOUNT suitably difficult to set. I agree. Refcounts are used in many performance-critical sites within the network subsystem. Thanks, -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org