2022-11-11 18:49:40

by Kristen Carlson Accardi

Subject: [PATCH 04/26] x86/sgx: Use sgx_epc_lru for existing active page list

Replace the existing sgx_active_page_list and its spinlock with
a global sgx_epc_lru struct.

Signed-off-by: Sean Christopherson <[email protected]>
Signed-off-by: Kristen Carlson Accardi <[email protected]>
Cc: Sean Christopherson <[email protected]>
---
arch/x86/kernel/cpu/sgx/main.c | 39 +++++++++++++++++-----------------
1 file changed, 19 insertions(+), 20 deletions(-)

diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index ffce6fc70a1f..aa938e4d4a73 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -26,10 +26,9 @@ static DEFINE_XARRAY(sgx_epc_address_space);

/*
* These variables are part of the state of the reclaimer, and must be accessed
- * with sgx_reclaimer_lock acquired.
+ * with sgx_global_lru.lock acquired.
*/
-static LIST_HEAD(sgx_active_page_list);
-static DEFINE_SPINLOCK(sgx_reclaimer_lock);
+static struct sgx_epc_lru sgx_global_lru;

static atomic_long_t sgx_nr_free_pages = ATOMIC_LONG_INIT(0);

@@ -298,14 +297,12 @@ static void __sgx_reclaim_pages(void)
int ret;
int i;

- spin_lock(&sgx_reclaimer_lock);
+ spin_lock(&sgx_global_lru.lock);
for (i = 0; i < SGX_NR_TO_SCAN; i++) {
- if (list_empty(&sgx_active_page_list))
+ epc_page = sgx_epc_pop_reclaimable(&sgx_global_lru);
+ if (!epc_page)
break;

- epc_page = list_first_entry(&sgx_active_page_list,
- struct sgx_epc_page, list);
- list_del_init(&epc_page->list);
encl_page = epc_page->encl_owner;

if (kref_get_unless_zero(&encl_page->encl->refcount) != 0)
@@ -316,7 +313,7 @@ static void __sgx_reclaim_pages(void)
*/
epc_page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;
}
- spin_unlock(&sgx_reclaimer_lock);
+ spin_unlock(&sgx_global_lru.lock);

for (i = 0; i < cnt; i++) {
epc_page = chunk[i];
@@ -339,9 +336,9 @@ static void __sgx_reclaim_pages(void)
continue;

skip:
- spin_lock(&sgx_reclaimer_lock);
- list_add_tail(&epc_page->list, &sgx_active_page_list);
- spin_unlock(&sgx_reclaimer_lock);
+ spin_lock(&sgx_global_lru.lock);
+ sgx_epc_push_reclaimable(&sgx_global_lru, epc_page);
+ spin_unlock(&sgx_global_lru.lock);

kref_put(&encl_page->encl->refcount, sgx_encl_release);

@@ -378,7 +375,7 @@ static void sgx_reclaim_pages(void)
static bool sgx_should_reclaim(unsigned long watermark)
{
return atomic_long_read(&sgx_nr_free_pages) < watermark &&
- !list_empty(&sgx_active_page_list);
+ !list_empty(&sgx_global_lru.reclaimable);
}

/*
@@ -433,6 +430,8 @@ static bool __init sgx_page_reclaimer_init(void)

ksgxd_tsk = tsk;

+ sgx_lru_init(&sgx_global_lru);
+
return true;
}

@@ -508,10 +507,10 @@ struct sgx_epc_page *__sgx_alloc_epc_page(void)
*/
void sgx_mark_page_reclaimable(struct sgx_epc_page *page)
{
- spin_lock(&sgx_reclaimer_lock);
+ spin_lock(&sgx_global_lru.lock);
page->flags |= SGX_EPC_PAGE_RECLAIMER_TRACKED;
- list_add_tail(&page->list, &sgx_active_page_list);
- spin_unlock(&sgx_reclaimer_lock);
+ sgx_epc_push_reclaimable(&sgx_global_lru, page);
+ spin_unlock(&sgx_global_lru.lock);
}

/**
@@ -526,18 +525,18 @@ void sgx_mark_page_reclaimable(struct sgx_epc_page *page)
*/
int sgx_unmark_page_reclaimable(struct sgx_epc_page *page)
{
- spin_lock(&sgx_reclaimer_lock);
+ spin_lock(&sgx_global_lru.lock);
if (page->flags & SGX_EPC_PAGE_RECLAIMER_TRACKED) {
/* The page is being reclaimed. */
if (list_empty(&page->list)) {
- spin_unlock(&sgx_reclaimer_lock);
+ spin_unlock(&sgx_global_lru.lock);
return -EBUSY;
}

list_del(&page->list);
page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;
}
- spin_unlock(&sgx_reclaimer_lock);
+ spin_unlock(&sgx_global_lru.lock);

return 0;
}
@@ -574,7 +573,7 @@ struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim)
break;
}

- if (list_empty(&sgx_active_page_list))
+ if (list_empty(&sgx_global_lru.reclaimable))
return ERR_PTR(-ENOMEM);

if (!reclaim) {
--
2.37.3