[RFC PATCH 10/20] x86/sgx: Return the number of EPC pages that were successfully reclaimed

Kristen Carlson Accardi
2022-09-22T17:10:47Z

From: Sean Christopherson <sean.j.christopherson-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>

Return the number of reclaimed pages from sgx_reclaim_pages(), the EPC
cgroup will use the result to track the success rate of its reclaim
calls, e.g. to escalate to a more forceful reclaiming mode if necessary.

Signed-off-by: Sean Christopherson <sean.j.christopherson-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Signed-off-by: Kristen Carlson Accardi <kristen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
Cc: Sean Christopherson <seanjc-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
---
arch/x86/kernel/cpu/sgx/main.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 0010ed1b2e98..fc5aed813834 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -290,8 +290,10 @@ static void sgx_reclaimer_write(struct sgx_epc_page *epc_page,
* + EWB) but not sufficiently. Reclaiming one page at a time would also be
* problematic as it would increase the lock contention too much, which would
* halt forward progress.
+ *
+ * Return: number of EPC pages reclaimed
*/
-static void sgx_reclaim_pages(int nr_to_scan)
+static int sgx_reclaim_pages(int nr_to_scan)
{
struct sgx_backing backing[SGX_MAX_NR_TO_RECLAIM];
struct sgx_encl_page *encl_page;
@@ -373,6 +375,7 @@ static void sgx_reclaim_pages(int nr_to_scan)
}
out:
cond_resched();
+ return i;
}

static bool sgx_should_reclaim(unsigned long watermark)
--
2.37.3