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Message-Id: <20240328002229.30264-13-haitao.huang@linux.intel.com>
Date: Wed, 27 Mar 2024 17:22:27 -0700
From: Haitao Huang <haitao.huang@...ux.intel.com>
To: jarkko@...nel.org,
dave.hansen@...ux.intel.com,
kai.huang@...el.com,
tj@...nel.org,
mkoutny@...e.com,
linux-kernel@...r.kernel.org,
linux-sgx@...r.kernel.org,
x86@...nel.org,
cgroups@...r.kernel.org,
tglx@...utronix.de,
mingo@...hat.com,
bp@...en8.de,
hpa@...or.com,
sohil.mehta@...el.com,
tim.c.chen@...ux.intel.com
Cc: zhiquan1.li@...el.com,
kristen@...ux.intel.com,
seanjc@...gle.com,
zhanb@...rosoft.com,
anakrish@...rosoft.com,
mikko.ylinen@...ux.intel.com,
yangjie@...rosoft.com,
chrisyan@...rosoft.com
Subject: [PATCH v10 12/14] x86/sgx: Turn on per-cgroup EPC reclamation
From: Kristen Carlson Accardi <kristen@...ux.intel.com>
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_lru_list() returns hard
coded reference to the global LRU.
Change sgx_lru_list() to return the LRU of the cgroup in which the given
EPC page is allocated.
This makes all EPC pages tracked in per-cgroup LRUs and the global
reclaimer (ksgxd) will not be able to reclaim any pages from the global
LRU. However, in cases of over-committing, i.e., the sum of cgroup
limits greater than the total capacity, cgroups may never reclaim but
the total usage can still be near the capacity. Therefore a global
reclamation is still needed in those cases and it should be performed
from the root cgroup.
Modify sgx_reclaim_pages_global(), to reclaim from the root EPC cgroup
when cgroup is enabled, otherwise from the global LRU. Export
sgx_cgroup_reclaim_pages() in the header file so it can be reused for
this purpose.
Similarly, modify sgx_can_reclaim(), to check emptiness of LRUs of all
cgroups when EPC cgroup is enabled, otherwise only check the global LRU.
Export sgx_cgroup_lru_empty() so it can be reused for this purpose.
Finally, change sgx_reclaim_direct(), to check and ensure there are free
pages at cgroup level so forward progress can be made by the caller.
Export sgx_cgroup_should_reclaim() for reuse.
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@...el.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
Signed-off-by: Kristen Carlson Accardi <kristen@...ux.intel.com>
Co-developed-by: Haitao Huang <haitao.huang@...ux.intel.com>
Signed-off-by: Haitao Huang <haitao.huang@...ux.intel.com>
---
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 | 6 +++---
arch/x86/kernel/cpu/sgx/epc_cgroup.h | 7 +++++++
arch/x86/kernel/cpu/sgx/main.c | 29 +++++++++++++++++++++++++++-
3 files changed, 38 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/cpu/sgx/epc_cgroup.c b/arch/x86/kernel/cpu/sgx/epc_cgroup.c
index 1defbf213e8d..cacd9e93344e 100644
--- a/arch/x86/kernel/cpu/sgx/epc_cgroup.c
+++ b/arch/x86/kernel/cpu/sgx/epc_cgroup.c
@@ -72,7 +72,7 @@ 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;
@@ -125,7 +125,7 @@ static bool sgx_cgroup_lru_empty(struct misc_cg *root)
* triggering reclamation, and call cond_resched() in between iterations to
* avoid indefinite blocking.
*/
-static void sgx_cgroup_reclaim_pages(struct misc_cg *root, struct mm_struct *charge_mm)
+void sgx_cgroup_reclaim_pages(struct misc_cg *root, struct mm_struct *charge_mm)
{
struct cgroup_subsys_state *css_root;
struct cgroup_subsys_state *pos;
@@ -166,7 +166,7 @@ static void sgx_cgroup_reclaim_pages(struct misc_cg *root, struct mm_struct *cha
* threshold (%SGX_CG_MIN_FREE_PAGE) and there are reclaimable pages within the
* cgroup.
*/
-static bool sgx_cgroup_should_reclaim(struct sgx_cgroup *sgx_cg)
+bool sgx_cgroup_should_reclaim(struct sgx_cgroup *sgx_cg)
{
u64 cur, max;
diff --git a/arch/x86/kernel/cpu/sgx/epc_cgroup.h b/arch/x86/kernel/cpu/sgx/epc_cgroup.h
index f66570d3ef42..8f55b38157da 100644
--- a/arch/x86/kernel/cpu/sgx/epc_cgroup.h
+++ b/arch/x86/kernel/cpu/sgx/epc_cgroup.h
@@ -28,6 +28,10 @@ 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 void sgx_cgroup_init(void) { }
+
+static inline void sgx_cgroup_reclaim_pages(struct misc_cg *root, struct mm_struct *charge_mm)
+{
+}
#else
struct sgx_cgroup {
struct misc_cg *cg;
@@ -65,6 +69,9 @@ 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);
+bool sgx_cgroup_should_reclaim(struct sgx_cgroup *sgx_cg);
+void sgx_cgroup_reclaim_pages(struct misc_cg *root, struct mm_struct *charge_mm);
void sgx_cgroup_init(void);
#endif
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 7f92455d957d..68f28ff2d5ef 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -34,6 +34,16 @@ static struct sgx_epc_lru_list sgx_global_lru;
static inline struct sgx_epc_lru_list *sgx_lru_list(struct sgx_epc_page *epc_page)
{
+#ifdef CONFIG_CGROUP_SGX_EPC
+ if (epc_page->sgx_cg)
+ return &epc_page->sgx_cg->lru;
+
+ /*
+ * This should not happen when cgroup is enabled: Every page belongs
+ * to a cgroup, or the root by default.
+ */
+ WARN_ON_ONCE(1);
+#endif
return &sgx_global_lru;
}
@@ -42,7 +52,11 @@ static inline struct sgx_epc_lru_list *sgx_lru_list(struct sgx_epc_page *epc_pag
*/
static inline bool sgx_can_reclaim(void)
{
+#ifdef CONFIG_CGROUP_SGX_EPC
+ return !sgx_cgroup_lru_empty(misc_cg_root());
+#else
return !list_empty(&sgx_global_lru.reclaimable);
+#endif
}
static atomic_long_t sgx_nr_free_pages = ATOMIC_LONG_INIT(0);
@@ -404,7 +418,10 @@ static bool sgx_should_reclaim(unsigned long watermark)
static void sgx_reclaim_pages_global(struct mm_struct *charge_mm)
{
- sgx_reclaim_pages(&sgx_global_lru, charge_mm);
+ if (IS_ENABLED(CONFIG_CGROUP_SGX_EPC))
+ sgx_cgroup_reclaim_pages(misc_cg_root(), charge_mm);
+ else
+ sgx_reclaim_pages(&sgx_global_lru, charge_mm);
}
/*
@@ -414,6 +431,16 @@ static void sgx_reclaim_pages_global(struct mm_struct *charge_mm)
*/
void sgx_reclaim_direct(void)
{
+#ifdef CONFIG_CGROUP_SGX_EPC
+ struct sgx_cgroup *sgx_cg = sgx_get_current_cg();
+
+ /* Make sure there are some free pages at cgroup level */
+ if (sgx_cg && sgx_cgroup_should_reclaim(sgx_cg)) {
+ sgx_cgroup_reclaim_pages(sgx_cg->cg, current->mm);
+ sgx_put_cg(sgx_cg);
+ }
+#endif
+ /* Make sure there are some free pages at global level */
if (sgx_should_reclaim(SGX_NR_LOW_PAGES))
sgx_reclaim_pages_global(current->mm);
}
--
2.25.1
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