From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-f69.google.com (mail-lf0-f69.google.com [209.85.215.69]) by kanga.kvack.org (Postfix) with ESMTP id 3ADAD6B0262 for ; Wed, 8 Jun 2016 11:06:57 -0400 (EDT) Received: by mail-lf0-f69.google.com with SMTP id h68so5470212lfh.2 for ; Wed, 08 Jun 2016 08:06:57 -0700 (PDT) Received: from mail-wm0-f47.google.com (mail-wm0-f47.google.com. [74.125.82.47]) by mx.google.com with ESMTPS id x80si32184370wme.118.2016.06.08.08.06.55 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 08 Jun 2016 08:06:56 -0700 (PDT) Received: by mail-wm0-f47.google.com with SMTP id m124so21431443wme.1 for ; Wed, 08 Jun 2016 08:06:55 -0700 (PDT) Date: Wed, 8 Jun 2016 17:06:54 +0200 From: Michal Hocko Subject: Re: [PATCH] mm: memcontrol: remove BUG_ON in uncharge_list Message-ID: <20160608150653.GP22570@dhcp22.suse.cz> References: <1465369248-13865-1-git-send-email-roy.qing.li@gmail.com> <20160608072554.GD22570@dhcp22.suse.cz> <20160608145833.GA6727@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160608145833.GA6727@cmpxchg.org> Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner Cc: cgroups@vger.kernel.org, linux-mm@kvack.org, roy.qing.li@gmail.com, vdavydov@virtuozzo.com On Wed 08-06-16 10:58:33, Johannes Weiner wrote: > On Wed, Jun 08, 2016 at 09:25:54AM +0200, Michal Hocko wrote: > > On Wed 08-06-16 15:00:48, roy.qing.li@gmail.com wrote: > > > From: Li RongQing > > > > > > when call uncharge_list, if a page is transparent huge, and not need to > > > BUG_ON about non-transparent huge, since nobody should be be seeing the > > > page at this stage and this page cannot be raced with a THP split up > > > > Johannes do you remember why you have kept this bug on even after > > 0a31bc97c80c ("mm: memcontrol: rewrite uncharge API")? > > No, I just copied it over without thinking too much about it. That > patch was pretty drastic, so why not keep the sanity checks in case > one of the many assumptions it made were flawed... Yeah the VM_BUG_ON made sense before because the charge could have gone away while the page could be visible, thus split. > But it's probably okay to drop it at this point. Thanks for double checking. I was just not sure I didn't miss anything. I am always a bit nervous when bug_ons a removed. > > > Signed-off-by: Li RongQing > > Acked-by: Johannes Weiner With the reference to the rewrite which made it pointless Acked-by: Michal Hocko -- Michal Hocko SUSE Labs -- 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