[PATCH v16 08/11] secretmem: add memcg accounting

Mike Rapoport
2021-01-21T12:30:34Z

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>
Acked-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christopher Lameter <cl@linux.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Hagen Paul Pfeifer <hagen@jauu.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tycho Andersen <tycho@tycho.ws>
Cc: Will Deacon <will@kernel.org>
---
mm/filemap.c | 3 ++-
mm/secretmem.c | 36 +++++++++++++++++++++++++++++++++++-
2 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index 2d0c6721879d..bb28dd6d9e22 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -42,6 +42,7 @@
#include <linux/psi.h>
#include <linux/ramfs.h>
#include <linux/page_idle.h>
+#include <linux/secretmem.h>
#include "internal.h"

#define CREATE_TRACE_POINTS
@@ -839,7 +840,7 @@ noinline int __add_to_page_cache_locked(struct page *page,
page->mapping = mapping;
page->index = offset;

- if (!huge) {
+ if (!huge && !page_is_secretmem(page)) {
error = mem_cgroup_charge(page, current->mm, gfp);
if (error)
goto error;
diff --git a/mm/secretmem.c b/mm/secretmem.c
index 469211c7cc3a..05026460e2ee 100644
--- a/mm/secretmem.c
+++ b/mm/secretmem.c
@@ -18,6 +18,7 @@
#include <linux/memblock.h>
#include <linux/pseudo_fs.h>
#include <linux/secretmem.h>
+#include <linux/memcontrol.h>
#include <linux/set_memory.h>
#include <linux/sched/signal.h>

@@ -44,6 +45,32 @@ struct secretmem_ctx {

static struct cma *secretmem_cma;

+static int secretmem_account_pages(struct page *page, gfp_t gfp, int order)
+{
+ int err;
+
+ err = memcg_kmem_charge_page(page, gfp, order);
+ if (err)
+ return err;
+
+ /*
+ * seceremem caches are unreclaimable kernel allocations, so treat
+ * them as unreclaimable slab memory for VM statistics purposes
+ */
+ mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B,
+ PAGE_SIZE << order);
+
+ return 0;
+}
+
+static void secretmem_unaccount_pages(struct page *page, int order)
+{
+
+ mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B,
+ -PAGE_SIZE << order);
+ memcg_kmem_uncharge_page(page, order);
+}
+
static int secretmem_pool_increase(struct secretmem_ctx *ctx, gfp_t gfp)
{
unsigned long nr_pages = (1 << PMD_PAGE_ORDER);
@@ -56,6 +83,10 @@ static int secretmem_pool_increase(struct secretmem_ctx *ctx, gfp_t gfp)
if (!page)
return -ENOMEM;

+ err = secretmem_account_pages(page, gfp, PMD_PAGE_ORDER);
+ if (err)
+ goto err_cma_release;
+
/*
* clear the data left from the prevoius user before dropping the
* pages from the direct map
@@ -65,7 +96,7 @@ static int secretmem_pool_increase(struct secretmem_ctx *ctx, gfp_t gfp)

err = set_direct_map_invalid_noflush(page, nr_pages);
if (err)
- goto err_cma_release;
+ goto err_memcg_uncharge;

addr = (unsigned long)page_address(page);
err = gen_pool_add(pool, addr, PMD_SIZE, NUMA_NO_NODE);
@@ -83,6 +114,8 @@ 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_unaccount_pages(page, PMD_PAGE_ORDER);
err_cma_release:
cma_release(secretmem_cma, page, nr_pages);
return err;
@@ -314,6 +347,7 @@ static void secretmem_cleanup_chunk(struct gen_pool *pool,
int i;

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

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