mm: vmalloc: streamline vmalloc memory accounting

Use a vmstat counter instead of a custom, open-coded atomic. This has
the added benefit of making the data available per-node, and prepares
for cleaning up the memcg accounting as well.

Link: https://lkml.kernel.org/r/20260223160147.3792777-1-hannes@cmpxchg.org
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c
index a458f1e112fdbc63019239a79ce39c5576b5f963..549793f447264240b166d603432fdf13c4127fd4 100644 (file)
--- a/fs/proc/meminfo.c
+++ b/fs/proc/meminfo.c
@@ -126,7 +126,8 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
        show_val_kb(m, "Committed_AS:   ", committed);
        seq_printf(m, "VmallocTotal:   %8lu kB\n",
                   (unsigned long)VMALLOC_TOTAL >> 10);
-       show_val_kb(m, "VmallocUsed:    ", vmalloc_nr_pages());
+       show_val_kb(m, "VmallocUsed:    ",
+                   global_node_page_state(NR_VMALLOC));
        show_val_kb(m, "VmallocChunk:   ", 0ul);
        show_val_kb(m, "Percpu:         ", pcpu_nr_pages());
 

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 546bca95ca40c311a11879f01f6fe520ba7f1cd2..db41b18a919d67c08134e7418023872156b76f51 100644 (file)
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -220,6 +220,7 @@ enum node_stat_item {
        NR_KERNEL_MISC_RECLAIMABLE,     /* reclaimable non-slab kernel pages */
        NR_FOLL_PIN_ACQUIRED,   /* via: pin_user_page(), gup flag: FOLL_PIN */
        NR_FOLL_PIN_RELEASED,   /* pages returned via unpin_user_page() */
+       NR_VMALLOC,
        NR_KERNEL_STACK_KB,     /* measured in KiB */
 #if IS_ENABLED(CONFIG_SHADOW_CALL_STACK)
        NR_KERNEL_SCS_KB,       /* measured in KiB */

diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index e8e94f90d68665d2f53ba09bad0e0a2b312c762a..3b02c0c6b371871b2a62cb733725cc84289d5def 100644 (file)
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -286,8 +286,6 @@ int unregister_vmap_purge_notifier(struct notifier_block *nb);
 #ifdef CONFIG_MMU
 #define VMALLOC_TOTAL (VMALLOC_END - VMALLOC_START)
 
-unsigned long vmalloc_nr_pages(void);
-
 int vm_area_map_pages(struct vm_struct *area, unsigned long start,
                      unsigned long end, struct page **pages);
 void vm_area_unmap_pages(struct vm_struct *area, unsigned long start,
@@ -304,7 +302,6 @@ static inline void set_vm_flush_reset_perms(void *addr)
 #else  /* !CONFIG_MMU */
 #define VMALLOC_TOTAL 0UL
 
-static inline unsigned long vmalloc_nr_pages(void) { return 0; }
 static inline void set_vm_flush_reset_perms(void *addr) {}
 #endif /* CONFIG_MMU */
 

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 61caa55a44027b4f09796b0f21d36430b9b8f2d5..e9d7c2a8c753894de0defc894ebaccf4fe97ef8e 100644 (file)
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1068,14 +1068,8 @@ static BLOCKING_NOTIFIER_HEAD(vmap_notify_list);
 static void drain_vmap_area_work(struct work_struct *work);
 static DECLARE_WORK(drain_vmap_work, drain_vmap_area_work);
 
-static __cacheline_aligned_in_smp atomic_long_t nr_vmalloc_pages;
 static __cacheline_aligned_in_smp atomic_long_t vmap_lazy_nr;
 
-unsigned long vmalloc_nr_pages(void)
-{
-       return atomic_long_read(&nr_vmalloc_pages);
-}
-
 static struct vmap_area *__find_vmap_area(unsigned long addr, struct rb_root *root)
 {
        struct rb_node *n = root->rb_node;
@@ -3476,11 +3470,11 @@ void vfree(const void *addr)
                 * High-order allocs for huge vmallocs are split, so
                 * can be freed as an array of order-0 allocations
                 */
+               if (!(vm->flags & VM_MAP_PUT_PAGES))
+                       dec_node_page_state(page, NR_VMALLOC);
                __free_page(page);
                cond_resched();
        }
-       if (!(vm->flags & VM_MAP_PUT_PAGES))
-               atomic_long_sub(vm->nr_pages, &nr_vmalloc_pages);
        kvfree(vm->pages);
        kfree(vm);
 }
@@ -3668,6 +3662,8 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
                        continue;
                }
 
+               mod_node_page_state(page_pgdat(page), NR_VMALLOC, 1 << large_order);
+
                split_page(page, large_order);
                for (i = 0; i < (1U << large_order); i++)
                        pages[nr_allocated + i] = page + i;
@@ -3688,6 +3684,7 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
        if (!order) {
                while (nr_allocated < nr_pages) {
                        unsigned int nr, nr_pages_request;
+                       int i;
 
                        /*
                         * A maximum allowed request is hard-coded and is 100
@@ -3711,6 +3708,9 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
                                                        nr_pages_request,
                                                        pages + nr_allocated);
 
+                       for (i = nr_allocated; i < nr_allocated + nr; i++)
+                               inc_node_page_state(pages[i], NR_VMALLOC);
+
                        nr_allocated += nr;
 
                        /*
@@ -3735,6 +3735,8 @@ vm_area_alloc_pages(gfp_t gfp, int nid,
                if (unlikely(!page))
                        break;
 
+               mod_node_page_state(page_pgdat(page), NR_VMALLOC, 1 << order);
+
                /*
                 * High-order allocations must be able to be treated as
                 * independent small pages by callers (as they can with
@@ -3877,7 +3879,6 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
                        vmalloc_gfp_adjust(gfp_mask, page_order), node,
                        page_order, nr_small_pages, area->pages);
 
-       atomic_long_add(area->nr_pages, &nr_vmalloc_pages);
        /* All pages of vm should be charged to same memcg, so use first one. */
        if (gfp_mask & __GFP_ACCOUNT && area->nr_pages)
                mod_memcg_page_state(area->pages[0], MEMCG_VMALLOC,

diff --git a/mm/vmstat.c b/mm/vmstat.c
index 667474773dbc7d5ce728028662dcb176578800d8..2370c6fb1fcd6c94983d05495f3b641dde484747 100644 (file)
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1255,6 +1255,7 @@ const char * const vmstat_text[] = {
        [I(NR_KERNEL_MISC_RECLAIMABLE)]         = "nr_kernel_misc_reclaimable",
        [I(NR_FOLL_PIN_ACQUIRED)]               = "nr_foll_pin_acquired",
        [I(NR_FOLL_PIN_RELEASED)]               = "nr_foll_pin_released",
+       [I(NR_VMALLOC)]                         = "nr_vmalloc",
        [I(NR_KERNEL_STACK_KB)]                 = "nr_kernel_stack",
 #if IS_ENABLED(CONFIG_SHADOW_CALL_STACK)
        [I(NR_KERNEL_SCS_KB)]                   = "nr_shadow_call_stack",