Messages in this thread | | | Subject | Re: [PATCH v3 03/28] x86/sgx: Add 'struct sgx_epc_lru_lists' to encapsulate lru list(s) | Date | Mon, 24 Jul 2023 09:55:37 -0500 | From | "Haitao Huang" <> |
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Hi Kai On Mon, 24 Jul 2023 05:04:48 -0500, Huang, Kai <kai.huang@intel.com> wrote:
> On Mon, 2023-07-17 at 08:23 -0500, Haitao Huang wrote: >> On Mon, 17 Jul 2023 07:45:36 -0500, Jarkko Sakkinen <jarkko@kernel.org> >> wrote: >> >> > On Wed Jul 12, 2023 at 11:01 PM UTC, Haitao Huang wrote: >> > > From: Kristen Carlson Accardi <kristen@linux.intel.com> >> > > >> > > Introduce a data structure to wrap the existing reclaimable list >> > > and its spinlock in a struct to minimize the code changes needed >> > > to handle multiple LRUs as well as reclaimable and non-reclaimable >> > > lists. The new structure will be used in a following set of patches >> to >> > > implement SGX EPC cgroups. > > Although briefly mentioned in the first patch, it would be better to put > more > background about the "reclaimable" and "non-reclaimable" thing here, > focusing on > _why_ we need multiple LRUs (presumably you mean two lists: reclaimable > and non- > reclaimable). > Sure I can add a little more background to introduce the reclaimable/unreclaimable concept. But why we need multiple LRUs would be self-evident in later patches, not sure I will add details here.
>> > > >> > > The changes to the structure needed for unreclaimable lists will be >> > > added in later patches. >> > > >> > > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> >> > > Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com> >> > > Signed-off-by: Haitao Huang <haitao.huang@linux.intel.com> >> > > Cc: Sean Christopherson <seanjc@google.com> >> > > >> > > V3: >> > > Removed the helper functions and revised commit messages > > Please put change history into: > > --- > change history > --- > > So it can be stripped away when applying the patch. > Will do that.
>> > > --- >> > > arch/x86/kernel/cpu/sgx/sgx.h | 17 +++++++++++++++++ >> > > 1 file changed, 17 insertions(+) >> > > >> > > diff --git a/arch/x86/kernel/cpu/sgx/sgx.h >> > > b/arch/x86/kernel/cpu/sgx/sgx.h >> > > index f6e3c5810eef..77fceba73a25 100644 >> > > --- a/arch/x86/kernel/cpu/sgx/sgx.h >> > > +++ b/arch/x86/kernel/cpu/sgx/sgx.h >> > > @@ -92,6 +92,23 @@ static inline void *sgx_get_epc_virt_addr(struct >> > > sgx_epc_page *page) >> > > return section->virt_addr + index * PAGE_SIZE; >> > > } >> > > >> > > +/* >> > > + * This data structure wraps a list of reclaimable EPC pages, and a >> > > list of >> > > + * non-reclaimable EPC pages and is used to implement a LRU policy >> > > during >> > > + * reclamation. >> > > + */ > > I'd prefer to not mention the "non-reclaimable" thing in this patch, but > defer > to the one actually introduces the "non-reclaimable" list. Actually, I > don't > think we even need this comment, given you have this in the structure: > > struct list_head reclaimable; >
Agreed.
> Which already explains the "reclaimable" list. I suppose the > non-reclaimable > list would be named similarly thus need no comment either. > > Also, I am wondering why you need to split this out as a separate > patch. It > basically does nothing. To me you should just merge this to the next > patch,
I think Kristen splitted the original patch based on Dave's comments:
https://lore.kernel.org/all/e71d76b2-4368-4627-abd4-2163e6786a20@intel.com/
> which actually does what you claimed in the changelog: > > Introduce a data structure to wrap the existing reclaimable list and > its spinlock ... > > Then this can be an infrastructure change patch, which doesn't bring any > functional change, to support the non-reclaimable list. > > >> > > +struct sgx_epc_lru_lists { >> > > + /* Must acquire this lock to access */ >> > > + spinlock_t lock; >> > >> > Isn't this self-explanatory, why the inline comment? >> >> I got a warning from the checkpatch script complaining this lock needs >> comments. > > I suspected this, so I applied this patch, removed the comment, > generated a new > patch, and run checkpatch.pl for it. It didn't report any warning/error > in my > testing. > > Are you sure you got a warning?
I did a reran and it's actually a "CHECK" I got:
$ ./scripts/checkpatch.pl --strict 0001-x86-sgx-Add-struct-sgx_epc_lru_lists-to-encapsulate-.patch CHECK: spinlock_t definition without comment #41: FILE: arch/x86/kernel/cpu/sgx/sgx.h:101: + spinlock_t lock;
total: 0 errors, 0 warnings, 1 checks, 22 lines checked
Thanks Haitao
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