Messages in this thread Patch in this message | | | From | "Huang, Kai" <> | Subject | Re: [PATCH v3 03/28] x86/sgx: Add 'struct sgx_epc_lru_lists' to encapsulate lru list(s) | Date | Mon, 24 Jul 2023 10:04:48 +0000 |
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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).
> > > > > > 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.
> > > --- > > > 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;
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, 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?
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