From mboxrd@z Thu Jan 1 00:00:00 1970 From: Phil Sutter Subject: Re: [PATCH v2 0/4] improve fault-tolerance of rhashtable runtime-test Date: Mon, 30 Nov 2015 11:14:01 +0100 Message-ID: <20151130101401.GA17712@orbit.nwl.cc> References: <1448039840-11367-1-git-send-email-phil@nwl.cc> <20151130093755.GA8159@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, tgraf@suug.ch, fengguang.wu@intel.com, wfg@linux.intel.com, lkp@01.org To: Herbert Xu Return-path: Content-Disposition: inline In-Reply-To: <20151130093755.GA8159@gondor.apana.org.au> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Mon, Nov 30, 2015 at 05:37:55PM +0800, Herbert Xu wrote: > Phil Sutter wrote: > > The following series aims to improve lib/test_rhashtable in different > > situations: > > > > Patch 1 allows the kernel to reschedule so the test does not block too > > long on slow systems. > > Patch 2 fixes behaviour under pressure, retrying inserts in non-permanent > > error case (-EBUSY). > > Patch 3 auto-adjusts the upper table size limit according to the number > > of threads (in concurrency test). In fact, the current default is > > already too small. > > Patch 4 makes it possible to retry inserts even in supposedly permanent > > error case (-ENOMEM) to expose rhashtable's remaining problem of > > -ENOMEM being not as permanent as it is expected to be. > > I'm sorry but this patch series is simply bogus. The whole series?! > If rhashtable is indeed returning such errors under normal > conditions then rhashtable is broken and we must fix it instead > of working around it in the test code! You're stating the obvious. Remember, the reason I prepared patch 4 was because you wanted to fix just that bug in rhashtable in the first place. Just to make this clear: Patches 1-3 are reasonable on their own, the only connection to the bug is that patch 2 makes it visible (at least on my system it wasn't before). > FWIW I still haven't been able to reproduce this problem, perhaps > because my machines have too few CPUs? Did you try with my bogus patch series applied? How many CPUs does your test system actually have? > So can someone please help me reproduce this? Because just loading > test_rhashtable isn't doing it. As said, maybe you need to increase the number of spawned threads (tcount=50 or so). Cheers, Phil