> -----Original Message----- > From: Wood Scott-B07421 > Sent: Wednesday, August 26, 2015 12:23 AM > To: Zhao Qiang-B45475 > Cc: Laura Abbott; linux-ker...@vger.kernel.org; linuxppc- > d...@lists.ozlabs.org; lau...@codeaurora.org; Xie Xiaobo-R63061; > b...@kernel.crashing.org; Li Yang-Leo-R58472; pau...@samba.org > Subject: Re: [PATCH v6 3/3] qe_common: add qe_muram_ functions to manage > muram > > On Tue, 2015-08-25 at 02:19 -0500, Zhao Qiang-B45475 wrote: > > On 08/25/2015 12:15 PM, Laura Abbott wrote > > > -----Original Message----- > > > From: Laura Abbott [mailto:labb...@redhat.com] > > > Sent: Tuesday, August 25, 2015 12:15 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 3/3] qe_common: add qe_muram_ functions to > > > manage muram > > > > > > On 08/24/2015 08:03 PM, Zhao Qiang wrote: > > > > > > > > > -----Original Message----- > > > > > From: Laura Abbott [mailto:labb...@redhat.com] > > > > > Sent: Tuesday, August 25, 2015 7:32 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 3/3] qe_common: add qe_muram_ functions > > > > > to manage muram > > > > > > > > > > There doesn't seem to be a check for allocation failure from the > > > > > gen_alloc. > > > > > > > > gen_pool_alloc will return 0 if there is error, but if the address > > > > returned is just 0x0, it can't distinguish it is address or error. > > > > > > > > > > Yes, that's a bad limitation of gen_pool. Maybe one day that will > > > get fixed. > > > In a previous out of tree driver, I worked around this by offsetting > > > the gen_pool_add by a constant so any return value was non-zero and > > > out of memory was zero and then subtracting the constant off of the > return value. > > > Not sure if that's better or worse than just fixing gen_alloc. > > > > > > > The workaround works for non alignment allocation, but for alignment > > allocation, It need to align bytes to addr 0, offsetting the > > gen_pool_add maybe make wrong alignment > > It would work if the offset you add is a multiple of the size of muram.
The QE apps ask different bytes alignment for different use due to hardware restriction. Why don’t we deal with it in gen_pool_alloc func instead of a workaround? It is more reasonable. > > -Scott _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
