Re: [PATCH v12 07/10] secretmem: add memcg accounting

On Sun, Nov 29, 2020 at 07:53:45AM -0800, Shakeel Butt wrote:

On Wed, Nov 25, 2020 at 1:51 AM Mike Rapoport rppt@kernel.org wrote:

...

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

---

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 249cf489f5df..cf7f1dc9f4b8 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 @@ -844,7 +845,7 @@ static 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 52a900a135a5..eb6628390444 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_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE_B,
  

•                       PAGE_SIZE << order);
  

Please use mod_lruvec_page_state() instead, so we get the memcg stats too.

Ok

BTW I think secretmem deserves a vmstat entry instead of overloading NR_SLAB_UNRECLAIMABLE_B.

I'd prefer to wait with a dedicated vmstat for now. We can always add it later, once we have better picture of secremem usage.

...

•   return 0;
  

+}

+static void secretmem_unaccount_pages(struct page *page, int order) +{

•   mod_node_page_state(page_pgdat(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); @@ -56,10 +83,14 @@ 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_account_pages(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)
  

@@ -76,6 +107,8 @@ 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; @@ -302,6 +335,7 @@ 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