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Message-Id: <20221202183655.3767674-14-kristen@linux.intel.com>
Date: Fri, 2 Dec 2022 10:36:49 -0800
From: Kristen Carlson Accardi <kristen@...ux.intel.com>
To: jarkko@...nel.org, dave.hansen@...ux.intel.com, tj@...nel.org,
linux-kernel@...r.kernel.org, linux-sgx@...r.kernel.org,
cgroups@...r.kernel.org, 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: zhiquan1.li@...el.com,
Kristen Carlson Accardi <kristen@...ux.intel.com>,
Sean Christopherson <seanjc@...gle.com>
Subject: [PATCH v2 13/18] x86/sgx: Add helper to grab pages from an arbitrary EPC LRU
From: Sean Christopherson <sean.j.christopherson@...el.com>
Move the isolation loop into a standalone helper, sgx_isolate_pages(),
in preparation for existence of multiple LRUs. Expose the helper to
other SGX code so that it can be called from the EPC cgroup code, e.g.
to isolate pages from a single cgroup LRU. Exposing the isolation loop
allows the cgroup iteration logic to be wholly encapsulated within the
cgroup code.
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 | 68 +++++++++++++++++++++-------------
arch/x86/kernel/cpu/sgx/sgx.h | 2 +
2 files changed, 44 insertions(+), 26 deletions(-)
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index c947b4ae06f3..a59550fa150b 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -280,7 +280,46 @@ static void sgx_reclaimer_write(struct sgx_epc_page *epc_page,
}
/**
- * sgx_reclaim_pages() - Reclaim EPC pages from the consumers
+ * sgx_isolate_epc_pages() - Isolate pages from an LRU for reclaim
+ * @lru: LRU from which to reclaim
+ * @nr_to_scan: Number of pages to scan for reclaim
+ * @dst: Destination list to hold the isolated pages
+ */
+void sgx_isolate_epc_pages(struct sgx_epc_lru_lists *lru, int *nr_to_scan,
+ struct list_head *dst)
+{
+ struct sgx_encl_page *encl_page;
+ struct sgx_epc_page *epc_page;
+
+ spin_lock(&lru->lock);
+ for (; *nr_to_scan > 0; --(*nr_to_scan)) {
+ if (list_empty(&lru->reclaimable))
+ break;
+
+ epc_page = sgx_epc_peek_reclaimable(lru);
+ if (!epc_page)
+ break;
+
+ encl_page = epc_page->encl_owner;
+
+ if (WARN_ON_ONCE(!(epc_page->flags & SGX_EPC_PAGE_ENCLAVE)))
+ continue;
+
+ if (kref_get_unless_zero(&encl_page->encl->refcount)) {
+ epc_page->flags |= SGX_EPC_PAGE_RECLAIM_IN_PROGRESS;
+ list_move_tail(&epc_page->list, dst);
+ } else {
+ /* The owner is freeing the page, remove it from the
+ * LRU list
+ */
+ epc_page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;
+ list_del_init(&epc_page->list);
+ }
+ }
+ spin_unlock(&lru->lock);
+}
+
+/**
* sgx_reclaim_epc_pages() - Reclaim EPC pages from the consumers
* @nr_to_scan: Number of EPC pages to scan for reclaim
* @ignore_age: Reclaim a page even if it is young
@@ -305,37 +344,14 @@ static int __sgx_reclaim_pages(int nr_to_scan, bool ignore_age)
struct sgx_epc_lru_lists *lru;
pgoff_t page_index;
LIST_HEAD(iso);
+ int i = 0;
int ret;
- int i;
-
- spin_lock(&sgx_global_lru.lock);
- for (i = 0; i < nr_to_scan; i++) {
- epc_page = sgx_epc_peek_reclaimable(&sgx_global_lru);
- if (!epc_page)
- break;
-
- encl_page = epc_page->encl_owner;
- if (WARN_ON_ONCE(!(epc_page->flags & SGX_EPC_PAGE_ENCLAVE)))
- continue;
-
- if (kref_get_unless_zero(&encl_page->encl->refcount) != 0) {
- epc_page->flags |= SGX_EPC_PAGE_RECLAIM_IN_PROGRESS;
- list_move_tail(&epc_page->list, &iso);
- } else {
- /* The owner is freeing the page, remove it from the
- * LRU list
- */
- epc_page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;
- list_del_init(&epc_page->list);
- }
- }
- spin_unlock(&sgx_global_lru.lock);
+ sgx_isolate_epc_pages(&sgx_global_lru, &nr_to_scan, &iso);
if (list_empty(&iso))
return 0;
- i = 0;
list_for_each_entry_safe(epc_page, tmp, &iso, list) {
encl_page = epc_page->encl_owner;
diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h
index ce859331ddf5..4499a5d5547d 100644
--- a/arch/x86/kernel/cpu/sgx/sgx.h
+++ b/arch/x86/kernel/cpu/sgx/sgx.h
@@ -207,6 +207,8 @@ void sgx_record_epc_page(struct sgx_epc_page *page, unsigned long flags);
int sgx_drop_epc_page(struct sgx_epc_page *page);
struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim);
int sgx_reclaim_epc_pages(int nr_to_scan, bool ignore_age);
+void sgx_isolate_epc_pages(struct sgx_epc_lru_lists *lrus, int *nr_to_scan,
+ struct list_head *dst);
void sgx_ipi_cb(void *info);
--
2.38.1
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