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From:   Kristen Carlson Accardi <kristen@linux.intel.com>
To:     jarkko@kernel.org, dave.hansen@linux.intel.com, tj@kernel.org,
        linux-kernel@vger.kernel.org, linux-sgx@vger.kernel.org,
        cgroups@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>
Cc:     zhiquan1.li@intel.com,
        Kristen Carlson Accardi <kristen@linux.intel.com>,
        Sean Christopherson <seanjc@google.com>
Subject: [PATCH v2 09/18] x86/sgx: Return the number of EPC pages that were successfully reclaimed
Date:   Fri,  2 Dec 2022 10:36:45 -0800
Message-Id: <20221202183655.3767674-10-kristen@linux.intel.com>
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From: Sean Christopherson <sean.j.christopherson@intel.com>

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@intel.com>
Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Cc: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kernel/cpu/sgx/main.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index f201ca85212f..a4a65eadfb79 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -291,7 +291,7 @@ static void sgx_reclaimer_write(struct sgx_epc_page *epc_page,
  * problematic as it would increase the lock contention too much, which would
  * halt forward progress.
  */
-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_epc_page *epc_page, *tmp;
@@ -326,7 +326,7 @@ static void __sgx_reclaim_pages(int nr_to_scan)
 	spin_unlock(&sgx_global_lru.lock);
 
 	if (list_empty(&iso))
-		return;
+		return 0;
 
 	i = 0;
 	list_for_each_entry_safe(epc_page, tmp, &iso, list) {
@@ -374,12 +374,16 @@ static void __sgx_reclaim_pages(int nr_to_scan)
 
 		sgx_free_epc_page(epc_page);
 	}
+	return i;
 }
 
-static void sgx_reclaim_pages(int nr_to_scan)
+static int sgx_reclaim_pages(int nr_to_scan)
 {
-	__sgx_reclaim_pages(nr_to_scan);
+	int ret;
+
+	ret = __sgx_reclaim_pages(nr_to_scan);
 	cond_resched();
+	return ret;
 }
 
 static bool sgx_should_reclaim(unsigned long watermark)
-- 
2.38.1