[PATCH RFC 3/9] mm: add methord to charge kmalloc-ed address

Yafang Shao
2022-03-08T13:11:20Z

This patch implements a methord to charge or uncharge related pages
or objects from a given kmalloc-ed address. It is similar to kfree,
except that it doesn't touch the pages or objects while does account
only.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
---
include/linux/slab.h | 1 +
mm/slab.c | 6 ++++++
mm/slob.c | 6 ++++++
mm/slub.c | 32 ++++++++++++++++++++++++++++++++
4 files changed, 45 insertions(+)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index 5b6193f..ae82e23 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -182,6 +182,7 @@ struct kmem_cache *kmem_cache_create_usercopy(const char *name,
void * __must_check krealloc(const void *objp, size_t new_size, gfp_t flags) __alloc_size(2);
void kfree(const void *objp);
void kfree_sensitive(const void *objp);
+void kcharge(const void *objp, bool charge);
size_t __ksize(const void *objp);
size_t ksize(const void *objp);
#ifdef CONFIG_PRINTK
diff --git a/mm/slab.c b/mm/slab.c
index ddf5737..fbff613 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3796,6 +3796,12 @@ void kfree(const void *objp)
}
EXPORT_SYMBOL(kfree);

+void kcharge(const void *objp, bool charge)
+{
+ /* Not implemented yet */
+}
+EXPORT_SYMBOL(kfree);
+
/*
* This initializes kmem_cache_node or resizes various caches for all nodes.
*/
diff --git a/mm/slob.c b/mm/slob.c
index 60c5842..d3a789f 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -569,6 +569,12 @@ void kfree(const void *block)
}
EXPORT_SYMBOL(kfree);

+void kcharge(const void *block, bool charge)
+{
+ /* not implemented yet. */
+}
+EXPORT_SYMBOL(kcharge);
+
/* can't use ksize for kmem_cache_alloc memory, only kmalloc */
size_t __ksize(const void *block)
{
diff --git a/mm/slub.c b/mm/slub.c
index 2614740..e933d45 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4563,6 +4563,38 @@ void kfree(const void *x)
}
EXPORT_SYMBOL(kfree);

+void kcharge(const void *x, bool charge)
+{
+ void *object = (void *)x;
+ struct folio *folio;
+ struct slab *slab;
+
+ WARN_ON(!in_task());
+
+ if (unlikely(ZERO_OR_NULL_PTR(x)))
+ return;
+
+ folio = virt_to_folio(x);
+ if (unlikely(!folio_test_slab(folio))) {
+ unsigned int order = folio_order(folio);
+ int sign = charge ? 1 : -1;
+
+ mod_lruvec_page_state(folio_page(folio, 0), NR_SLAB_UNRECLAIMABLE_B,
+ sign * (PAGE_SIZE << order));
+
+ return;
+ }
+
+ slab = folio_slab(folio);
+ if (charge)
+ memcg_slab_post_alloc_hook(slab->slab_cache,
+ get_obj_cgroup_from_current(), GFP_KERNEL, 1, &object);
+ else
+ memcg_slab_free_hook(slab->slab_cache, &object, 1);
+
+}
+EXPORT_SYMBOL(kcharge);
+
#define SHRINK_PROMOTE_MAX 32

/*
--
1.8.3.1