From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from na01-bn1-obe.outbound.protection.outlook.com (mail-bn1on0131.outbound.protection.outlook.com [157.56.110.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 9A1E81A0017 for ; Tue, 27 Oct 2015 15:50:27 +1100 (AEDT) Message-ID: <1445921408.701.303.camel@freescale.com> Subject: Re: [PATCH v12 3/6] CPM/QE: use genalloc to manage CPM/QE muram From: Scott Wood To: Zhao Qiang-B45475 CC: "linux-kernel@vger.kernel.org" , "linuxppc-dev@lists.ozlabs.org" , "lauraa@codeaurora.org" , Xie Xiaobo-R63061 , "benh@kernel.crashing.org" , Li Yang-Leo-R58472 , "paulus@samba.org" Date: Mon, 26 Oct 2015 23:50:08 -0500 In-Reply-To: References: <1444806968-4627-1-git-send-email-qiang.zhao@freescale.com> <1444806968-4627-3-git-send-email-qiang.zhao@freescale.com> <1445569177.701.133.camel@freescale.com> <1445633947.701.231.camel@freescale.com> Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sun, 2015-10-25 at 22:15 -0500, Zhao Qiang-B45475 wrote: > On Sat, 2015-10-24 at 04:59 AM, Wood Scott-B07421 > wrote: > > -----Original Message----- > > From: Wood Scott-B07421 > > Sent: Saturday, October 24, 2015 4:59 AM > > To: Zhao Qiang-B45475 > > Cc: linux-kernel@vger.kernel.org; linuxppc-dev@lists.ozlabs.org; > > lauraa@codeaurora.org; Xie Xiaobo-R63061 ; > > benh@kernel.crashing.org; Li Yang-Leo-R58472 ; > > paulus@samba.org > > Subject: Re: [PATCH v12 3/6] CPM/QE: use genalloc to manage CPM/QE muram > > > > Don't send HTML e-mail. > > > > On Fri, 2015-10-23 at 02:06 -0500, Zhao Qiang-B45475 wrote: > > > On Fri, 2015-10-23 at 11:00 AM, Wood Scott-B07421 > > > > > > wrote: > > > > -----Original Message----- > > > > From: Wood Scott-B07421 > > > > Sent: Friday, October 23, 2015 11:00 AM > > > > To: Zhao Qiang-B45475 > > > > Cc: linux-kernel@vger.kernel.org; linuxppc-dev@lists.ozlabs.org; > > > > lauraa@codeaurora.org; Xie Xiaobo-R63061 ; > > > > benh@kernel.crashing.org; Li Yang-Leo-R58472 ; > > > > paulus@samba.org > > > > Subject: Re: [PATCH v12 3/6] CPM/QE: use genalloc to manage CPM/QE > > > > muram > > > > > > > > On Wed, 2015-10-14 at 15:16 +0800, Zhao Qiang wrote: > > > > > -/** > > > > > +/* > > > > > * cpm_muram_alloc - allocate the requested size worth of > > > > > multi-user > > > ram > > > > > * @size: number of bytes to allocate > > > > > * @align: requested alignment, in bytes @@ -141,59 +151,102 @@ > > > > > out: > > > > > */ > > > > > unsigned long cpm_muram_alloc(unsigned long size, unsigned long > > > > > align) { > > > > > - unsigned long start; > > > > > unsigned long flags; > > > > > - > > > > > + unsigned long start; > > > > > + static struct genpool_data_align muram_pool_data; > > > > > spin_lock_irqsave(&cpm_muram_lock, flags); > > > > > - cpm_muram_info.alignment = align; > > > > > - start = rh_alloc(&cpm_muram_info, size, "commproc"); > > > > > - memset(cpm_muram_addr(start), 0, size); > > > > > + muram_pool_data.align = align; > > > > > + gen_pool_set_algo(muram_pool, gen_pool_first_fit_align, > > > > > + &muram_pool_data); > > > > > + start = cpm_muram_alloc_common(size, &muram_pool_data); > > > > > spin_unlock_irqrestore(&cpm_muram_lock, flags); > > > > > - > > > > > return start; > > > > > } > > > > > EXPORT_SYMBOL(cpm_muram_alloc); > > > > > > > > Why is muram_pool_data static? Why is it being passed to > > > > gen_pool_set_algo()? > > > Cpm_muram use both align algo and fixed algo, so we need to set > > > corresponding algo and Algo data. > > > > The data gets passed in via gen_pool_alloc_data(). The point was to > > allow it to > > be on the caller's stack, not a long-lived data structure shared by all > > callers and > > needing synchronization. > > You mean it is not necessary to point pool->data to data, just passing the > data to gen_pool_alloc_data()? > However, the algo it needed to be set. > > > > > > > The whole reason we're adding gen_pool_alloc_data() is to avoid > > > > that. Do we need gen_pool_alloc_algo() too? > > > > > > We add gen_pool_alloc_data() to pass data to algo, because align algo > > > and fixed algo, Because align and fixed algos need specific data. > > > > And my point is that because of that, it seems like we need a version that > > accepts an algorithm as well. > > It the user just use only one algo, it doesn’t need to set algo, > However, qe_muram use two algos with alloc_align function > And alloc_fixed function. Yes. That is why gen_pool_alloc_data() does not accomplish what we want. When we were discussing gen_pool_alloc_data(), you had not yet mentioned the need for fixed allocations. -Scott