diff mbox series

[v2,08/18] x86/sgx: Allow reclaiming up to 32 pages, but scan 16 by default

Message ID 20221202183655.3767674-9-kristen@linux.intel.com
State New
Headers
Series Add Cgroup support for SGX EPC memory |

Commit Message

Kristen Carlson Accardi Dec. 2, 2022, 6:36 p.m. UTC 
  From: Sean Christopherson <sean.j.christopherson@intel.com>

Modify sgx_reclaim_pages() to take a parameter that specifies the
number of pages to scan for reclaiming. Specify a max value of
32, but scan 16 in the usual case. This allows the number of pages
sgx_reclaim_pages() scans to be specified by the caller, and adjusted
in future patches.

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 | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

Comments

Jarkko Sakkinen Dec. 8, 2022, 9:26 a.m. UTC | #1 
On Fri, Dec 02, 2022 at 10:36:44AM -0800, Kristen Carlson Accardi wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
> 
> Modify sgx_reclaim_pages() to take a parameter that specifies the
> number of pages to scan for reclaiming. Specify a max value of
> 32, but scan 16 in the usual case. This allows the number of pages
> sgx_reclaim_pages() scans to be specified by the caller, and adjusted
> in future patches.
> 
> 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 | 25 +++++++++++++++----------
>  1 file changed, 15 insertions(+), 10 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
> index 83aaf5cea7b9..f201ca85212f 100644
> --- a/arch/x86/kernel/cpu/sgx/main.c
> +++ b/arch/x86/kernel/cpu/sgx/main.c
> @@ -18,6 +18,8 @@
>  #include "encl.h"
>  #include "encls.h"
>  
> +#define SGX_MAX_NR_TO_RECLAIM	32

SGX_NR_TO_SCAN_MAX

BR, Jarkko
Jarkko Sakkinen Dec. 8, 2022, 9:27 a.m. UTC | #2 
On Thu, Dec 08, 2022 at 09:26:35AM +0000, Jarkko Sakkinen wrote:
> On Fri, Dec 02, 2022 at 10:36:44AM -0800, Kristen Carlson Accardi wrote:
> > From: Sean Christopherson <sean.j.christopherson@intel.com>
> > 
> > Modify sgx_reclaim_pages() to take a parameter that specifies the
> > number of pages to scan for reclaiming. Specify a max value of
> > 32, but scan 16 in the usual case. This allows the number of pages
> > sgx_reclaim_pages() scans to be specified by the caller, and adjusted
> > in future patches.
> > 
> > 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 | 25 +++++++++++++++----------
> >  1 file changed, 15 insertions(+), 10 deletions(-)
> > 
> > diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
> > index 83aaf5cea7b9..f201ca85212f 100644
> > --- a/arch/x86/kernel/cpu/sgx/main.c
> > +++ b/arch/x86/kernel/cpu/sgx/main.c
> > @@ -18,6 +18,8 @@
> >  #include "encl.h"
> >  #include "encls.h"
> >  
> > +#define SGX_MAX_NR_TO_RECLAIM	32
> 
> SGX_NR_TO_SCAN_MAX

Would also deserve a descriptive comment.

BR, Jarkko
diff mbox series

Patch

diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 83aaf5cea7b9..f201ca85212f 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -18,6 +18,8 @@ 
 #include "encl.h"
 #include "encls.h"
 
+#define SGX_MAX_NR_TO_RECLAIM	32
+
 struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
 static int sgx_nr_epc_sections;
 static struct task_struct *ksgxd_tsk;
@@ -273,7 +275,10 @@  static void sgx_reclaimer_write(struct sgx_epc_page *epc_page,
 	mutex_unlock(&encl->lock);
 }
 
-/*
+/**
+ * sgx_reclaim_pages() - Reclaim EPC pages from the consumers
+ * @nr_to_scan:		 Number of EPC pages to scan for reclaim
+ *
  * Take a fixed number of pages from the head of the active page pool and
  * reclaim them to the enclave's private shmem files. Skip the pages, which have
  * been accessed since the last scan. Move those pages to the tail of active
@@ -286,9 +291,9 @@  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(void)
+static void __sgx_reclaim_pages(int nr_to_scan)
 {
-	struct sgx_backing backing[SGX_NR_TO_SCAN];
+	struct sgx_backing backing[SGX_MAX_NR_TO_RECLAIM];
 	struct sgx_epc_page *epc_page, *tmp;
 	struct sgx_encl_page *encl_page;
 	pgoff_t page_index;
@@ -297,7 +302,7 @@  static void __sgx_reclaim_pages(void)
 	int i;
 
 	spin_lock(&sgx_global_lru.lock);
-	for (i = 0; i < SGX_NR_TO_SCAN; i++) {
+	for (i = 0; i < nr_to_scan; i++) {
 		epc_page = sgx_epc_peek_reclaimable(&sgx_global_lru);
 		if (!epc_page)
 			break;
@@ -327,7 +332,7 @@  static void __sgx_reclaim_pages(void)
 	list_for_each_entry_safe(epc_page, tmp, &iso, list) {
 		encl_page = epc_page->encl_owner;
 
-		if (!sgx_reclaimer_age(epc_page))
+		if (i == SGX_MAX_NR_TO_RECLAIM || !sgx_reclaimer_age(epc_page))
 			goto skip;
 
 		page_index = PFN_DOWN(encl_page->desc - encl_page->encl->base);
@@ -371,9 +376,9 @@  static void __sgx_reclaim_pages(void)
 	}
 }
 
-static void sgx_reclaim_pages(void)
+static void sgx_reclaim_pages(int nr_to_scan)
 {
-	__sgx_reclaim_pages();
+	__sgx_reclaim_pages(nr_to_scan);
 	cond_resched();
 }
 
@@ -393,7 +398,7 @@  static bool sgx_should_reclaim(unsigned long watermark)
 void sgx_reclaim_direct(void)
 {
 	if (sgx_should_reclaim(SGX_NR_LOW_PAGES))
-		__sgx_reclaim_pages();
+		__sgx_reclaim_pages(SGX_NR_TO_SCAN);
 }
 
 static int ksgxd(void *p)
@@ -419,7 +424,7 @@  static int ksgxd(void *p)
 				     sgx_should_reclaim(SGX_NR_HIGH_PAGES));
 
 		if (sgx_should_reclaim(SGX_NR_HIGH_PAGES))
-			sgx_reclaim_pages();
+			sgx_reclaim_pages(SGX_NR_TO_SCAN);
 	}
 
 	return 0;
@@ -598,7 +603,7 @@  struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim)
 			break;
 		}
 
-		sgx_reclaim_pages();
+		sgx_reclaim_pages(SGX_NR_TO_SCAN);
 	}
 
 	if (sgx_should_reclaim(SGX_NR_LOW_PAGES))