On Tue Jan 30, 2024 at 4:09 AM EET, Haitao Huang wrote:
> From: Kristen Carlson Accardi <kristen@xxxxxxxxxxxxxxx>
>
> The functions, sgx_{mark,unmark}_page_reclaimable(), manage the tracking
> of reclaimable EPC pages: sgx_mark_page_reclaimable() adds a newly
> allocated page into the global LRU list while
> sgx_unmark_page_reclaimable() does the opposite. Abstract the hard coded
> global LRU references in these functions to make them reusable when
> pages are tracked in per-cgroup LRUs.
>
> Create a helper, sgx_lru_list(), that returns the LRU that tracks a given
> EPC page. It simply returns the global LRU now, and will later return
> the LRU of the cgroup within which the EPC page was allocated. Replace
> the hard coded global LRU with a call to this helper.
>
> Next patches will first get the cgroup reclamation flow ready while
> keeping pages tracked in the global LRU and reclaimed by ksgxd before we
> make the switch in the end for sgx_lru_list() to return per-cgroup
> LRU.
>
> Co-developed-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
> Signed-off-by: Kristen Carlson Accardi <kristen@xxxxxxxxxxxxxxx>
> Co-developed-by: Haitao Huang <haitao.huang@xxxxxxxxxxxxxxx>
> Signed-off-by: Haitao Huang <haitao.huang@xxxxxxxxxxxxxxx>
> ---
> V7:
> - Split this out from the big patch, #10 in V6. (Dave, Kai)
> ---
> arch/x86/kernel/cpu/sgx/main.c | 30 ++++++++++++++++++------------
> 1 file changed, 18 insertions(+), 12 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
> index 912959c7ecc9..a131aa985c95 100644
> --- a/arch/x86/kernel/cpu/sgx/main.c
> +++ b/arch/x86/kernel/cpu/sgx/main.c
> @@ -32,6 +32,11 @@ static DEFINE_XARRAY(sgx_epc_address_space);
> */
> static struct sgx_epc_lru_list sgx_global_lru;
>
> +static inline struct sgx_epc_lru_list *sgx_lru_list(struct sgx_epc_page *epc_page)
> +{
> + return &sgx_global_lru;
> +}
> +
> static atomic_long_t sgx_nr_free_pages = ATOMIC_LONG_INIT(0);
>
> /* Nodes with one or more EPC sections. */
> @@ -500,25 +505,24 @@ struct sgx_epc_page *__sgx_alloc_epc_page(void)
> }
>
> /**
> - * sgx_mark_page_reclaimable() - Mark a page as reclaimable
> + * sgx_mark_page_reclaimable() - Mark a page as reclaimable and track it in a LRU.
> * @page: EPC page
> - *
> - * Mark a page as reclaimable and add it to the active page list. Pages
> - * are automatically removed from the active list when freed.
> */
> void sgx_mark_page_reclaimable(struct sgx_epc_page *page)
> {
> - spin_lock(&sgx_global_lru.lock);
> + struct sgx_epc_lru_list *lru = sgx_lru_list(page);
> +
> + spin_lock(&lru->lock);
> page->flags |= SGX_EPC_PAGE_RECLAIMER_TRACKED;
> - list_add_tail(&page->list, &sgx_global_lru.reclaimable);
> - spin_unlock(&sgx_global_lru.lock);
> + list_add_tail(&page->list, &lru->reclaimable);
> + spin_unlock(&lru->lock);
> }
>
> /**
> - * sgx_unmark_page_reclaimable() - Remove a page from the reclaim list
> + * sgx_unmark_page_reclaimable() - Remove a page from its tracking LRU
> * @page: EPC page
> *
> - * Clear the reclaimable flag and remove the page from the active page list.
> + * Clear the reclaimable flag if set and remove the page from its LRU.
> *
> * Return:
> * 0 on success,
> @@ -526,18 +530,20 @@ void sgx_mark_page_reclaimable(struct sgx_epc_page *page)
> */
> int sgx_unmark_page_reclaimable(struct sgx_epc_page *page)
> {
> - spin_lock(&sgx_global_lru.lock);
> + struct sgx_epc_lru_list *lru = sgx_lru_list(page);
> +
> + spin_lock(&lru->lock);
> if (page->flags & SGX_EPC_PAGE_RECLAIMER_TRACKED) {
> /* The page is being reclaimed. */
> if (list_empty(&page->list)) {
> - spin_unlock(&sgx_global_lru.lock);
> + spin_unlock(&lru->lock);
> return -EBUSY;
> }
>
> list_del(&page->list);
> page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;
> }
> - spin_unlock(&sgx_global_lru.lock);
> + spin_unlock(&lru->lock);
>
> return 0;
> }
Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
BR, Jarkko
