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mm: swap_cgroup: allocate swap_cgroup map using vcalloc()

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Currently swap_cgroup's map is constructed as a vmalloc()'s-based array of
pointers to individual struct pages.  This brings an unnecessary
complexity into the code.

This patch turns the swap_cgroup's map into a single space
allocated by vcalloc().

[akpm@linux-foundation.org: s/vfree/kvfree/, per Shakeel]
Link: https://lkml.kernel.org/r/20241115190229.676440-1-roman.gushchin@linux.dev
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Roman Gushchin
2024-11-15 19:02:28 +00:00
committed by Andrew Morton
parent 3472f639c6
commit 8eb92ed254
1 changed files with 13 additions and 70 deletions
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83
mm/swap_cgroup.c
View File

@@ -6,17 +6,18 @@
#include <linux/swapops.h> /* depends on mm.h include */
static DEFINE_MUTEX(swap_cgroup_mutex);
struct swap_cgroup {
unsigned short id;
};
struct swap_cgroup_ctrl {
struct page **map;
unsigned long length;
struct swap_cgroup *map;
spinlock_t lock;
};
static struct swap_cgroup_ctrl swap_cgroup_ctrl[MAX_SWAPFILES];
struct swap_cgroup {
unsigned short id;
};
#define SC_PER_PAGE (PAGE_SIZE/sizeof(struct swap_cgroup))
/*
@@ -33,44 +34,10 @@ struct swap_cgroup {
* TODO: we can push these buffers out to HIGHMEM.
*/
/*
* allocate buffer for swap_cgroup.
*/
static int swap_cgroup_prepare(int type)
{
struct page *page;
struct swap_cgroup_ctrl *ctrl;
unsigned long idx, max;
ctrl = &swap_cgroup_ctrl[type];
for (idx = 0; idx < ctrl->length; idx++) {
page = alloc_page(GFP_KERNEL | __GFP_ZERO);
if (!page)
goto not_enough_page;
ctrl->map[idx] = page;
if (!(idx % SWAP_CLUSTER_MAX))
cond_resched();
}
return 0;
not_enough_page:
max = idx;
for (idx = 0; idx < max; idx++)
__free_page(ctrl->map[idx]);
return -ENOMEM;
}
static struct swap_cgroup *__lookup_swap_cgroup(struct swap_cgroup_ctrl *ctrl,
pgoff_t offset)
{
struct page *mappage;
struct swap_cgroup *sc;
mappage = ctrl->map[offset / SC_PER_PAGE];
sc = page_address(mappage);
return sc + offset % SC_PER_PAGE;
return &ctrl->map[offset];
}
static struct swap_cgroup *lookup_swap_cgroup(swp_entry_t ent,
@@ -168,32 +135,20 @@ unsigned short lookup_swap_cgroup_id(swp_entry_t ent)
int swap_cgroup_swapon(int type, unsigned long max_pages)
{
void *array;
unsigned long length;
struct swap_cgroup *map;
struct swap_cgroup_ctrl *ctrl;
if (mem_cgroup_disabled())
return 0;
length = DIV_ROUND_UP(max_pages, SC_PER_PAGE);
array = vcalloc(length, sizeof(void *));
if (!array)
map = vcalloc(max_pages, sizeof(struct swap_cgroup));
if (!map)
goto nomem;
ctrl = &swap_cgroup_ctrl[type];
mutex_lock(&swap_cgroup_mutex);
ctrl->length = length;
ctrl->map = array;
ctrl->map = map;
spin_lock_init(&ctrl->lock);
if (swap_cgroup_prepare(type)) {
/* memory shortage */
ctrl->map = NULL;
ctrl->length = 0;
mutex_unlock(&swap_cgroup_mutex);
vfree(array);
goto nomem;
}
mutex_unlock(&swap_cgroup_mutex);
return 0;
@@ -205,8 +160,7 @@ nomem:
void swap_cgroup_swapoff(int type)
{
struct page **map;
unsigned long i, length;
struct swap_cgroup *map;
struct swap_cgroup_ctrl *ctrl;
if (mem_cgroup_disabled())
@@ -215,19 +169,8 @@ void swap_cgroup_swapoff(int type)
mutex_lock(&swap_cgroup_mutex);
ctrl = &swap_cgroup_ctrl[type];
map = ctrl->map;
length = ctrl->length;
ctrl->map = NULL;
ctrl->length = 0;
mutex_unlock(&swap_cgroup_mutex);
if (map) {
for (i = 0; i < length; i++) {
struct page *page = map[i];
if (page)
__free_page(page);
if (!(i % SWAP_CLUSTER_MAX))
cond_resched();
}
vfree(map);
}
vfree(map);
}