Messages in this thread | | | Date | Fri, 29 Jun 2018 14:10:30 -0700 | From | Fenghua Yu <> | Subject | Re: [PATCH v2 2/4] x86/split_lock: Align x86_capability to unsigned long to avoid split locked access |
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On Fri, Jun 29, 2018 at 01:48:45PM -0700, Dave Hansen wrote: > On 06/29/2018 01:38 PM, Fenghua Yu wrote: > > How to handle data that is used in generic code which can be used on > > non-Intel platform? For exmple, if I do this change for struct efi in > > include/linux/efi.h because set_bit() sets bits in efi.flags: > > - unsigned long flags; > > + unsigned long flags __aligned(unsigned long); > > } efi; > > > > People may argue that the alignment unnecessarily increases size of 'efi' > > on non-Intel platform which doesn't have split lock issue. Do we care this > > argument? > > Unaligned memory accesses are bad, pretty much universally. This is a > general good practice that we should have been doing anyway. Let folks > complain. Don't let it stop you. > > Also, look at the size of that structure. Look at how many pointers it > has. Do you think *anyone* is going to complain about an extra 4 bytes > in a 400-byte structure? > > > Another question, there will be a bunch of one-line changes for > > the alignment (i.e. adding __aligned(unsigned long)) in various files. > > Will the changes be put in one big patch or in separate one-liner patches? > > Just group them logically.
Sure.
Thanks.
-Fenghua
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