[PATCH v4 7/7] mm, slab_common: modify kmalloc_caches[type][idx] to kmalloc_caches[idx][type]

From: Pengfei Li
Date: Sun Sep 15 2019 - 12:53:43 EST


KMALLOC_NORMAL is the most frequently accessed, and kmalloc_caches[]
is initialized by different types of the same size.

So modifying kmalloc_caches[type][idx] to kmalloc_caches[idx][type]
will benefit performance.

$ ./scripts/bloat-o-meter vmlinux.patch_1-6 vmlinux.patch_1-7
add/remove: 0/0 grow/shrink: 2/57 up/down: 8/-457 (-449)
Function old new delta
tg3_self_test 4255 4259 +4
nf_queue 666 670 +4
kmalloc_slab 97 93 -4
i915_sw_fence_await_dma_fence 441 437 -4
__igmp_group_dropped 619 615 -4
gss_import_sec_context 176 170 -6
xhci_alloc_command 212 205 -7
create_kmalloc_caches 155 148 -7
xprt_switch_alloc 136 128 -8
xhci_segment_alloc 297 289 -8
xhci_ring_alloc 369 361 -8
xhci_mem_init 3664 3656 -8
xhci_alloc_virt_device 496 488 -8
xhci_alloc_tt_info 346 338 -8
xhci_alloc_stream_info 718 710 -8
xhci_alloc_container_ctx 215 207 -8
xfrm_policy_alloc 271 263 -8
tcp_sendmsg_locked 3120 3112 -8
tcp_md5_do_add 774 766 -8
tcp_fastopen_defer_connect 270 262 -8
sr_read_tochdr.isra 251 243 -8
sr_read_tocentry.isra 328 320 -8
sr_is_xa 376 368 -8
sr_get_mcn 260 252 -8
selinux_sk_alloc_security 113 105 -8
sdev_evt_send_simple 118 110 -8
sdev_evt_alloc 79 71 -8
scsi_probe_and_add_lun 2938 2930 -8
sbitmap_queue_init_node 418 410 -8
ring_buffer_read_prepare 94 86 -8
request_firmware_nowait 396 388 -8
regulatory_hint_found_beacon 394 386 -8
ohci_urb_enqueue 3176 3168 -8
nla_strdup 142 134 -8
nfs_alloc_seqid 87 79 -8
nfs4_get_state_owner 1040 1032 -8
nfs4_do_close 578 570 -8
nf_ct_tmpl_alloc 85 77 -8
mempool_create_node 164 156 -8
ip_setup_cork 362 354 -8
ip6_setup_cork 1021 1013 -8
gss_create_cred 140 132 -8
drm_flip_work_allocate_task 70 62 -8
dma_pool_alloc 410 402 -8
devres_open_group 214 206 -8
cfg80211_stop_iface 260 252 -8
cfg80211_sinfo_alloc_tid_stats 77 69 -8
cfg80211_port_authorized 212 204 -8
cfg80211_parse_mbssid_data 2397 2389 -8
cfg80211_ibss_joined 335 327 -8
call_usermodehelper_setup 149 141 -8
bpf_prog_alloc_no_stats 182 174 -8
blk_alloc_flush_queue 191 183 -8
bdi_alloc_node 195 187 -8
audit_log_d_path 196 188 -8
_netlbl_catmap_getnode 247 239 -8
____ip_mc_inc_group 475 467 -8
__i915_sw_fence_await_sw_fence 417 405 -12
ida_alloc_range 955 934 -21
Total: Before=14874316, After=14873867, chg -0.00%

Signed-off-by: Pengfei Li <lpf.vector@xxxxxxxxx>
---
include/linux/slab.h | 6 +++---
mm/slab.c | 4 ++--
mm/slab_common.c | 8 ++++----
mm/slub.c | 12 ++++++------
4 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index f53bb6980110..0842db5f7053 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -340,7 +340,7 @@ enum kmalloc_cache_type {

#ifndef CONFIG_SLOB
extern struct kmem_cache *
-kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_CACHE_NUM];
+kmalloc_caches[KMALLOC_CACHE_NUM][NR_KMALLOC_TYPES];

static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags)
{
@@ -582,7 +582,7 @@ static __always_inline void *kmalloc(size_t size, gfp_t flags)
return ZERO_SIZE_PTR;

return kmem_cache_alloc_trace(
- kmalloc_caches[kmalloc_type(flags)][index],
+ kmalloc_caches[index][kmalloc_type(flags)],
flags, size);
#endif
}
@@ -600,7 +600,7 @@ static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
return ZERO_SIZE_PTR;

return kmem_cache_alloc_node_trace(
- kmalloc_caches[kmalloc_type(flags)][i],
+ kmalloc_caches[i][kmalloc_type(flags)],
flags, node, size);
}
#endif
diff --git a/mm/slab.c b/mm/slab.c
index 7bc4e90e1147..079c3e6ced1f 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1246,7 +1246,7 @@ void __init kmem_cache_init(void)
* Initialize the caches that provide memory for the kmem_cache_node
* structures first. Without this, further allocations will bug.
*/
- kmalloc_caches[KMALLOC_NORMAL][INDEX_NODE] = create_kmalloc_cache(
+ kmalloc_caches[INDEX_NODE][KMALLOC_NORMAL] = create_kmalloc_cache(
kmalloc_info[INDEX_NODE].name[KMALLOC_NORMAL],
kmalloc_info[INDEX_NODE].size,
ARCH_KMALLOC_FLAGS, 0,
@@ -1263,7 +1263,7 @@ void __init kmem_cache_init(void)
for_each_online_node(nid) {
init_list(kmem_cache, &init_kmem_cache_node[CACHE_CACHE + nid], nid);

- init_list(kmalloc_caches[KMALLOC_NORMAL][INDEX_NODE],
+ init_list(kmalloc_caches[INDEX_NODE][KMALLOC_NORMAL],
&init_kmem_cache_node[SIZE_NODE + nid], nid);
}
}
diff --git a/mm/slab_common.c b/mm/slab_common.c
index e7903bd28b1f..0f465eae32f6 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1028,7 +1028,7 @@ struct kmem_cache *__init create_kmalloc_cache(const char *name,
}

struct kmem_cache *
-kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_CACHE_NUM] __ro_after_init =
+kmalloc_caches[KMALLOC_CACHE_NUM][NR_KMALLOC_TYPES] __ro_after_init =
{ /* initialization for https://bugs.llvm.org/show_bug.cgi?id=42570 */ };
EXPORT_SYMBOL(kmalloc_caches);

@@ -1090,7 +1090,7 @@ struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags)
index = fls(size - 1) - KMALLOC_IDX_ADJ_2;
}

- return kmalloc_caches[kmalloc_type(flags)][index];
+ return kmalloc_caches[index][kmalloc_type(flags)];
}

#ifdef CONFIG_ZONE_DMA
@@ -1168,7 +1168,7 @@ void __init setup_kmalloc_cache_index_table(void)
static __always_inline void __init
new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags)
{
- kmalloc_caches[type][idx] = create_kmalloc_cache(
+ kmalloc_caches[idx][type] = create_kmalloc_cache(
kmalloc_info[idx].name[type],
kmalloc_info[idx].size, flags, 0,
kmalloc_info[idx].size);
@@ -1184,7 +1184,7 @@ void __init create_kmalloc_caches(slab_flags_t flags)
int i;

for (i = 0; i < KMALLOC_CACHE_NUM; i++) {
- if (!kmalloc_caches[KMALLOC_NORMAL][i])
+ if (!kmalloc_caches[i][KMALLOC_NORMAL])
new_kmalloc_cache(i, KMALLOC_NORMAL, flags);

new_kmalloc_cache(i, KMALLOC_RECLAIM,
diff --git a/mm/slub.c b/mm/slub.c
index 0e92ebdcacc9..e87243a16768 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4711,7 +4711,7 @@ static void __init resiliency_test(void)
pr_err("\n1. kmalloc-16: Clobber Redzone/next pointer 0x12->0x%p\n\n",
p + 16);

- validate_slab_cache(kmalloc_caches[type][1]);
+ validate_slab_cache(kmalloc_caches[1][type]);

/* Hmmm... The next two are dangerous */
p = kzalloc(32, GFP_KERNEL);
@@ -4720,33 +4720,33 @@ static void __init resiliency_test(void)
p);
pr_err("If allocated object is overwritten then not detectable\n\n");

- validate_slab_cache(kmalloc_caches[type][2]);
+ validate_slab_cache(kmalloc_caches[2][type]);
p = kzalloc(64, GFP_KERNEL);
p += 64 + (get_cycles() & 0xff) * sizeof(void *);
*p = 0x56;
pr_err("\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
p);
pr_err("If allocated object is overwritten then not detectable\n\n");
- validate_slab_cache(kmalloc_caches[type][3]);
+ validate_slab_cache(kmalloc_caches[3][type]);

pr_err("\nB. Corruption after free\n");
p = kzalloc(128, GFP_KERNEL);
kfree(p);
*p = 0x78;
pr_err("1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
- validate_slab_cache(kmalloc_caches[type][5]);
+ validate_slab_cache(kmalloc_caches[5][type]);

p = kzalloc(256, GFP_KERNEL);
kfree(p);
p[50] = 0x9a;
pr_err("\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p);
- validate_slab_cache(kmalloc_caches[type][7]);
+ validate_slab_cache(kmalloc_caches[7][type]);

p = kzalloc(512, GFP_KERNEL);
kfree(p);
p[512] = 0xab;
pr_err("\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
- validate_slab_cache(kmalloc_caches[type][8]);
+ validate_slab_cache(kmalloc_caches[8][type]);
}
#else
#ifdef CONFIG_SYSFS
--
2.21.0