From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH 2/9] slab: remove synchronous rcu_barrier() call in memcg cache release path Date: Tue, 17 Jan 2017 09:02:15 -0800 Message-ID: <20170117170215.GC28948@mtj.duckdns.org> References: <20170114055449.11044-1-tj@kernel.org> <20170114055449.11044-3-tj@kernel.org> <20170114131939.GA2668@esperanza> <20170114151921.GA32693@mtj.duckdns.org> <20170117000754.GA25218@js1304-P5Q-DELUXE> <20170117163745.GA8352@mtj.duckdns.org> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=umpJxPbaKFmDbgYwz8dxcfODFAIHWxsf6/CbAzTPzgI=; b=f//wKVjRfuprw7sLNcmAQoDfIBGTV2QKMyo0uhasUXc47aNeNAR0uXDW2Nsok0S3MP 0WDwFLj1lbcgz/7P6s4qzITclAAbOJgdYBM1IukMzp2siwOCewrxoplKuJVhBSUME+hI fGkMfi818dZ+znMN7vdhW5A/qDwhvPX1NTuDrV/lIpMYrtYk5eXTicVbJhKOETxA+bMR stZe9nolgDtgx806cbOBeY+SuURJABJX1Qf2gU8pnxB3wiE6y+7eieVRUAwQPIJ5sHIe 79hnA7e7nKB8pieToqKTHvd/6ZcTSZbzz90QUb7u0FrnDmjl8WsDTdK/QHvQG/5fXdrm gTtg== Content-Disposition: inline In-Reply-To: <20170117163745.GA8352@mtj.duckdns.org> Sender: owner-linux-mm@kvack.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Joonsoo Kim Cc: Vladimir Davydov , cl@linux.com, penberg@kernel.org, rientjes@google.com, akpm@linux-foundation.org, jsvana@fb.com, hannes@cmpxchg.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, kernel-team@fb.com On Tue, Jan 17, 2017 at 08:37:45AM -0800, Tejun Heo wrote: > The call sequence doesn't matter. Whether you're using call_rcu() or > rcu_barrier(), you're just waiting for a grace period to pass before > continuing. It doens't give any other ordering guarantees, so the new > code should be equivalent to the old one except for being asynchronous. Oh I was confusing synchronize_rcu() with rcu_barrier(), so you're right, kmem_cache struct needs to stay around for the slab pages to be freed after RCU grace period. Will revise the patch accordingly, thanks. Thanks. -- tejun -- 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