On Tue, 2023-01-10 at 11:12 -0800, Hansen, Dave wrote: > On 1/9/23 18:23, Huang, Kai wrote: > > On Mon, 2023-01-09 at 16:47 -0800, Dave Hansen wrote: > > > On 1/9/23 16:40, Huang, Kai wrote: > > > > On Fri, 2023-01-06 at 11:24 -0800, Dave Hansen wrote: > > > ... > > > > > Also, tdmr_sz and max_tdmrs can both be derived from 'sysinfo'. Do they > > > > > really need to be stored here? > > > > > > > > It's not mandatory to keep them here. I did it mainly because I want to avoid > > > > passing 'sysinfo' as argument for almost all functions related to constructing > > > > TDMRs. > > > > > > I don't think it hurts readability that much. On the contrary, it makes > > > it more clear what data is needed for initialization. > > > > Sorry one thing I forgot to mention is if we keep 'tdmr_sz' in 'struct > > tdmr_info_list', it only needs to be calculated at once when allocating the > > buffer. Otherwise, we need to calculate it based on sysinfo- > > max_reserved_per_tdmr each time we want to get a TDMR at a given index. > > What's the problem with recalculating it? It is calculated like this: > > tdmr_sz = ALIGN(constant1 + constant2 * variable); > > So, what's the problem? You're concerned about too many multiplications? No problem. I don't have concern about multiplications, but since they can be avoided, I thought perhaps it's better to avoid. So I am fine with either way, no problem. > > > To me putting relevant fields (tdmrs, tdmr_sz, max_tdmrs, nr_consumed_tdmrs) > > together makes how the TDMR list is organized more clear. But please let me > > know if you prefer removing 'tdmr_sz' and 'max_tdmrs'. > > > > Btw, if we remove 'tdmr_sz' and 'max_tdmrs', even nr_consumed_tdmrs is not > > absolutely necessary here. It can be a local variable of init_tdx_module() (as > > shown in v7), and the 'struct tdmr_info_list' will only have the 'tdmrs' member > > (as you commented in v7): > > > > https://lore.kernel.org/linux-mm/cc195eb6499cf021b4ce2e937200571915bfe66f.camel@xxxxxxxxx/T/#mb9826e2bcf8bf6399c13cc5f95a948fe4b3a46d9 > > > > Please let me know what's your preference? > > I dunno. My gut says that passing sysinfo around and just deriving the > sizes values from that with helpers is the best way. 'struct > tdmr_info_list' isn't a horrible idea in and of itself, but I think it's > a confusing structure because it's not clear how the pieces fit together > when half of it is *required* and the other half is just for some kind > of perceived convenience. > Sure. No more argument about this. However, for the sake of not adding more review burden to you, how about keeping the 'struct tdmr_info_list' as is this time? Of course I am willing to remove the 'tdmr_sz' and 'max_tdmrs' from 'struct tdmr_info_list' but only keep 'tdmrs' and 'nr_consumed_tdmrs' if you are wiling or want to look at what will the new code look like. Please let me know?
