Messages in this thread | | | Subject | Re: [PATCH v5 06/18] x86/sgx: Introduce EPC page states | Date | Mon, 02 Oct 2023 23:49:42 -0500 | From | "Haitao Huang" <> |
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On Wed, 27 Sep 2023 05:28:36 -0500, Huang, Kai <kai.huang@intel.com> wrote:
> On Fri, 2023-09-22 at 20:06 -0700, Haitao Huang wrote: >> Use the lower 3 bits in the flags field of sgx_epc_page struct to >> track EPC states in its life cycle and define an enum for possible >> states. More state(s) will be added later. > > This patch does more than what the changelog claims to do. AFAICT it > does > below: > > 1) Use the lower 3 bits to track EPC page status > 2) Rename SGX_EPC_PAGE_RECLAIMER_TRACKED to SGX_EPC_PAGE_RERCLAIMABLE > 3) Introduce a new state SGX_EPC_PAGE_UNRECLAIMABLE > 4) Track SECS and VA pages as SGX_EPC_PAGE_UNRECLAIMABLE > > The changelog only says 1) IIUC. > I don't quite get why you would view 3) as a separate item from 1). In my view, 4) is not done as long as there is not separate list to track it. Maybe I should make it clear the "states" vs "tracking". States are just bits in the flags, "tracking" is done using the lists by ksgxd/cgroup. And this patch is really about "states" Would that clarify the intention of the patch?
> If we really want to do all these in one patch, then the changelog > should at > least mention the justification of all of them. > > But I don't see why 3) and 4) need to be done here. Instead, IMHO they > should > be done in a separate patch, and do it after the unreclaimable list is > introduced (or you need to bring that patch forward). > > > For instance, ... > > [snip] > >> + >> + /* Page is in use but tracked in an unreclaimable LRU list. These are >> + * only reclaimable when the whole enclave is OOM killed or the >> enclave >> + * is released, e.g., VA, SECS pages >> + * Becomes NOT_TRACKED after sgx_drop_epc() >> + */ >> + SGX_EPC_PAGE_UNRECLAIMABLE = 3, > > ... We even don't have the unreclaimable LRU list yet. It's odd to have > this > comment here. >
Yeah, I should take out the mentioning of the LRUs from definitions of the states.
Thanks Haitao
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