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mm, slab: Make kmalloc_info[] contain all types of names

PATCH Superseded Pengfei Li 1 participant 13 messages Sep 15, 2019

Subsystems (2)

v4 of 6 Superseded Latest is v6 →

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Pengfei Li

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#0 lore raw

v4 cover mm, slab: Make kmalloc_info[] contain all types of names

Changes in v4
--
1. [old] abandon patch 4/4
2. [new] patch 4/7:
- return ZERO_SIZE_ALLOC instead 0 for zero sized requests
3. [new] patch 5/7:
- reorder kmalloc_info[], kmalloc_caches[] (in order of size)
- hard to split, so slightly larger
4. [new] patch 6/7:
- initialize kmalloc_cache[] with the same size but different types
5. [new] patch 7/7:
- modify kmalloc_caches[type][idx] to kmalloc_caches[idx][type]

Patch 4-7 are newly added, more information can be obtained from commit messages.

Changes in v3
--
1. restore __initconst (patch 1/4)
2. rename patch 3/4
3. add more clarification for patch 4/4

Changes in v2
--
1. remove __initconst (patch 1/5)
2. squash patch 2/5
3. add ack tag from Vlastimil Babka

There are three types of kmalloc, KMALLOC_NORMAL, KMALLOC_RECLAIM and KMALLOC_DMA.

The name of KMALLOC_NORMAL is contained in kmalloc_info[].name, but the names of KMALLOC_RECLAIM and KMALLOC_DMA are dynamically generated by kmalloc_cache_name().

Patch1 predefines the names of all types of kmalloc to save the time spent dynamically generating names.

These changes make sense, and the time spent by new_kmalloc_cache() has been reduced by approximately 36.3%.

Time spent by new_kmalloc_cache()
(CPU cycles)
5.3-rc7 66264
5.3-rc7+patch_1-3 42188

bloat-o-meter
--

$ ./scripts/bloat-o-meter vmlinux.5.3-rc8 vmlinux.5.3-rc8+patch_1-7
add/remove: 1/2 grow/shrink: 6/65 up/down: 872/-1621 (-749)
Function                                     old     new   delta
all_kmalloc_info                               -     832    +832
crypto_create_tfm                            211     225     +14
ieee80211_key_alloc                         1159    1169     +10
nl80211_parse_sched_scan                    2787    2795      +8
tg3_self_test                               4255    4259      +4
find_get_context.isra                        634     637      +3
sd_probe                                     947     948      +1
nf_queue                                     671     670      -1
trace_parser_get_init                         71      69      -2
pkcs7_verify.cold                            318     316      -2
units                                        323     320      -3
nl80211_set_reg                              642     639      -3
pkcs7_verify                                1503    1495      -8
i915_sw_fence_await_dma_fence                445     437      -8
nla_strdup                                   143     134      -9
kmalloc_slab                                 102      93      -9
xhci_alloc_tt_info                           349     338     -11
xhci_segment_alloc                           303     289     -14
xhci_alloc_container_ctx                     221     207     -14
xfrm_policy_alloc                            277     263     -14
selinux_sk_alloc_security                    119     105     -14
sdev_evt_send_simple                         124     110     -14
sdev_evt_alloc                                85      71     -14
sbitmap_queue_init_node                      424     410     -14
regulatory_hint_found_beacon                 400     386     -14
nf_ct_tmpl_alloc                              91      77     -14
gss_create_cred                              146     132     -14
drm_flip_work_allocate_task                   76      62     -14
cfg80211_stop_iface                          266     252     -14
cfg80211_sinfo_alloc_tid_stats                83      69     -14
cfg80211_port_authorized                     218     204     -14
cfg80211_ibss_joined                         341     327     -14
call_usermodehelper_setup                    155     141     -14
bpf_prog_alloc_no_stats                      188     174     -14
blk_alloc_flush_queue                        197     183     -14
bdi_alloc_node                               201     187     -14
_netlbl_catmap_getnode                       253     239     -14
__igmp_group_dropped                         629     615     -14
____ip_mc_inc_group                          481     467     -14
xhci_alloc_command                           221     205     -16
audit_log_d_path                             204     188     -16
xprt_switch_alloc                            145     128     -17
xhci_ring_alloc                              378     361     -17
xhci_mem_init                               3673    3656     -17
xhci_alloc_virt_device                       505     488     -17
xhci_alloc_stream_info                       727     710     -17
tcp_sendmsg_locked                          3129    3112     -17
tcp_md5_do_add                               783     766     -17
tcp_fastopen_defer_connect                   279     262     -17
sr_read_tochdr.isra                          260     243     -17
sr_read_tocentry.isra                        337     320     -17
sr_is_xa                                     385     368     -17
sr_get_mcn                                   269     252     -17
scsi_probe_and_add_lun                      2947    2930     -17
ring_buffer_read_prepare                     103      86     -17
request_firmware_nowait                      405     388     -17
ohci_urb_enqueue                            3185    3168     -17
nfs_alloc_seqid                               96      79     -17
nfs4_get_state_owner                        1049    1032     -17
nfs4_do_close                                587     570     -17
mempool_create_node                          173     156     -17
ip6_setup_cork                              1030    1013     -17
ida_alloc_range                              951     934     -17
gss_import_sec_context                       187     170     -17
dma_pool_alloc                               419     402     -17
devres_open_group                            223     206     -17
cfg80211_parse_mbssid_data                  2406    2389     -17
ip_setup_cork                                374     354     -20
kmalloc_caches                               336     312     -24
__i915_sw_fence_await_sw_fence               429     405     -24
kmalloc_cache_name                            57       -     -57
new_kmalloc_cache                            112       -    -112
create_kmalloc_caches                        270     148    -122
kmalloc_info                                 432       8    -424
Total: Before=14874616, After=14873867, chg -0.01%

Pengfei Li (7):
mm, slab: Make kmalloc_info[] contain all types of names mm, slab: Remove unused kmalloc_size()
mm, slab_common: Use enum kmalloc_cache_type to iterate over kmalloc
caches
mm, slab: Return ZERO_SIZE_ALLOC for zero sized kmalloc requests mm, slab_common: Make kmalloc_caches[] start at size KMALLOC_MIN_SIZE mm, slab_common: Initialize the same size of kmalloc_caches[] mm, slab_common: Modify kmalloc_caches[type][idx] to
kmalloc_caches[idx][type]

 include/linux/slab.h | 136 ++++++++++++++------------
 mm/slab.c            |  11 ++-
 mm/slab.h            |  10 +-
 mm/slab_common.c     | 224 ++++++++++++++++++-------------------------
 mm/slub.c            |  12 +--
 5 files changed, 183 insertions(+), 210 deletions(-)
Signature · 1 line
2.21.0
author
#1 lore raw

PATCH v4 1/7 mm, slab: Make kmalloc_info[] contain all types of names

There are three types of kmalloc, KMALLOC_NORMAL, KMALLOC_RECLAIM and KMALLOC_DMA.

The name of KMALLOC_NORMAL is contained in kmalloc_info[].name, but the names of KMALLOC_RECLAIM and KMALLOC_DMA are dynamically generated by kmalloc_cache_name().

This patch predefines the names of all types of kmalloc to save the time spent dynamically generating names.

Besides, remove the kmalloc_cache_name() that is no longer used.

---
 mm/slab.c        |  2 +-
 mm/slab.h        |  2 +-
 mm/slab_common.c | 91 ++++++++++++++++++++++++++----------------------
 3 files changed, 51 insertions(+), 44 deletions(-)
mm/slab.c +1 -1
index 9df370558e5d..c42b6211f42e 100644
@@ -1247,7 +1247,7 @@ void __init kmem_cache_init(void)
 	 * structures first.  Without this, further allocations will bug.
 	 */
 	kmalloc_caches[KMALLOC_NORMAL][INDEX_NODE] = create_kmalloc_cache(
-				kmalloc_info[INDEX_NODE].name,
+				kmalloc_info[INDEX_NODE].name[KMALLOC_NORMAL],
 				kmalloc_size(INDEX_NODE), ARCH_KMALLOC_FLAGS,
 				0, kmalloc_size(INDEX_NODE));
 	slab_state = PARTIAL_NODE;
mm/slab.h +1 -1
index 9057b8056b07..2fc8f956906a 100644
@@ -76,7 +76,7 @@ extern struct kmem_cache *kmem_cache;
 
 /* A table of kmalloc cache names and sizes */
 extern const struct kmalloc_info_struct {
-	const char *name;
+	const char *name[NR_KMALLOC_TYPES];
 	unsigned int size;
 } kmalloc_info[];
 
mm/slab_common.c +49 -42

122 lines not on this page · raw message

Signature · 1 line
2.21.0
author
#2 lore raw

PATCH v4 2/7 mm, slab: Remove unused kmalloc_size()

In reply to Pengfei Li

The size of kmalloc can be obtained from kmalloc_info[], so remove kmalloc_size() that will not be used anymore.

---
 include/linux/slab.h | 20 --------------------
 mm/slab.c            |  5 +++--
 mm/slab_common.c     |  5 ++---
 3 files changed, 5 insertions(+), 25 deletions(-)
include/linux/slab.h +0 -20
index 56c9c7eed34e..e773e5764b7b 100644
@@ -557,26 +557,6 @@ static __always_inline void *kmalloc(size_t size, gfp_t flags)
 	return __kmalloc(size, flags);
 }
 
-/*
- * Determine size used for the nth kmalloc cache.
- * return size or 0 if a kmalloc cache for that
- * size does not exist
- */
-static __always_inline unsigned int kmalloc_size(unsigned int n)
-{
-#ifndef CONFIG_SLOB
-	if (n > 2)
-		return 1U << n;
-
-	if (n == 1 && KMALLOC_MIN_SIZE <= 32)
-		return 96;
-
-	if (n == 2 && KMALLOC_MIN_SIZE <= 64)
-		return 192;
-#endif
-	return 0;
-}
-
 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 {
 #ifndef CONFIG_SLOB
mm/slab.c +3 -2
index c42b6211f42e..7bc4e90e1147 100644
@@ -1248,8 +1248,9 @@ void __init kmem_cache_init(void)
 	 */
 	kmalloc_caches[KMALLOC_NORMAL][INDEX_NODE] = create_kmalloc_cache(
 				kmalloc_info[INDEX_NODE].name[KMALLOC_NORMAL],
-				kmalloc_size(INDEX_NODE), ARCH_KMALLOC_FLAGS,
-				0, kmalloc_size(INDEX_NODE));
+				kmalloc_info[INDEX_NODE].size,
+				ARCH_KMALLOC_FLAGS, 0,
+				kmalloc_info[INDEX_NODE].size);
 	slab_state = PARTIAL_NODE;
 	setup_kmalloc_cache_index_table();
 
mm/slab_common.c +2 -3
index 002e16673581..8b542cfcc4f2 100644
@@ -1239,11 +1239,10 @@ void __init create_kmalloc_caches(slab_flags_t flags)
 		struct kmem_cache *s = kmalloc_caches[KMALLOC_NORMAL][i];
 
 		if (s) {
-			unsigned int size = kmalloc_size(i);
-
 			kmalloc_caches[KMALLOC_DMA][i] = create_kmalloc_cache(
 				kmalloc_info[i].name[KMALLOC_DMA],
-				size, SLAB_CACHE_DMA | flags, 0, 0);
+				kmalloc_info[i].size,
+				SLAB_CACHE_DMA | flags, 0, 0);
 		}
 	}
 #endif
Signature · 1 line
2.21.0
author
#3 lore raw

PATCH v4 3/7 mm, slab_common: use enum kmalloc_cache_type to iterate over kmalloc caches

In reply to Pengfei Li

The type of local variable *type* of new_kmalloc_cache() should be enum kmalloc_cache_type instead of int, so correct it.

---
 mm/slab_common.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
mm/slab_common.c +3 -2
index 8b542cfcc4f2..af45b5278fdc 100644
@@ -1192,7 +1192,7 @@ void __init setup_kmalloc_cache_index_table(void)
 }
 
 static void __init
-new_kmalloc_cache(int idx, int type, slab_flags_t flags)
+new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags)
 {
 	if (type == KMALLOC_RECLAIM)
 		flags |= SLAB_RECLAIM_ACCOUNT;
@@ -1210,7 +1210,8 @@ new_kmalloc_cache(int idx, int type, slab_flags_t flags)
  */
 void __init create_kmalloc_caches(slab_flags_t flags)
 {
-	int i, type;
+	int i;
+	enum kmalloc_cache_type type;
 
 	for (type = KMALLOC_NORMAL; type <= KMALLOC_RECLAIM; type++) {
 		for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
Signature · 1 line
2.21.0
author
#4 lore raw

PATCH v4 3/7 mm, slab_common: Use enum kmalloc_cache_type to iterate over kmalloc caches

In reply to Pengfei Li

The type of local variable *type* of new_kmalloc_cache() should be enum kmalloc_cache_type instead of int, so correct it.

---
 mm/slab_common.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
mm/slab_common.c +3 -2
index 8b542cfcc4f2..af45b5278fdc 100644
@@ -1192,7 +1192,7 @@ void __init setup_kmalloc_cache_index_table(void)
 }
 
 static void __init
-new_kmalloc_cache(int idx, int type, slab_flags_t flags)
+new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags)
 {
 	if (type == KMALLOC_RECLAIM)
 		flags |= SLAB_RECLAIM_ACCOUNT;
@@ -1210,7 +1210,8 @@ new_kmalloc_cache(int idx, int type, slab_flags_t flags)
  */
 void __init create_kmalloc_caches(slab_flags_t flags)
 {
-	int i, type;
+	int i;
+	enum kmalloc_cache_type type;
 
 	for (type = KMALLOC_NORMAL; type <= KMALLOC_RECLAIM; type++) {
 		for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
Signature · 1 line
2.21.0
author
#5 lore raw

PATCH v4 4/7 mm, slab: return ZERO_SIZE_ALLOC for zero sized kmalloc requests

In reply to Pengfei Li

This is a preparation patch, just replace 0 with ZERO_SIZE_ALLOC as the return value of zero sized requests.

---
 include/linux/slab.h | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)
include/linux/slab.h +11 -5
index e773e5764b7b..1f05f68f2c3e 100644
@@ -121,14 +121,20 @@
 #define SLAB_DEACTIVATED	((slab_flags_t __force)0x10000000U)
 
 /*
- * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
+ * ZERO_SIZE_ALLOC will be returned by kmalloc_index() if it was zero sized
+ * requests.
  *
+ * After that, ZERO_SIZE_PTR will be returned by the function that called
+ * kmalloc_index().
+
  * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
  *
  * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
  * Both make kfree a no-op.
  */
-#define ZERO_SIZE_PTR ((void *)16)
+#define ZERO_SIZE_ALLOC		(UINT_MAX)
+
+#define ZERO_SIZE_PTR		((void *)16)
 
 #define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
 				(unsigned long)ZERO_SIZE_PTR)
@@ -350,7 +356,7 @@ static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags)
 static __always_inline unsigned int kmalloc_index(size_t size)
 {
 	if (!size)
-		return 0;
+		return ZERO_SIZE_ALLOC;
 
 	if (size <= KMALLOC_MIN_SIZE)
 		return KMALLOC_SHIFT_LOW;
@@ -546,7 +552,7 @@ static __always_inline void *kmalloc(size_t size, gfp_t flags)
 #ifndef CONFIG_SLOB
 		index = kmalloc_index(size);
 
-		if (!index)
+		if (index == ZERO_SIZE_ALLOC)
 			return ZERO_SIZE_PTR;
 
 		return kmem_cache_alloc_trace(
@@ -564,7 +570,7 @@ static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 		size <= KMALLOC_MAX_CACHE_SIZE) {
 		unsigned int i = kmalloc_index(size);
 
-		if (!i)
+		if (i == ZERO_SIZE_ALLOC)
 			return ZERO_SIZE_PTR;
 
 		return kmem_cache_alloc_node_trace(
Signature · 1 line
2.21.0
author
#6 lore raw

PATCH v4 4/7 mm, slab: Return ZERO_SIZE_ALLOC for zero sized kmalloc requests

In reply to Pengfei Li

This is a preparation patch, just replace 0 with ZERO_SIZE_ALLOC as the return value of zero sized requests.

---
 include/linux/slab.h | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)
include/linux/slab.h +11 -5
index e773e5764b7b..1f05f68f2c3e 100644
@@ -121,14 +121,20 @@
 #define SLAB_DEACTIVATED	((slab_flags_t __force)0x10000000U)
 
 /*
- * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
+ * ZERO_SIZE_ALLOC will be returned by kmalloc_index() if it was zero sized
+ * requests.
  *
+ * After that, ZERO_SIZE_PTR will be returned by the function that called
+ * kmalloc_index().
+
  * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
  *
  * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
  * Both make kfree a no-op.
  */
-#define ZERO_SIZE_PTR ((void *)16)
+#define ZERO_SIZE_ALLOC		(UINT_MAX)
+
+#define ZERO_SIZE_PTR		((void *)16)
 
 #define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
 				(unsigned long)ZERO_SIZE_PTR)
@@ -350,7 +356,7 @@ static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags)
 static __always_inline unsigned int kmalloc_index(size_t size)
 {
 	if (!size)
-		return 0;
+		return ZERO_SIZE_ALLOC;
 
 	if (size <= KMALLOC_MIN_SIZE)
 		return KMALLOC_SHIFT_LOW;
@@ -546,7 +552,7 @@ static __always_inline void *kmalloc(size_t size, gfp_t flags)
 #ifndef CONFIG_SLOB
 		index = kmalloc_index(size);
 
-		if (!index)
+		if (index == ZERO_SIZE_ALLOC)
 			return ZERO_SIZE_PTR;
 
 		return kmem_cache_alloc_trace(
@@ -564,7 +570,7 @@ static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 		size <= KMALLOC_MAX_CACHE_SIZE) {
 		unsigned int i = kmalloc_index(size);
 
-		if (!i)
+		if (i == ZERO_SIZE_ALLOC)
 			return ZERO_SIZE_PTR;
 
 		return kmem_cache_alloc_node_trace(
Signature · 1 line
2.21.0
author
#7 lore raw

PATCH v4 5/7 mm, slab_common: make kmalloc_caches[] start at size KMALLOC_MIN_SIZE

In reply to Pengfei Li

Currently, kmalloc_cache[] is not sorted by size, kmalloc_cache[0] is kmalloc-96, kmalloc_cache[1] is kmalloc-192 (when ARCH_DMA_MINALIGN is not defined).

As suggested by Vlastimil Babka,

"Since you're doing these cleanups, have you considered reordering kmalloc_info, size_index, kmalloc_index() etc so that sizes 96 and 192 are ordered naturally between 64, 128 and 256? That should remove various special casing such as in create_kmalloc_caches(). I can't guarantee it will be possible without breaking e.g. constant folding optimizations etc., but seems to me it should be feasible. (There are definitely more places to change than those I listed.)"

So this patch reordered kmalloc_info[], kmalloc_caches[], and modified kmalloc_index() and kmalloc_slab() accordingly.

As a result, there is no subtle judgment about size in create_kmalloc_caches(). And initialize kmalloc_cache[] from 0 instead of KMALLOC_SHIFT_LOW.

I used ./scripts/bloat-o-meter to measure the impact of this patch on performance. The results show that it brings some benefits.

Considering the size change of kmalloc_info[], the size of the code is actually about 641 bytes less.

(Note: The original kmalloc_info[] was renamed to all_kmalloc_info[])

$ ./scripts/bloat-o-meter vmlinux.old vmlinux.patch_1-5
add/remove: 1/2 grow/shrink: 6/64 up/down: 872/-1113 (-241)
Function                                     old     new   delta
all_kmalloc_info                               -     832    +832
crypto_create_tfm                            211     225     +14
ieee80211_key_alloc                         1159    1169     +10
nl80211_parse_sched_scan                    2787    2795      +8
ida_alloc_range                              951     955      +4
find_get_context.isra                        634     637      +3
sd_probe                                     947     948      +1
nla_strdup                                   143     142      -1
trace_parser_get_init                         71      69      -2
pkcs7_verify.cold                            318     316      -2
xhci_alloc_tt_info                           349     346      -3
units                                        323     320      -3
nl80211_set_reg                              642     639      -3
i915_sw_fence_await_dma_fence                445     441      -4
nf_queue                                     671     666      -5
kmalloc_slab                                 102      97      -5
xhci_segment_alloc                           303     297      -6
xhci_alloc_container_ctx                     221     215      -6
xfrm_policy_alloc                            277     271      -6
selinux_sk_alloc_security                    119     113      -6
sdev_evt_send_simple                         124     118      -6
sdev_evt_alloc                                85      79      -6
sbitmap_queue_init_node                      424     418      -6
regulatory_hint_found_beacon                 400     394      -6
nf_ct_tmpl_alloc                              91      85      -6
gss_create_cred                              146     140      -6
drm_flip_work_allocate_task                   76      70      -6
cfg80211_stop_iface                          266     260      -6
cfg80211_sinfo_alloc_tid_stats                83      77      -6
cfg80211_port_authorized                     218     212      -6
cfg80211_ibss_joined                         341     335      -6
call_usermodehelper_setup                    155     149      -6
bpf_prog_alloc_no_stats                      188     182      -6
blk_alloc_flush_queue                        197     191      -6
bdi_alloc_node                               201     195      -6
_netlbl_catmap_getnode                       253     247      -6
____ip_mc_inc_group                          481     475      -6
pkcs7_verify                                1503    1495      -8
audit_log_d_path                             204     196      -8
xprt_switch_alloc                            145     136      -9
xhci_ring_alloc                              378     369      -9
xhci_mem_init                               3673    3664      -9
xhci_alloc_virt_device                       505     496      -9
xhci_alloc_stream_info                       727     718      -9
xhci_alloc_command                           221     212      -9
tcp_sendmsg_locked                          3129    3120      -9
tcp_md5_do_add                               783     774      -9
tcp_fastopen_defer_connect                   279     270      -9
sr_read_tochdr.isra                          260     251      -9
sr_read_tocentry.isra                        337     328      -9
sr_is_xa                                     385     376      -9
sr_get_mcn                                   269     260      -9
scsi_probe_and_add_lun                      2947    2938      -9
ring_buffer_read_prepare                     103      94      -9
request_firmware_nowait                      405     396      -9
ohci_urb_enqueue                            3185    3176      -9
nfs_alloc_seqid                               96      87      -9
nfs4_get_state_owner                        1049    1040      -9
nfs4_do_close                                587     578      -9
mempool_create_node                          173     164      -9
ip6_setup_cork                              1030    1021      -9
dma_pool_alloc                               419     410      -9
devres_open_group                            223     214      -9
cfg80211_parse_mbssid_data                  2406    2397      -9
__igmp_group_dropped                         629     619     -10
gss_import_sec_context                       187     176     -11
ip_setup_cork                                374     362     -12
__i915_sw_fence_await_sw_fence               429     417     -12
kmalloc_caches                               336     312     -24
create_kmalloc_caches                        270     214     -56
kmalloc_cache_name                            57       -     -57
new_kmalloc_cache                            112       -    -112
kmalloc_info                                 432       8    -424
Total: Before=14874616, After=14874375, chg -0.00%
---
 include/linux/slab.h |  96 ++++++++++++++++----------
 mm/slab.h            |  10 +--
 mm/slab_common.c     | 158 ++++++++++++++++---------------------------
 mm/slub.c            |  12 ++--
 4 files changed, 133 insertions(+), 143 deletions(-)
include/linux/slab.h +61 -35
index 1f05f68f2c3e..f53bb6980110 100644
@@ -297,6 +297,23 @@ static inline void __check_heap_object(const void *ptr, unsigned long n,
 #define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW)
 #endif
 
+#define KMALLOC_CACHE_MIN_NUM	(KMALLOC_SHIFT_HIGH - KMALLOC_SHIFT_LOW + 1)
+
+#if KMALLOC_MIN_SIZE > 64
+	#define KMALLOC_SIZE_96_EXIST	(0)
+	#define KMALLOC_SIZE_192_EXIST	(0)
+#elif KMALLOC_MIN_SIZE > 32
+	#define KMALLOC_SIZE_96_EXIST	(0)
+	#define KMALLOC_SIZE_192_EXIST	(1)
+#else
+	#define KMALLOC_SIZE_96_EXIST	(1)
+	#define KMALLOC_SIZE_192_EXIST	(1)
+#endif
+
+#define KMALLOC_CACHE_NUM	(KMALLOC_CACHE_MIN_NUM			\
+					+ KMALLOC_SIZE_96_EXIST		\
+					+ KMALLOC_SIZE_192_EXIST)
+
 /*
  * This restriction comes from byte sized index implementation.
  * Page size is normally 2^12 bytes and, in this case, if we want to use
@@ -323,7 +340,7 @@ enum kmalloc_cache_type {
 
 #ifndef CONFIG_SLOB
 extern struct kmem_cache *
-kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1];
+kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_CACHE_NUM];
 
 static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags)
 {
@@ -345,13 +362,18 @@ static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags)
 #endif
 }
 
+/* kmalloc_index adjust size: (0, 96] */
+#define KMALLOC_IDX_ADJ_0	(KMALLOC_SHIFT_LOW)
+
+/* kmalloc_index adjust size: (96, 192] */
+#define KMALLOC_IDX_ADJ_1	(KMALLOC_IDX_ADJ_0 - KMALLOC_SIZE_96_EXIST)
+
+/* kmalloc_index adjust size: (192, N] */
+#define KMALLOC_IDX_ADJ_2	(KMALLOC_IDX_ADJ_1 - KMALLOC_SIZE_192_EXIST)
+
 /*
  * Figure out which kmalloc slab an allocation of a certain size
  * belongs to.
- * 0 = zero alloc
- * 1 =  65 .. 96 bytes
- * 2 = 129 .. 192 bytes
- * n = 2^(n-1)+1 .. 2^n
  */
 static __always_inline unsigned int kmalloc_index(size_t size)
 {
@@ -359,36 +381,40 @@ static __always_inline unsigned int kmalloc_index(size_t size)
 		return ZERO_SIZE_ALLOC;
 
 	if (size <= KMALLOC_MIN_SIZE)
-		return KMALLOC_SHIFT_LOW;
-
-	if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
-		return 1;
-	if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
-		return 2;
-	if (size <=          8) return 3;
-	if (size <=         16) return 4;
-	if (size <=         32) return 5;
-	if (size <=         64) return 6;
-	if (size <=        128) return 7;
-	if (size <=        256) return 8;
-	if (size <=        512) return 9;
-	if (size <=       1024) return 10;
-	if (size <=   2 * 1024) return 11;
-	if (size <=   4 * 1024) return 12;
-	if (size <=   8 * 1024) return 13;
-	if (size <=  16 * 1024) return 14;
-	if (size <=  32 * 1024) return 15;
-	if (size <=  64 * 1024) return 16;
-	if (size <= 128 * 1024) return 17;
-	if (size <= 256 * 1024) return 18;
-	if (size <= 512 * 1024) return 19;
-	if (size <= 1024 * 1024) return 20;
-	if (size <=  2 * 1024 * 1024) return 21;
-	if (size <=  4 * 1024 * 1024) return 22;
-	if (size <=  8 * 1024 * 1024) return 23;
-	if (size <=  16 * 1024 * 1024) return 24;
-	if (size <=  32 * 1024 * 1024) return 25;
-	if (size <=  64 * 1024 * 1024) return 26;
+		return 0;
+
+#if KMALLOC_SIZE_96_EXIST == 1
+	if (size > 64 && size <= 96) return (7 - KMALLOC_IDX_ADJ_0);
+#endif
+
+#if KMALLOC_SIZE_192_EXIST == 1
+	if (size > 128 && size <= 192) return (8 - KMALLOC_IDX_ADJ_1);
+#endif
+
+	if (size <=                8) return ( 3 - KMALLOC_IDX_ADJ_0);
+	if (size <=               16) return ( 4 - KMALLOC_IDX_ADJ_0);
+	if (size <=               32) return ( 5 - KMALLOC_IDX_ADJ_0);
+	if (size <=               64) return ( 6 - KMALLOC_IDX_ADJ_0);
+	if (size <=              128) return ( 7 - KMALLOC_IDX_ADJ_1);
+	if (size <=              256) return ( 8 - KMALLOC_IDX_ADJ_2);
+	if (size <=              512) return ( 9 - KMALLOC_IDX_ADJ_2);
+	if (size <=             1024) return (10 - KMALLOC_IDX_ADJ_2);
+	if (size <=         2 * 1024) return (11 - KMALLOC_IDX_ADJ_2);
+	if (size <=         4 * 1024) return (12 - KMALLOC_IDX_ADJ_2);
+	if (size <=         8 * 1024) return (13 - KMALLOC_IDX_ADJ_2);
+	if (size <=        16 * 1024) return (14 - KMALLOC_IDX_ADJ_2);
+	if (size <=        32 * 1024) return (15 - KMALLOC_IDX_ADJ_2);
+	if (size <=        64 * 1024) return (16 - KMALLOC_IDX_ADJ_2);
+	if (size <=       128 * 1024) return (17 - KMALLOC_IDX_ADJ_2);
+	if (size <=       256 * 1024) return (18 - KMALLOC_IDX_ADJ_2);
+	if (size <=       512 * 1024) return (19 - KMALLOC_IDX_ADJ_2);
+	if (size <=      1024 * 1024) return (20 - KMALLOC_IDX_ADJ_2);
+	if (size <=  2 * 1024 * 1024) return (21 - KMALLOC_IDX_ADJ_2);
+	if (size <=  4 * 1024 * 1024) return (22 - KMALLOC_IDX_ADJ_2);
+	if (size <=  8 * 1024 * 1024) return (23 - KMALLOC_IDX_ADJ_2);
+	if (size <= 16 * 1024 * 1024) return (24 - KMALLOC_IDX_ADJ_2);
+	if (size <= 32 * 1024 * 1024) return (25 - KMALLOC_IDX_ADJ_2);
+	if (size <= 64 * 1024 * 1024) return (26 - KMALLOC_IDX_ADJ_2);
 	BUG();
 
 	/* Will never be reached. Needed because the compiler may complain */
mm/slab.h +6 -4
index 2fc8f956906a..3ada65ef1118 100644
@@ -63,6 +63,11 @@ enum slab_state {
 	FULL			/* Everything is working */
 };
 
+struct kmalloc_info_struct {
+	const char *name[NR_KMALLOC_TYPES];
+	unsigned int size;
+};
+
 extern enum slab_state slab_state;
 
 /* The slab cache mutex protects the management structures during changes */
@@ -75,10 +80,7 @@ extern struct list_head slab_caches;
 extern struct kmem_cache *kmem_cache;
 
 /* A table of kmalloc cache names and sizes */
-extern const struct kmalloc_info_struct {
-	const char *name[NR_KMALLOC_TYPES];
-	unsigned int size;
-} kmalloc_info[];
+extern const struct kmalloc_info_struct * const kmalloc_info;
 
 #ifndef CONFIG_SLOB
 /* Kmalloc array related functions */
mm/slab_common.c +60 -98

211 lines not on this page · raw message

mm/slub.c +6 -6
index 8834563cdb4b..0e92ebdcacc9 100644
@@ -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][4]);
+	validate_slab_cache(kmalloc_caches[type][1]);
 
 	/* 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][5]);
+	validate_slab_cache(kmalloc_caches[type][2]);
 	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][6]);
+	validate_slab_cache(kmalloc_caches[type][3]);
 
 	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][7]);
+	validate_slab_cache(kmalloc_caches[type][5]);
 
 	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][8]);
+	validate_slab_cache(kmalloc_caches[type][7]);
 
 	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][9]);
+	validate_slab_cache(kmalloc_caches[type][8]);
 }
 #else
 #ifdef CONFIG_SYSFS
Signature · 1 line
2.21.0
author
#8 lore raw

PATCH v4 5/7 mm, slab_common: Make kmalloc_caches[] start at size KMALLOC_MIN_SIZE

In reply to Pengfei Li

Currently, kmalloc_cache[] is not sorted by size, kmalloc_cache[0] is kmalloc-96, kmalloc_cache[1] is kmalloc-192 (when ARCH_DMA_MINALIGN is not defined).

As suggested by Vlastimil Babka,

"Since you're doing these cleanups, have you considered reordering kmalloc_info, size_index, kmalloc_index() etc so that sizes 96 and 192 are ordered naturally between 64, 128 and 256? That should remove various special casing such as in create_kmalloc_caches(). I can't guarantee it will be possible without breaking e.g. constant folding optimizations etc., but seems to me it should be feasible. (There are definitely more places to change than those I listed.)"

So this patch reordered kmalloc_info[], kmalloc_caches[], and modified kmalloc_index() and kmalloc_slab() accordingly.

As a result, there is no subtle judgment about size in create_kmalloc_caches(). And initialize kmalloc_cache[] from 0 instead of KMALLOC_SHIFT_LOW.

I used ./scripts/bloat-o-meter to measure the impact of this patch on performance. The results show that it brings some benefits.

Considering the size change of kmalloc_info[], the size of the code is actually about 641 bytes less.

(Note: The original kmalloc_info[] was renamed to all_kmalloc_info[])

$ ./scripts/bloat-o-meter vmlinux.old vmlinux.patch_1-5
add/remove: 1/2 grow/shrink: 6/64 up/down: 872/-1113 (-241)
Function                                     old     new   delta
all_kmalloc_info                               -     832    +832
crypto_create_tfm                            211     225     +14
ieee80211_key_alloc                         1159    1169     +10
nl80211_parse_sched_scan                    2787    2795      +8
ida_alloc_range                              951     955      +4
find_get_context.isra                        634     637      +3
sd_probe                                     947     948      +1
nla_strdup                                   143     142      -1
trace_parser_get_init                         71      69      -2
pkcs7_verify.cold                            318     316      -2
xhci_alloc_tt_info                           349     346      -3
units                                        323     320      -3
nl80211_set_reg                              642     639      -3
i915_sw_fence_await_dma_fence                445     441      -4
nf_queue                                     671     666      -5
kmalloc_slab                                 102      97      -5
xhci_segment_alloc                           303     297      -6
xhci_alloc_container_ctx                     221     215      -6
xfrm_policy_alloc                            277     271      -6
selinux_sk_alloc_security                    119     113      -6
sdev_evt_send_simple                         124     118      -6
sdev_evt_alloc                                85      79      -6
sbitmap_queue_init_node                      424     418      -6
regulatory_hint_found_beacon                 400     394      -6
nf_ct_tmpl_alloc                              91      85      -6
gss_create_cred                              146     140      -6
drm_flip_work_allocate_task                   76      70      -6
cfg80211_stop_iface                          266     260      -6
cfg80211_sinfo_alloc_tid_stats                83      77      -6
cfg80211_port_authorized                     218     212      -6
cfg80211_ibss_joined                         341     335      -6
call_usermodehelper_setup                    155     149      -6
bpf_prog_alloc_no_stats                      188     182      -6
blk_alloc_flush_queue                        197     191      -6
bdi_alloc_node                               201     195      -6
_netlbl_catmap_getnode                       253     247      -6
____ip_mc_inc_group                          481     475      -6
pkcs7_verify                                1503    1495      -8
audit_log_d_path                             204     196      -8
xprt_switch_alloc                            145     136      -9
xhci_ring_alloc                              378     369      -9
xhci_mem_init                               3673    3664      -9
xhci_alloc_virt_device                       505     496      -9
xhci_alloc_stream_info                       727     718      -9
xhci_alloc_command                           221     212      -9
tcp_sendmsg_locked                          3129    3120      -9
tcp_md5_do_add                               783     774      -9
tcp_fastopen_defer_connect                   279     270      -9
sr_read_tochdr.isra                          260     251      -9
sr_read_tocentry.isra                        337     328      -9
sr_is_xa                                     385     376      -9
sr_get_mcn                                   269     260      -9
scsi_probe_and_add_lun                      2947    2938      -9
ring_buffer_read_prepare                     103      94      -9
request_firmware_nowait                      405     396      -9
ohci_urb_enqueue                            3185    3176      -9
nfs_alloc_seqid                               96      87      -9
nfs4_get_state_owner                        1049    1040      -9
nfs4_do_close                                587     578      -9
mempool_create_node                          173     164      -9
ip6_setup_cork                              1030    1021      -9
dma_pool_alloc                               419     410      -9
devres_open_group                            223     214      -9
cfg80211_parse_mbssid_data                  2406    2397      -9
__igmp_group_dropped                         629     619     -10
gss_import_sec_context                       187     176     -11
ip_setup_cork                                374     362     -12
__i915_sw_fence_await_sw_fence               429     417     -12
kmalloc_caches                               336     312     -24
create_kmalloc_caches                        270     214     -56
kmalloc_cache_name                            57       -     -57
new_kmalloc_cache                            112       -    -112
kmalloc_info                                 432       8    -424
Total: Before=14874616, After=14874375, chg -0.00%
---
 include/linux/slab.h |  96 ++++++++++++++++----------
 mm/slab.h            |  10 +--
 mm/slab_common.c     | 158 ++++++++++++++++---------------------------
 mm/slub.c            |  12 ++--
 4 files changed, 133 insertions(+), 143 deletions(-)
include/linux/slab.h +61 -35
index 1f05f68f2c3e..f53bb6980110 100644
@@ -297,6 +297,23 @@ static inline void __check_heap_object(const void *ptr, unsigned long n,
 #define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW)
 #endif
 
+#define KMALLOC_CACHE_MIN_NUM	(KMALLOC_SHIFT_HIGH - KMALLOC_SHIFT_LOW + 1)
+
+#if KMALLOC_MIN_SIZE > 64
+	#define KMALLOC_SIZE_96_EXIST	(0)
+	#define KMALLOC_SIZE_192_EXIST	(0)
+#elif KMALLOC_MIN_SIZE > 32
+	#define KMALLOC_SIZE_96_EXIST	(0)
+	#define KMALLOC_SIZE_192_EXIST	(1)
+#else
+	#define KMALLOC_SIZE_96_EXIST	(1)
+	#define KMALLOC_SIZE_192_EXIST	(1)
+#endif
+
+#define KMALLOC_CACHE_NUM	(KMALLOC_CACHE_MIN_NUM			\
+					+ KMALLOC_SIZE_96_EXIST		\
+					+ KMALLOC_SIZE_192_EXIST)
+
 /*
  * This restriction comes from byte sized index implementation.
  * Page size is normally 2^12 bytes and, in this case, if we want to use
@@ -323,7 +340,7 @@ enum kmalloc_cache_type {
 
 #ifndef CONFIG_SLOB
 extern struct kmem_cache *
-kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1];
+kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_CACHE_NUM];
 
 static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags)
 {
@@ -345,13 +362,18 @@ static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags)
 #endif
 }
 
+/* kmalloc_index adjust size: (0, 96] */
+#define KMALLOC_IDX_ADJ_0	(KMALLOC_SHIFT_LOW)
+
+/* kmalloc_index adjust size: (96, 192] */
+#define KMALLOC_IDX_ADJ_1	(KMALLOC_IDX_ADJ_0 - KMALLOC_SIZE_96_EXIST)
+
+/* kmalloc_index adjust size: (192, N] */
+#define KMALLOC_IDX_ADJ_2	(KMALLOC_IDX_ADJ_1 - KMALLOC_SIZE_192_EXIST)
+
 /*
  * Figure out which kmalloc slab an allocation of a certain size
  * belongs to.
- * 0 = zero alloc
- * 1 =  65 .. 96 bytes
- * 2 = 129 .. 192 bytes
- * n = 2^(n-1)+1 .. 2^n
  */
 static __always_inline unsigned int kmalloc_index(size_t size)
 {
@@ -359,36 +381,40 @@ static __always_inline unsigned int kmalloc_index(size_t size)
 		return ZERO_SIZE_ALLOC;
 
 	if (size <= KMALLOC_MIN_SIZE)
-		return KMALLOC_SHIFT_LOW;
-
-	if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
-		return 1;
-	if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
-		return 2;
-	if (size <=          8) return 3;
-	if (size <=         16) return 4;
-	if (size <=         32) return 5;
-	if (size <=         64) return 6;
-	if (size <=        128) return 7;
-	if (size <=        256) return 8;
-	if (size <=        512) return 9;
-	if (size <=       1024) return 10;
-	if (size <=   2 * 1024) return 11;
-	if (size <=   4 * 1024) return 12;
-	if (size <=   8 * 1024) return 13;
-	if (size <=  16 * 1024) return 14;
-	if (size <=  32 * 1024) return 15;
-	if (size <=  64 * 1024) return 16;
-	if (size <= 128 * 1024) return 17;
-	if (size <= 256 * 1024) return 18;
-	if (size <= 512 * 1024) return 19;
-	if (size <= 1024 * 1024) return 20;
-	if (size <=  2 * 1024 * 1024) return 21;
-	if (size <=  4 * 1024 * 1024) return 22;
-	if (size <=  8 * 1024 * 1024) return 23;
-	if (size <=  16 * 1024 * 1024) return 24;
-	if (size <=  32 * 1024 * 1024) return 25;
-	if (size <=  64 * 1024 * 1024) return 26;
+		return 0;
+
+#if KMALLOC_SIZE_96_EXIST == 1
+	if (size > 64 && size <= 96) return (7 - KMALLOC_IDX_ADJ_0);
+#endif
+
+#if KMALLOC_SIZE_192_EXIST == 1
+	if (size > 128 && size <= 192) return (8 - KMALLOC_IDX_ADJ_1);
+#endif
+
+	if (size <=                8) return ( 3 - KMALLOC_IDX_ADJ_0);
+	if (size <=               16) return ( 4 - KMALLOC_IDX_ADJ_0);
+	if (size <=               32) return ( 5 - KMALLOC_IDX_ADJ_0);
+	if (size <=               64) return ( 6 - KMALLOC_IDX_ADJ_0);
+	if (size <=              128) return ( 7 - KMALLOC_IDX_ADJ_1);
+	if (size <=              256) return ( 8 - KMALLOC_IDX_ADJ_2);
+	if (size <=              512) return ( 9 - KMALLOC_IDX_ADJ_2);
+	if (size <=             1024) return (10 - KMALLOC_IDX_ADJ_2);
+	if (size <=         2 * 1024) return (11 - KMALLOC_IDX_ADJ_2);
+	if (size <=         4 * 1024) return (12 - KMALLOC_IDX_ADJ_2);
+	if (size <=         8 * 1024) return (13 - KMALLOC_IDX_ADJ_2);
+	if (size <=        16 * 1024) return (14 - KMALLOC_IDX_ADJ_2);
+	if (size <=        32 * 1024) return (15 - KMALLOC_IDX_ADJ_2);
+	if (size <=        64 * 1024) return (16 - KMALLOC_IDX_ADJ_2);
+	if (size <=       128 * 1024) return (17 - KMALLOC_IDX_ADJ_2);
+	if (size <=       256 * 1024) return (18 - KMALLOC_IDX_ADJ_2);
+	if (size <=       512 * 1024) return (19 - KMALLOC_IDX_ADJ_2);
+	if (size <=      1024 * 1024) return (20 - KMALLOC_IDX_ADJ_2);
+	if (size <=  2 * 1024 * 1024) return (21 - KMALLOC_IDX_ADJ_2);
+	if (size <=  4 * 1024 * 1024) return (22 - KMALLOC_IDX_ADJ_2);
+	if (size <=  8 * 1024 * 1024) return (23 - KMALLOC_IDX_ADJ_2);
+	if (size <= 16 * 1024 * 1024) return (24 - KMALLOC_IDX_ADJ_2);
+	if (size <= 32 * 1024 * 1024) return (25 - KMALLOC_IDX_ADJ_2);
+	if (size <= 64 * 1024 * 1024) return (26 - KMALLOC_IDX_ADJ_2);
 	BUG();
 
 	/* Will never be reached. Needed because the compiler may complain */
mm/slab.h +6 -4
index 2fc8f956906a..3ada65ef1118 100644
@@ -63,6 +63,11 @@ enum slab_state {
 	FULL			/* Everything is working */
 };
 
+struct kmalloc_info_struct {
+	const char *name[NR_KMALLOC_TYPES];
+	unsigned int size;
+};
+
 extern enum slab_state slab_state;
 
 /* The slab cache mutex protects the management structures during changes */
@@ -75,10 +80,7 @@ extern struct list_head slab_caches;
 extern struct kmem_cache *kmem_cache;
 
 /* A table of kmalloc cache names and sizes */
-extern const struct kmalloc_info_struct {
-	const char *name[NR_KMALLOC_TYPES];
-	unsigned int size;
-} kmalloc_info[];
+extern const struct kmalloc_info_struct * const kmalloc_info;
 
 #ifndef CONFIG_SLOB
 /* Kmalloc array related functions */
mm/slab_common.c +60 -98

211 lines not on this page · raw message

mm/slub.c +6 -6
index 8834563cdb4b..0e92ebdcacc9 100644
@@ -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][4]);
+	validate_slab_cache(kmalloc_caches[type][1]);
 
 	/* 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][5]);
+	validate_slab_cache(kmalloc_caches[type][2]);
 	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][6]);
+	validate_slab_cache(kmalloc_caches[type][3]);
 
 	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][7]);
+	validate_slab_cache(kmalloc_caches[type][5]);
 
 	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][8]);
+	validate_slab_cache(kmalloc_caches[type][7]);
 
 	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][9]);
+	validate_slab_cache(kmalloc_caches[type][8]);
 }
 #else
 #ifdef CONFIG_SYSFS
Signature · 1 line
2.21.0
author
#9 lore raw

PATCH v4 6/7 mm, slab_common: initialize the same size of kmalloc_caches[]

In reply to Pengfei Li

In the current implementation, KMALLOC_RECLAIM is not initialized until all the KMALLOC_NORMAL sizes have been initialized.

But for a particular size, create_kmalloc_caches() can be executed faster by initializing different types of kmalloc in order.

$ ./scripts/bloat-o-meter vmlinux.old vmlinux.patch_1-5
add/remove: 1/2 grow/shrink: 6/64 up/down: 872/-1113 (-241)
Function                                     old     new   delta
create_kmalloc_caches                        270     214     -56
$ ./scripts/bloat-o-meter vmlinux.old vmlinux.patch_1-6
add/remove: 1/2 grow/shrink: 6/64 up/down: 872/-1172 (-300)
Function                                     old     new   delta
create_kmalloc_caches                        270     155    -115

We can see that it really gets the benefits.

Besides, KMALLOC_DMA will be initialized after "slab_state = UP", this does not seem to be necessary.

Commit f97d5f634d3b ("slab: Common function to create the kmalloc array") introduces create_kmalloc_caches().

And I found that for SLAB, KMALLOC_DMA is initialized before "slab_state = UP". But for SLUB, KMALLOC_DMA is initialized after "slab_state = UP".

Based on this fact, I think it is okay to initialize KMALLOC_DMA before "slab_state = UP".

---
 mm/slab_common.c | 35 ++++++++++++-----------------------
 1 file changed, 12 insertions(+), 23 deletions(-)
mm/slab_common.c +12 -23
index 2aed30deb071..e7903bd28b1f 100644
@@ -1165,12 +1165,9 @@ void __init setup_kmalloc_cache_index_table(void)
 		size_index[size_index_elem(i)] = 0;
 }
 
-static void __init
+static __always_inline void __init
 new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags)
 {
-	if (type == KMALLOC_RECLAIM)
-		flags |= SLAB_RECLAIM_ACCOUNT;
-
 	kmalloc_caches[type][idx] = create_kmalloc_cache(
 					kmalloc_info[idx].name[type],
 					kmalloc_info[idx].size, flags, 0,
@@ -1185,30 +1182,22 @@ new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags)
 void __init create_kmalloc_caches(slab_flags_t flags)
 {
 	int i;
-	enum kmalloc_cache_type type;
 
-	for (type = KMALLOC_NORMAL; type <= KMALLOC_RECLAIM; type++) {
-		for (i = 0; i < KMALLOC_CACHE_NUM; i++) {
-			if (!kmalloc_caches[type][i])
-				new_kmalloc_cache(i, type, flags);
-		}
-	}
+	for (i = 0; i < KMALLOC_CACHE_NUM; i++) {
+		if (!kmalloc_caches[KMALLOC_NORMAL][i])
+			new_kmalloc_cache(i, KMALLOC_NORMAL, flags);
 
-	/* Kmalloc array is now usable */
-	slab_state = UP;
+		new_kmalloc_cache(i, KMALLOC_RECLAIM,
+					flags | SLAB_RECLAIM_ACCOUNT);
 
 #ifdef CONFIG_ZONE_DMA
-	for (i = 0; i < KMALLOC_CACHE_NUM; i++) {
-		struct kmem_cache *s = kmalloc_caches[KMALLOC_NORMAL][i];
-
-		if (s) {
-			kmalloc_caches[KMALLOC_DMA][i] = create_kmalloc_cache(
-				kmalloc_info[i].name[KMALLOC_DMA],
-				kmalloc_info[i].size,
-				SLAB_CACHE_DMA | flags, 0, 0);
-		}
-	}
+		new_kmalloc_cache(i, KMALLOC_DMA,
+					flags | SLAB_CACHE_DMA);
 #endif
+	}
+
+	/* Kmalloc array is now usable */
+	slab_state = UP;
 }
 #endif /* !CONFIG_SLOB */
 
Signature · 1 line
2.21.0
author
#10 lore raw

PATCH v4 6/7 mm, slab_common: Initialize the same size of kmalloc_caches[]

In reply to Pengfei Li

In the current implementation, KMALLOC_RECLAIM is not initialized until all the KMALLOC_NORMAL sizes have been initialized.

But for a particular size, create_kmalloc_caches() can be executed faster by initializing different types of kmalloc in order.

$ ./scripts/bloat-o-meter vmlinux.old vmlinux.patch_1-5
add/remove: 1/2 grow/shrink: 6/64 up/down: 872/-1113 (-241)
Function                                     old     new   delta
create_kmalloc_caches                        270     214     -56
$ ./scripts/bloat-o-meter vmlinux.old vmlinux.patch_1-6
add/remove: 1/2 grow/shrink: 6/64 up/down: 872/-1172 (-300)
Function                                     old     new   delta
create_kmalloc_caches                        270     155    -115

We can see that it really gets the benefits.

Besides, KMALLOC_DMA will be initialized after "slab_state = UP", this does not seem to be necessary.

Commit f97d5f634d3b ("slab: Common function to create the kmalloc array") introduces create_kmalloc_caches().

And I found that for SLAB, KMALLOC_DMA is initialized before "slab_state = UP". But for SLUB, KMALLOC_DMA is initialized after "slab_state = UP".

Based on this fact, I think it is okay to initialize KMALLOC_DMA before "slab_state = UP".

---
 mm/slab_common.c | 35 ++++++++++++-----------------------
 1 file changed, 12 insertions(+), 23 deletions(-)
mm/slab_common.c +12 -23
index 2aed30deb071..e7903bd28b1f 100644
@@ -1165,12 +1165,9 @@ void __init setup_kmalloc_cache_index_table(void)
 		size_index[size_index_elem(i)] = 0;
 }
 
-static void __init
+static __always_inline void __init
 new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags)
 {
-	if (type == KMALLOC_RECLAIM)
-		flags |= SLAB_RECLAIM_ACCOUNT;
-
 	kmalloc_caches[type][idx] = create_kmalloc_cache(
 					kmalloc_info[idx].name[type],
 					kmalloc_info[idx].size, flags, 0,
@@ -1185,30 +1182,22 @@ new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags)
 void __init create_kmalloc_caches(slab_flags_t flags)
 {
 	int i;
-	enum kmalloc_cache_type type;
 
-	for (type = KMALLOC_NORMAL; type <= KMALLOC_RECLAIM; type++) {
-		for (i = 0; i < KMALLOC_CACHE_NUM; i++) {
-			if (!kmalloc_caches[type][i])
-				new_kmalloc_cache(i, type, flags);
-		}
-	}
+	for (i = 0; i < KMALLOC_CACHE_NUM; i++) {
+		if (!kmalloc_caches[KMALLOC_NORMAL][i])
+			new_kmalloc_cache(i, KMALLOC_NORMAL, flags);
 
-	/* Kmalloc array is now usable */
-	slab_state = UP;
+		new_kmalloc_cache(i, KMALLOC_RECLAIM,
+					flags | SLAB_RECLAIM_ACCOUNT);
 
 #ifdef CONFIG_ZONE_DMA
-	for (i = 0; i < KMALLOC_CACHE_NUM; i++) {
-		struct kmem_cache *s = kmalloc_caches[KMALLOC_NORMAL][i];
-
-		if (s) {
-			kmalloc_caches[KMALLOC_DMA][i] = create_kmalloc_cache(
-				kmalloc_info[i].name[KMALLOC_DMA],
-				kmalloc_info[i].size,
-				SLAB_CACHE_DMA | flags, 0, 0);
-		}
-	}
+		new_kmalloc_cache(i, KMALLOC_DMA,
+					flags | SLAB_CACHE_DMA);
 #endif
+	}
+
+	/* Kmalloc array is now usable */
+	slab_state = UP;
 }
 #endif /* !CONFIG_SLOB */
 
Signature · 1 line
2.21.0
author
#11 lore raw

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

In reply to Pengfei Li

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%
---
 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(-)
include/linux/slab.h +3 -3
index f53bb6980110..0842db5f7053 100644
@@ -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
mm/slab.c +2 -2
index 7bc4e90e1147..079c3e6ced1f 100644
@@ -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);
 		}
 	}
mm/slab_common.c +4 -4
index e7903bd28b1f..0f465eae32f6 100644
@@ -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,
mm/slub.c +6 -6
index 0e92ebdcacc9..e87243a16768 100644
@@ -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
Signature · 1 line
2.21.0
author
#12 lore raw

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

In reply to Pengfei Li

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%
---
 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(-)
include/linux/slab.h +3 -3
index f53bb6980110..0842db5f7053 100644
@@ -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
mm/slab.c +2 -2
index 7bc4e90e1147..079c3e6ced1f 100644
@@ -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);
 		}
 	}
mm/slab_common.c +4 -4
index e7903bd28b1f..0f465eae32f6 100644
@@ -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,
mm/slub.c +6 -6
index 0e92ebdcacc9..e87243a16768 100644
@@ -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
Signature · 1 line
2.21.0