From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from na01-bl2-obe.outbound.protection.outlook.com (mail-bl2on0103.outbound.protection.outlook.com [65.55.169.103]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 5EB311A2AF3 for ; Fri, 11 Sep 2015 08:07:13 +1000 (AEST) Message-ID: <1441922820.2909.10.camel@freescale.com> Subject: Re: [PATCH V7 1/3] genalloc:support memory-allocation with bytes-alignment to genalloc 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: Thu, 10 Sep 2015 17:07:00 -0500 In-Reply-To: References: <1441011520-15424-1-git-send-email-qiang.zhao@freescale.com> <1441153816.4966.109.camel@freescale.com> <1441160299.4966.122.camel@freescale.com> <1441816660.29081.7.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 Wed, 2015-09-09 at 21:26 -0500, Zhao Qiang-B45475 wrote: > On Wed, 2015-09-10 at 12:38AM -0500, Wood Scott-B07421 wrote: > > -----Original Message----- > > From: Wood Scott-B07421 > > Sent: Thursday, September 10, 2015 12:38 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 V7 1/3] genalloc:support memory-allocation with > > bytes-alignment to genalloc > > > > On Sat, 2015-09-05 at 22:13 -0500, Zhao Qiang-B45475 wrote: > > > On Wed, 2015-09-02 at 10:18AM +0800, Wood Scott-B07421 wrote: > > > > -----Original Message----- > > > > From: Wood Scott-B07421 > > > > Sent: Wednesday, September 02, 2015 10:18 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 V7 1/3] genalloc:support memory-allocation with > > > > bytes-alignment to genalloc > > > > > > > > On Tue, 2015-09-01 at 21:10 -0500, Zhao Qiang-B45475 wrote: > > > > > On Wed, 2015-09-02 at 08:38AM +0800, Wood Scott-B07421 wrote: > > > > > > -----Original Message----- > > > > > > From: Wood Scott-B07421 > > > > > > Sent: Wednesday, September 02, 2015 8:30 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 V7 1/3] genalloc:support memory-allocation > > > > > > with bytes-alignment to genalloc > > > > > > > > > > > > On Mon, 2015-08-31 at 16:58 +0800, Zhao Qiang wrote: > > > > > > > Bytes alignment is required to manage some special RAM, so add > > > > > > > gen_pool_first_fit_align to genalloc, meanwhile add > > > > > > > gen_pool_alloc_data to pass data to > > > > > > > gen_pool_first_fit_align(modify gen_pool_alloc as a wrapper) > > > > > > > > > > > > > > Signed-off-by: Zhao Qiang > > > > > > > --- > > > > > > > Changes for v6: > > > > > > > - patches set v6 include a new patch because of using > > > > > > > - genalloc to manage QE MURAM, patch 0001 is the new > > > > > > > - patch, adding bytes alignment for allocation for use. > > > > > > > Changes for v7: > > > > > > > - cpm muram also need to use genalloc to manage, it has > > > > > > > a function to reserve a specific region of muram, > > > > > > > add offset to genpool_data for start addr to be > > allocated. > > > > > > > > > > > > This seems to be describing more than just the changes in this > > patch. > > > > > > What does also handling cpm have to do with this patch? Are you > > > > > > adding support for reserving a specific region in this patch? I > > > > > > don't see it, and in any case it should go in a different patch. > > > > > > > > > > Yes, I added. The code below can support the function. > > > > > offset_bit = (alignment->offset + (1UL << order) - 1) >> > > order; > > > > > return bitmap_find_next_zero_area(map, size, start + > > > > > offset_bit, > > > > nr, > > > > > align_mask); > > > > > > > > > > CPM has an function cpm_muram_alloc_fixed, needing to allocate > > > > > muram from a Specific offset. So I add the code and add offset to > > struct data. > > > > > > > > I thought the offset was related to the previous discussion of > > > > checking for allocation failure. Are you using it to implement > > > > alloc_fixed()? If so, please don't. Besides the awkward > > > > implementation (what does it logically have to do with > > > > gen_pool_first_fit_align?), it does not appear to be correct - > > > > - what happens with multiple chunks? What happens if part of the > > > > region the caller is trying to reserve is already taken? Implement > > > > a proper function to reserve a fixed genalloc region. > > > > > > > The offset is which allocation block address need to be larger than, > > > Not equal to, it really like the parameter start of the algo(the > > > bitnumber To start searching at). > > > > cpm_muram_alloc_fixed() is not "search starting at this offset". It is > > "reserve this exact range or fail". > > Yes, you are right! How about to add a new algo into genalloc to search > At offset, then handle it in muram layer, if the address return from > genalloc > Is not equal to offset, return negative number? If you're adding a new algorithm, why not make it actually do what you want rather than adding something different and fixing it up in the caller? -Scott