From: Kristen Carlson Accardi <kristen@xxxxxxxxxxxxxxx>
Previous patches have implemented all infrastructure needed for
per-cgroup EPC page tracking and reclaiming. But all reclaimable EPC
pages are still tracked in the global LRU as sgx_epc_page_lru() always
returns reference to the global LRU.
Change sgx_epc_page_lru() to return the LRU of the cgroup in which the
given EPC page is allocated.
Update sgx_can_reclaim_global(), to check emptiness of LRUs of all
cgroups, and update sgx_reclaim_pages_global(), to utilize
sgx_cgroup_reclaim_pages_global(), when EPC cgroup is enabled.
With these changes, the global reclamation and per-cgroup reclamation
both work properly with all pages tracked in per-cgroup LRUs.
Co-developed-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Signed-off-by: Kristen Carlson Accardi <kristen@xxxxxxxxxxxxxxx>
Co-developed-by: Haitao Huang <haitao.huang@xxxxxxxxxxxxxxx>
Signed-off-by: Haitao Huang <haitao.huang@xxxxxxxxxxxxxxx>
Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
---
V16:
- Separated out the global and direct reclamation to earlier patch.(Kai)
V14:
- Update global reclamation to use the new sgx_cgroup_reclaim_pages() to
iterate cgroups at lower level if the top cgroups are too busy.
V13:
- Use IS_ENABLED(CONFIG_CGROUP_MISC) in sgx_can_reclaim_global(). (Kai)
V12:
- Remove CONFIG_CGROUP_SGX_EPC, conditional compile SGX Cgroup for
CONFIGCONFIG_CGROUPMISC. (Jarkko)
V11:
- Reword the comments for global reclamation for allocation failure
after passing cgroup charging. (Kai)
- Add stub functions to remove ifdefs in c file (Kai)
- Add more detailed comments to clarify each page belongs to one cgroup, or the
root. (Kai)
V10:
- Add comment to clarify each page belongs to one cgroup, or the root by
default. (Kai)
- Merge the changes that expose sgx_cgroup_* functions to this patch.
- Add changes for sgx_reclaim_direct() that was missed previously.
V7:
- Split this out from the big patch, #10 in V6. (Dave, Kai)
---
arch/x86/kernel/cpu/sgx/epc_cgroup.c | 2 +-
arch/x86/kernel/cpu/sgx/epc_cgroup.h | 6 ++++
arch/x86/kernel/cpu/sgx/main.c | 45 ++++++++++++++++++----------
3 files changed, 36 insertions(+), 17 deletions(-)
diff --git a/arch/x86/kernel/cpu/sgx/epc_cgroup.c b/arch/x86/kernel/cpu/sgx/epc_cgroup.c
index b7d60b2d878d..c3f0c7bc13c6 100644
--- a/arch/x86/kernel/cpu/sgx/epc_cgroup.c
+++ b/arch/x86/kernel/cpu/sgx/epc_cgroup.c
@@ -162,7 +162,7 @@ static inline u64 sgx_cgroup_max_pages_to_root(struct sgx_cgroup *sgx_cg)
*
* Return: %true if all cgroups under the specified root have empty LRU lists.
*/
-static bool sgx_cgroup_lru_empty(struct misc_cg *root)
+bool sgx_cgroup_lru_empty(struct misc_cg *root)
{
struct cgroup_subsys_state *css_root;
struct cgroup_subsys_state *pos;
diff --git a/arch/x86/kernel/cpu/sgx/epc_cgroup.h b/arch/x86/kernel/cpu/sgx/epc_cgroup.h
index cf2b946d993e..cd957cf38204 100644
--- a/arch/x86/kernel/cpu/sgx/epc_cgroup.h
+++ b/arch/x86/kernel/cpu/sgx/epc_cgroup.h
@@ -27,6 +27,11 @@ static inline int sgx_cgroup_try_charge(struct sgx_cgroup *sgx_cg, enum sgx_recl
static inline void sgx_cgroup_uncharge(struct sgx_cgroup *sgx_cg) { }
+static inline bool sgx_cgroup_lru_empty(struct misc_cg *root)
+{
+ return true;
+}
+
static inline int __init sgx_cgroup_init(void)
{
return 0;
@@ -91,6 +96,7 @@ static inline void sgx_put_cg(struct sgx_cgroup *sgx_cg)
int sgx_cgroup_try_charge(struct sgx_cgroup *sgx_cg, enum sgx_reclaim reclaim);
void sgx_cgroup_uncharge(struct sgx_cgroup *sgx_cg);
+bool sgx_cgroup_lru_empty(struct misc_cg *root);
void sgx_cgroup_reclaim_pages_global(struct mm_struct *charge_mm);
void sgx_cgroup_reclaim_direct(void);
int __init sgx_cgroup_init(void);
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 9a8f91ebd21b..2a23a10d882e 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -32,9 +32,30 @@ static DEFINE_XARRAY(sgx_epc_address_space);
*/
static struct sgx_epc_lru_list sgx_global_lru;
+/*
+ * Get the per-cgroup or global LRU list that tracks the given reclaimable page.
+ */
static inline struct sgx_epc_lru_list *sgx_epc_page_lru(struct sgx_epc_page *epc_page)
{
+#ifdef CONFIG_CGROUP_MISC
+ /*
+ * epc_page->sgx_cg here is never NULL during a reclaimable epc_page's
+ * life between sgx_alloc_epc_page() and sgx_free_epc_page():
+ *
+ * In sgx_alloc_epc_page(), epc_page->sgx_cg is set to the return from
+ * sgx_get_current_cg() which is the misc cgroup of the current task, or
+ * the root by default even if the misc cgroup is disabled by kernel
+ * command line.
+ *
+ * epc_page->sgx_cg is only unset by sgx_free_epc_page().
+ *
+ * This function is never used before sgx_alloc_epc_page() or after
+ * sgx_free_epc_page().
+ */
+ return &epc_page->sgx_cg->lru;
+#else
return &sgx_global_lru;
+#endif
}
/*
@@ -42,14 +63,10 @@ static inline struct sgx_epc_lru_list *sgx_epc_page_lru(struct sgx_epc_page *epc
*/
static inline bool sgx_can_reclaim_global(void)
{
- /*
- * Now all EPC pages are still tracked in the @sgx_global_lru, so only
- * check @sgx_global_lru.
- *
- * When EPC pages are tracked in the actual per-cgroup LRUs,
- * replace with sgx_cgroup_lru_empty(misc_cg_root()).
- */
- return !list_empty(&sgx_global_lru.reclaimable);
+ if (IS_ENABLED(CONFIG_CGROUP_MISC))
+ return !sgx_cgroup_lru_empty(misc_cg_root());
+ else
+ return !list_empty(&sgx_global_lru.reclaimable);
}
static atomic_long_t sgx_nr_free_pages = ATOMIC_LONG_INIT(0);
@@ -411,14 +428,10 @@ static bool sgx_should_reclaim_global(unsigned long watermark)
static void sgx_reclaim_pages_global(struct mm_struct *charge_mm)
{
- /*
- * Now all EPC pages are still tracked in the @sgx_global_lru.
- * Still reclaim from it.
- *
- * When EPC pages are tracked in the actual per-cgroup LRUs,
- * sgx_cgroup_reclaim_pages_global() will be called.
- */
- sgx_reclaim_pages(&sgx_global_lru, charge_mm);
+ if (IS_ENABLED(CONFIG_CGROUP_MISC))
+ sgx_cgroup_reclaim_pages_global(charge_mm);
+ else
+ sgx_reclaim_pages(&sgx_global_lru, charge_mm);
}
/*
--
2.43.0
