Khalid Aziz <khalid.aziz@xxxxxxxxxx> writes: > On 02/01/2018 07:29 PM, ebiederm@xxxxxxxxxxxx wrote: >> Khalid Aziz <khalid.aziz@xxxxxxxxxx> writes: >> >>> V11 changes: >>> This series is same as v10 and was simply rebased on 4.15 kernel. Can >>> mm maintainers please review patches 2, 7, 8 and 9 which are arch >>> independent, and include/linux/mm.h and mm/ksm.c changes in patch 10 >>> and ack these if everything looks good? >> >> I am a bit puzzled how this differs from the pkey's that other >> architectures are implementing to achieve a similar result. >> >> I am a bit mystified why you don't store the tag in a vma >> instead of inventing a new way to store data on page out. > > Hello Eric, > > As Steven pointed out, sparc sets tags per cacheline unlike pkey. This results > in much finer granularity for tags that pkey and hence requires larger tag > storage than what we can do in a vma. *Nod* I am a bit mystified where you keep the information in memory. I would think the tags would need to be stored per cacheline or per tlb entry, in some kind of cache that could overflow. So I would be surprised if swapping is the only time this information needs stored in memory. Which makes me wonder if you have the proper data structures. I would think an array per vma or something in the page tables would tend to make sense. But perhaps I am missing something. >> Can you please use force_sig_fault to send these signals instead >> of force_sig_info. Emperically I have found that it is very >> error prone to generate siginfo's by hand, especially on code >> paths where several different si_codes may apply. So it helps >> to go through a helper function to ensure the fiddly bits are >> all correct. AKA the unused bits all need to be set to zero before >> struct siginfo is copied to userspace. >> > > What you say makes sense. I followed the same code as other fault handlers for > sparc. I could change just the fault handlers for ADI related faults. Would it > make more sense to change all the fault handlers in a separate patch and keep > the code in arch/sparc/kernel/traps_64.c consistent? Dave M, do you have a > preference? It is my intention post -rc1 to start sending out patches to get the rest of not just sparc but all of the architectures using the new helpers. I have the code I just ran out of time befor the merge window opened to ensure everything had a good thorough review. So if you can handle the your new changes I expect I will handle the rest. Eric
