linux-kernel - [RFC PATCH 01/20] x86/sgx: Call cond_resched() at the end of sgx_reclaim

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Message-Id: <20220922171057.1236139-2-kristen@linux.intel.com>
Date:   Thu, 22 Sep 2022 10:10:38 -0700
From:   Kristen Carlson Accardi <kristen@...ux.intel.com>
To:     linux-kernel@...r.kernel.org, linux-sgx@...r.kernel.org,
        cgroups@...r.kernel.org, Jarkko Sakkinen <jarkko@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        x86@...nel.org, "H. Peter Anvin" <hpa@...or.com>
Cc:     Kristen Carlson Accardi <kristen@...ux.intel.com>,
        Sean Christopherson <seanjc@...gle.com>
Subject: [RFC PATCH 01/20] x86/sgx: Call cond_resched() at the end of sgx_reclaim_pages()

From: Sean Christopherson <sean.j.christopherson@...el.com>

Move the invocation of post-reclaim cond_resched() from the callers of
sgx_reclaim_pages() into the reclaim path itself.   sgx_reclaim_pages()
is always called in a loop and is always followed by a call to
cond_resched().  This will hold true for the EPC cgroup as well, which
adds even more calls to sgx_reclaim_pages() and thus cond_resched().

Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
Signed-off-by: Kristen Carlson Accardi <kristen@...ux.intel.com>
Cc: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kernel/cpu/sgx/main.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 515e2a5f25bb..4cdeb915dc86 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -367,6 +367,8 @@ static void sgx_reclaim_pages(void)
 
 		sgx_free_epc_page(epc_page);
 	}
+
+	cond_resched();
 }
 
 static bool sgx_should_reclaim(unsigned long watermark)
@@ -410,8 +412,6 @@ static int ksgxd(void *p)
 
 		if (sgx_should_reclaim(SGX_NR_HIGH_PAGES))
 			sgx_reclaim_pages();
-
-		cond_resched();
 	}
 
 	return 0;
@@ -578,7 +578,6 @@ struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim)
 		}
 
 		sgx_reclaim_pages();
-		cond_resched();
 	}
 
 	if (sgx_should_reclaim(SGX_NR_LOW_PAGES))
-- 
2.37.3