@@ -735,17 +735,6 @@ struct vm_area_struct {
*/
unsigned int vm_lock_seq;
#endif
-
- /*
- * For areas with an address space and backing store,
- * linkage into the address_space->i_mmap interval tree.
- *
- */
- struct {
- struct rb_node rb;
- unsigned long rb_subtree_last;
- } shared;
-
/*
* A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
* list, after a COW of one of the file pages. A MAP_SHARED vma
@@ -765,14 +754,6 @@ struct vm_area_struct {
struct file * vm_file; /* File we map to (can be NULL). */
void * vm_private_data; /* was vm_pte (shared mem) */
-#ifdef CONFIG_ANON_VMA_NAME
- /*
- * For private and shared anonymous mappings, a pointer to a null
- * terminated string containing the name given to the vma, or NULL if
- * unnamed. Serialized by mmap_lock. Use anon_vma_name to access.
- */
- struct anon_vma_name *anon_name;
-#endif
#ifdef CONFIG_SWAP
atomic_long_t swap_readahead_info;
#endif
@@ -785,7 +766,6 @@ struct vm_area_struct {
#ifdef CONFIG_NUMA_BALANCING
struct vma_numab_state *numab_state; /* NUMA Balancing state */
#endif
- struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
#ifdef CONFIG_PER_VMA_LOCK
/* Unstable RCU readers are allowed to read this. */
refcount_t vm_refcnt ____cacheline_aligned_in_smp;
@@ -793,6 +773,24 @@ struct vm_area_struct {
struct lockdep_map vmlock_dep_map;
#endif
#endif
+ /*
+ * For areas with an address space and backing store,
+ * linkage into the address_space->i_mmap interval tree.
+ *
+ */
+ struct {
+ struct rb_node rb;
+ unsigned long rb_subtree_last;
+ } shared;
+#ifdef CONFIG_ANON_VMA_NAME
+ /*
+ * For private and shared anonymous mappings, a pointer to a null
+ * terminated string containing the name given to the vma, or NULL if
+ * unnamed. Serialized by mmap_lock. Use anon_vma_name to access.
+ */
+ struct anon_vma_name *anon_name;
+#endif
+ struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
} __randomize_layout;
#ifdef CONFIG_NUMA
@@ -279,16 +279,6 @@ struct vm_area_struct {
unsigned int vm_lock_seq;
#endif
- /*
- * For areas with an address space and backing store,
- * linkage into the address_space->i_mmap interval tree.
- *
- */
- struct {
- struct rb_node rb;
- unsigned long rb_subtree_last;
- } shared;
-
/*
* A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
* list, after a COW of one of the file pages. A MAP_SHARED vma
@@ -308,14 +298,6 @@ struct vm_area_struct {
struct file * vm_file; /* File we map to (can be NULL). */
void * vm_private_data; /* was vm_pte (shared mem) */
-#ifdef CONFIG_ANON_VMA_NAME
- /*
- * For private and shared anonymous mappings, a pointer to a null
- * terminated string containing the name given to the vma, or NULL if
- * unnamed. Serialized by mmap_lock. Use anon_vma_name to access.
- */
- struct anon_vma_name *anon_name;
-#endif
#ifdef CONFIG_SWAP
atomic_long_t swap_readahead_info;
#endif
@@ -328,11 +310,28 @@ struct vm_area_struct {
#ifdef CONFIG_NUMA_BALANCING
struct vma_numab_state *numab_state; /* NUMA Balancing state */
#endif
- struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
#ifdef CONFIG_PER_VMA_LOCK
/* Unstable RCU readers are allowed to read this. */
refcount_t vm_refcnt;
#endif
+ /*
+ * For areas with an address space and backing store,
+ * linkage into the address_space->i_mmap interval tree.
+ *
+ */
+ struct {
+ struct rb_node rb;
+ unsigned long rb_subtree_last;
+ } shared;
+#ifdef CONFIG_ANON_VMA_NAME
+ /*
+ * For private and shared anonymous mappings, a pointer to a null
+ * terminated string containing the name given to the vma, or NULL if
+ * unnamed. Serialized by mmap_lock. Use anon_vma_name to access.
+ */
+ struct anon_vma_name *anon_name;
+#endif
+ struct vm_userfaultfd_ctx vm_userfaultfd_ctx;
} __randomize_layout;
struct vm_fault {};
Move several vma_area_struct members which are rarely or never used during page fault handling into the last cacheline to better pack vm_area_struct. As a result vm_area_struct will fit into 3 as opposed to 4 cachelines. New typical vm_area_struct layout: struct vm_area_struct { union { struct { long unsigned int vm_start; /* 0 8 */ long unsigned int vm_end; /* 8 8 */ }; /* 0 16 */ freeptr_t vm_freeptr; /* 0 8 */ }; /* 0 16 */ struct mm_struct * vm_mm; /* 16 8 */ pgprot_t vm_page_prot; /* 24 8 */ union { const vm_flags_t vm_flags; /* 32 8 */ vm_flags_t __vm_flags; /* 32 8 */ }; /* 32 8 */ unsigned int vm_lock_seq; /* 40 4 */ /* XXX 4 bytes hole, try to pack */ struct list_head anon_vma_chain; /* 48 16 */ /* --- cacheline 1 boundary (64 bytes) --- */ struct anon_vma * anon_vma; /* 64 8 */ const struct vm_operations_struct * vm_ops; /* 72 8 */ long unsigned int vm_pgoff; /* 80 8 */ struct file * vm_file; /* 88 8 */ void * vm_private_data; /* 96 8 */ atomic_long_t swap_readahead_info; /* 104 8 */ struct mempolicy * vm_policy; /* 112 8 */ struct vma_numab_state * numab_state; /* 120 8 */ /* --- cacheline 2 boundary (128 bytes) --- */ refcount_t vm_refcnt (__aligned__(64)); /* 128 4 */ /* XXX 4 bytes hole, try to pack */ struct { struct rb_node rb (__aligned__(8)); /* 136 24 */ long unsigned int rb_subtree_last; /* 160 8 */ } __attribute__((__aligned__(8))) shared; /* 136 32 */ struct anon_vma_name * anon_name; /* 168 8 */ struct vm_userfaultfd_ctx vm_userfaultfd_ctx; /* 176 8 */ /* size: 192, cachelines: 3, members: 18 */ /* sum members: 176, holes: 2, sum holes: 8 */ /* padding: 8 */ /* forced alignments: 2, forced holes: 1, sum forced holes: 4 */ } __attribute__((__aligned__(64))); Memory consumption per 1000 VMAs becomes 48 pages: slabinfo after vm_area_struct changes: <name> ... <objsize> <objperslab> <pagesperslab> : ... vm_area_struct ... 192 42 2 : ... Signed-off-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> --- Changes since v9 [1]: - Update vm_area_struct for tests, per Lorenzo Stoakes - Add Reviewed-by, per Lorenzo Stoakes [1] https://lore.kernel.org/all/20250111042604.3230628-13-surenb@google.com/ include/linux/mm_types.h | 38 +++++++++++++++----------------- tools/testing/vma/vma_internal.h | 37 +++++++++++++++---------------- 2 files changed, 36 insertions(+), 39 deletions(-)