[PATCH v8 6/9] secretmem: add memcg accounting

Mike Rapoport
2020-11-10T15:16:06Z

From: Mike Rapoport <rppt@linux.ibm.com>

Account memory consumed by secretmem to memcg. The accounting is updated
when the memory is actually allocated and freed.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
---
mm/filemap.c | 2 +-
mm/secretmem.c | 42 +++++++++++++++++++++++++++++++++++++++++-
2 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index 249cf489f5df..11387a077373 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -844,7 +844,7 @@ static noinline int __add_to_page_cache_locked(struct page *page,
page->mapping = mapping;
page->index = offset;

- if (!huge) {
+ if (!huge && !page->memcg_data) {
error = mem_cgroup_charge(page, current->mm, gfp);
if (error)
goto error;
diff --git a/mm/secretmem.c b/mm/secretmem.c
index 1aa2b7cffe0d..1eb7667016fa 100644
--- a/mm/secretmem.c
+++ b/mm/secretmem.c
@@ -17,6 +17,7 @@
#include <linux/syscalls.h>
#include <linux/memblock.h>
#include <linux/pseudo_fs.h>
+#include <linux/memcontrol.h>
#include <linux/set_memory.h>
#include <linux/sched/signal.h>

@@ -49,6 +50,38 @@ struct secretmem_ctx {

static struct cma *secretmem_cma;

+static int secretmem_memcg_charge(struct page *page, gfp_t gfp, int order)
+{
+ unsigned long nr_pages = (1 << order);
+ int i, err;
+
+ err = memcg_kmem_charge_page(page, gfp, order);
+ if (err)
+ return err;
+
+ for (i = 1; i < nr_pages; i++) {
+ struct page *p = page + i;
+
+ p->memcg_data = page->memcg_data;
+ }
+
+ return 0;
+}
+
+static void secretmem_memcg_uncharge(struct page *page, int order)
+{
+ unsigned long nr_pages = (1 << order);
+ int i;
+
+ for (i = 1; i < nr_pages; i++) {
+ struct page *p = page + i;
+
+ p->memcg_data = 0;
+ }
+
+ memcg_kmem_uncharge_page(page, PMD_PAGE_ORDER);
+}
+
static int secretmem_pool_increase(struct secretmem_ctx *ctx, gfp_t gfp)
{
unsigned long nr_pages = (1 << PMD_PAGE_ORDER);
@@ -61,10 +94,14 @@ static int secretmem_pool_increase(struct secretmem_ctx *ctx, gfp_t gfp)
if (!page)
return -ENOMEM;

- err = set_direct_map_invalid_noflush(page, nr_pages);
+ err = secretmem_memcg_charge(page, gfp, PMD_PAGE_ORDER);
if (err)
goto err_cma_release;

+ err = set_direct_map_invalid_noflush(page, nr_pages);
+ if (err)
+ goto err_memcg_uncharge;
+
addr = (unsigned long)page_address(page);
err = gen_pool_add(pool, addr, PMD_SIZE, NUMA_NO_NODE);
if (err)
@@ -81,6 +118,8 @@ static int secretmem_pool_increase(struct secretmem_ctx *ctx, gfp_t gfp)
* won't fail
*/
set_direct_map_default_noflush(page, nr_pages);
+err_memcg_uncharge:
+ secretmem_memcg_uncharge(page, PMD_PAGE_ORDER);
err_cma_release:
cma_release(secretmem_cma, page, nr_pages);
return err;
@@ -310,6 +349,7 @@ static void secretmem_cleanup_chunk(struct gen_pool *pool,
int i;

set_direct_map_default_noflush(page, nr_pages);
+ secretmem_memcg_uncharge(page, PMD_PAGE_ORDER);

for (i = 0; i < nr_pages; i++)
clear_highpage(page + i);
--
2.28.0