On Tue, 2015-08-25 at 03:09 -0500, Zhao Qiang-B45475 wrote: > On 08/25/2015 12:01 PM, Laura Abbott wrote: > > > -----Original Message----- > > From: Laura Abbott [mailto:labb...@redhat.com] > > Sent: Tuesday, August 25, 2015 12:01 PM > > To: Zhao Qiang-B45475; Wood Scott-B07421 > > Cc: linux-ker...@vger.kernel.org; linuxppc-dev@lists.ozlabs.org; > > lau...@codeaurora.org; Xie Xiaobo-R63061; b...@kernel.crashing.org; Li > > Yang-Leo-R58472; pau...@samba.org > > Subject: Re: [PATCH v6 1/3] genalloc:support memory-allocation with > > bytes-alignment to genalloc > > > > On 08/24/2015 07:40 PM, Zhao Qiang wrote: > > > On 08/25/2015 07:11 AM, Laura Abbott wrote: > > > > -----Original Message----- > > > > From: Laura Abbott [mailto:labb...@redhat.com] > > > > Sent: Tuesday, August 25, 2015 7:11 AM > > > > To: Zhao Qiang-B45475; Wood Scott-B07421 > > > > Cc: linux-ker...@vger.kernel.org; linuxppc-dev@lists.ozlabs.org; > > > > lau...@codeaurora.org; Xie Xiaobo-R63061; b...@kernel.crashing.org; > > > > Li Yang-Leo-R58472; pau...@samba.org > > > > Subject: Re: [PATCH v6 1/3] genalloc:support memory-allocation with > > > > bytes-alignment to genalloc > > > > > > > > On 08/24/2015 02:31 AM, 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 <qiang.z...@freescale.com> > > > > > --- > > > > > 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. > > > > > > > > > > include/linux/genalloc.h | 23 +++++++++++++++---- > > > > > lib/genalloc.c | 58 > > > > +++++++++++++++++++++++++++++++++++++++++++----- > > > > > 2 files changed, 72 insertions(+), 9 deletions(-) > > > > > > > > > > diff --git a/include/linux/genalloc.h b/include/linux/genalloc.h > > > > > index 1ccaab4..55da07e 100644 > > > > > --- a/include/linux/genalloc.h > > > > > +++ b/include/linux/genalloc.h > > > > > @@ -34,6 +34,7 @@ > > > > > > > > > > struct device; > > > > > struct device_node; > > > > > +struct gen_pool; > > > > > > > > > > /** > > > > > * Allocation callback function type definition @@ -47,7 +48,7 @@ > > > > > typedef unsigned long (*genpool_algo_t)(unsigned long *map, > > > > > unsigned long size, > > > > > unsigned long start, > > > > > unsigned int nr, > > > > > - void *data); > > > > > + void *data, struct gen_pool *pool); > > > > > > > > > > /* > > > > > * General purpose special memory pool descriptor. > > > > > @@ -73,6 +74,13 @@ struct gen_pool_chunk { > > > > > unsigned long bits[0]; /* bitmap for allocating memory > > chunk > > > > */ > > > > > }; > > > > > > > > > > +/* > > > > > + * gen_pool data descriptor for gen_pool_first_fit_align. > > > > > + */ > > > > > +struct genpool_data_align { > > > > > + int align; /* alignment by bytes for starting > > > > > address */ > > > > > +}; > > > > > + > > > > > > > > (sorry for chiming in late, I've been traveling) > > > > > > > > Is there an advantage here to wrapping this in a structure instead of > > > > just passing a pointer to an align integer? > > > > > > > > > Please look at the commit message for > > > ca279cf1065fb689abea1dc7d8c11787729bb185 which adds "data": > > > > > > "As I can't predict all the possible requirements/needs for all > > > allocation uses cases, I add a "free" field 'void *data' to pass any > > > needed information to the allocation function. For example 'data' > > > could be used to handle a structure where you store the alignment, the > > > expected memory bank, the requester device, or any information that > > > could influence the allocation algorithm." > > > > > > > Right, I understand what the purpose is but I'm not sure what you're > > getting from the structure vs passing a pointer, e.g. > > > > int align; > > > > align = 4; > > > > gen_pool_alloc_data(&pool, size, &align); > > > > it just seems to obfuscate what's going on by wrapping a single integer > > in a structure that's narrowly defined in a generic function right now. I > > guess it could change later which would necessitate having the structure > > but again it's so generic I'm not sure what else you would pass that > > would be applicable to all clients. > > Scott and me have discussed about this issue in my RFC patch. > Please review: http://patchwork.ozlabs.org/patch/493297/
I don't see anything relevant in that discussion. I tend to favor always using a struct for this type of opaque data, for consistency and extendability, but in this case it really doesn't matter much either way. -Scott _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
