[PATCH v2 0/4] mm, slab: Make kmalloc_info[] contain all types of names

[PATCH v2 0/4] mm, slab: Make kmalloc_info[] contain all types of names

[Pengfei Li]

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.

The other 4 patches did some cleanup work.

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()
5.3-rc7                       66264
5.3-rc7+patch                 42188

Pengfei Li (4):
  mm, slab: Make kmalloc_info[] contain all types of names
  mm, slab: Remove unused kmalloc_size()
  mm, slab_common: Make 'type' is enum kmalloc_cache_type
  mm, slab_common: Make initializing KMALLOC_DMA start from 1

 include/linux/slab.h |  20 ---------
 mm/slab.c            |   7 +--
 mm/slab.h            |   2 +-
 mm/slab_common.c     | 103 +++++++++++++++++++++++--------------------
 4 files changed, 60 insertions(+), 72 deletions(-)

-- 
2.21.0

[PATCH v2 1/4] mm, slab: Make kmalloc_info[] contain all types of names

[Pengfei Li]

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.

Signed-off-by: Pengfei Li <lpf.vector@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slab.c        |  2 +-
 mm/slab.h        |  2 +-
 mm/slab_common.c | 93 ++++++++++++++++++++++++++----------------------
 3 files changed, 52 insertions(+), 45 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index 9df370558e5d..c42b6211f42e 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -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;
diff --git a/mm/slab.h b/mm/slab.h
index 9057b8056b07..2fc8f956906a 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -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[];
 
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 807490fe217a..61c1e2e54263 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1092,26 +1092,56 @@ struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags)
 	return kmalloc_caches[kmalloc_type(flags)][index];
 }
 
+#ifdef CONFIG_ZONE_DMA
+#define SET_KMALLOC_SIZE(__size, __short_size)			\
+{								\
+	.name[KMALLOC_NORMAL]  = "kmalloc-" #__short_size,	\
+	.name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #__short_size,	\
+	.name[KMALLOC_DMA]     = "dma-kmalloc-" #__short_size,	\
+	.size = __size,						\
+}
+#else
+#define SET_KMALLOC_SIZE(__size, __short_size)			\
+{								\
+	.name[KMALLOC_NORMAL]  = "kmalloc-" #__short_size,	\
+	.name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #__short_size,	\
+	.size = __size,						\
+}
+#endif
+
 /*
  * kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time.
  * kmalloc_index() supports up to 2^26=64MB, so the final entry of the table is
  * kmalloc-67108864.
  */
-const struct kmalloc_info_struct kmalloc_info[] __initconst = {
-	{NULL,                      0},		{"kmalloc-96",             96},
-	{"kmalloc-192",           192},		{"kmalloc-8",               8},
-	{"kmalloc-16",             16},		{"kmalloc-32",             32},
-	{"kmalloc-64",             64},		{"kmalloc-128",           128},
-	{"kmalloc-256",           256},		{"kmalloc-512",           512},
-	{"kmalloc-1k",           1024},		{"kmalloc-2k",           2048},
-	{"kmalloc-4k",           4096},		{"kmalloc-8k",           8192},
-	{"kmalloc-16k",         16384},		{"kmalloc-32k",         32768},
-	{"kmalloc-64k",         65536},		{"kmalloc-128k",       131072},
-	{"kmalloc-256k",       262144},		{"kmalloc-512k",       524288},
-	{"kmalloc-1M",        1048576},		{"kmalloc-2M",        2097152},
-	{"kmalloc-4M",        4194304},		{"kmalloc-8M",        8388608},
-	{"kmalloc-16M",      16777216},		{"kmalloc-32M",      33554432},
-	{"kmalloc-64M",      67108864}
+const struct kmalloc_info_struct kmalloc_info[] = {
+	SET_KMALLOC_SIZE(0, 0),
+	SET_KMALLOC_SIZE(96, 96),
+	SET_KMALLOC_SIZE(192, 192),
+	SET_KMALLOC_SIZE(8, 8),
+	SET_KMALLOC_SIZE(16, 16),
+	SET_KMALLOC_SIZE(32, 32),
+	SET_KMALLOC_SIZE(64, 64),
+	SET_KMALLOC_SIZE(128, 128),
+	SET_KMALLOC_SIZE(256, 256),
+	SET_KMALLOC_SIZE(512, 512),
+	SET_KMALLOC_SIZE(1024, 1k),
+	SET_KMALLOC_SIZE(2048, 2k),
+	SET_KMALLOC_SIZE(4096, 4k),
+	SET_KMALLOC_SIZE(8192, 8k),
+	SET_KMALLOC_SIZE(16384, 16k),
+	SET_KMALLOC_SIZE(32768, 32k),
+	SET_KMALLOC_SIZE(65536, 64k),
+	SET_KMALLOC_SIZE(131072, 128k),
+	SET_KMALLOC_SIZE(262144, 256k),
+	SET_KMALLOC_SIZE(524288, 512k),
+	SET_KMALLOC_SIZE(1048576, 1M),
+	SET_KMALLOC_SIZE(2097152, 2M),
+	SET_KMALLOC_SIZE(4194304, 4M),
+	SET_KMALLOC_SIZE(8388608, 8M),
+	SET_KMALLOC_SIZE(16777216, 16M),
+	SET_KMALLOC_SIZE(33554432, 32M),
+	SET_KMALLOC_SIZE(67108864, 64M)
 };
 
 /*
@@ -1161,36 +1191,14 @@ void __init setup_kmalloc_cache_index_table(void)
 	}
 }
 
-static const char *
-kmalloc_cache_name(const char *prefix, unsigned int size)
-{
-
-	static const char units[3] = "\0kM";
-	int idx = 0;
-
-	while (size >= 1024 && (size % 1024 == 0)) {
-		size /= 1024;
-		idx++;
-	}
-
-	return kasprintf(GFP_NOWAIT, "%s-%u%c", prefix, size, units[idx]);
-}
-
 static void __init
 new_kmalloc_cache(int idx, int type, slab_flags_t flags)
 {
-	const char *name;
-
-	if (type == KMALLOC_RECLAIM) {
+	if (type == KMALLOC_RECLAIM)
 		flags |= SLAB_RECLAIM_ACCOUNT;
-		name = kmalloc_cache_name("kmalloc-rcl",
-						kmalloc_info[idx].size);
-		BUG_ON(!name);
-	} else {
-		name = kmalloc_info[idx].name;
-	}
 
-	kmalloc_caches[type][idx] = create_kmalloc_cache(name,
+	kmalloc_caches[type][idx] = create_kmalloc_cache(
+					kmalloc_info[idx].name[type],
 					kmalloc_info[idx].size, flags, 0,
 					kmalloc_info[idx].size);
 }
@@ -1232,11 +1240,10 @@ void __init create_kmalloc_caches(slab_flags_t flags)
 
 		if (s) {
 			unsigned int size = kmalloc_size(i);
-			const char *n = kmalloc_cache_name("dma-kmalloc", size);
 
-			BUG_ON(!n);
 			kmalloc_caches[KMALLOC_DMA][i] = create_kmalloc_cache(
-				n, size, SLAB_CACHE_DMA | flags, 0, 0);
+				kmalloc_info[i].name[KMALLOC_DMA],
+				size, SLAB_CACHE_DMA | flags, 0, 0);
 		}
 	}
 #endif
-- 
2.21.0

[PATCH v2 2/4] mm, slab: Remove unused kmalloc_size()

[Pengfei Li]

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

Signed-off-by: Pengfei Li <lpf.vector@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---
 include/linux/slab.h | 20 --------------------
 mm/slab.c            |  5 +++--
 mm/slab_common.c     |  5 ++---
 3 files changed, 5 insertions(+), 25 deletions(-)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index 56c9c7eed34e..e773e5764b7b 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -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
diff --git a/mm/slab.c b/mm/slab.c
index c42b6211f42e..7bc4e90e1147 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -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();
 
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 61c1e2e54263..cae27210e4c3 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -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
-- 
2.21.0

[PATCH v2 3/4] mm, slab_common: Make 'type' is enum kmalloc_cache_type

[Pengfei Li]

The 'type' of the function new_kmalloc_cache should be
enum kmalloc_cache_type instead of int, so correct it.

Signed-off-by: Pengfei Li <lpf.vector@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/slab_common.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/mm/slab_common.c b/mm/slab_common.c
index cae27210e4c3..d64a64660f86 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -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++) {
-- 
2.21.0

Re: [PATCH v2 3/4] mm, slab_common: Make 'type' is enum kmalloc_cache_type

[Roman Gushchin]

On Tue, Sep 10, 2019 at 01:07:14AM +0800, Pengfei Li wrote:

Hi Pengfei!

> The 'type' of the function new_kmalloc_cache should be
> enum kmalloc_cache_type instead of int, so correct it.

I think you mean type of the 'i' variable, not the type of
new_kmalloc_cache() function. Also the name of the patch is
misleading. How about
mm, slab_common: use enum kmalloc_cache_type to iterate over kmalloc caches ?
Or something like this.

The rest of the series looks good to me.

Please, feel free to use
Acked-by: Roman Gushchin <guro@fb.com>
for patches [1-3] in the series after fixing this commit message and
restoring __initconst.

Patch [4] needs some additional clarifications, IMO.

Thank you!

> 
> Signed-off-by: Pengfei Li <lpf.vector@gmail.com>
> Acked-by: Vlastimil Babka <vbabka@suse.cz>



> ---
>  mm/slab_common.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index cae27210e4c3..d64a64660f86 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -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++) {
> -- 
> 2.21.0
> 
> 

Re: [PATCH v2 3/4] mm, slab_common: Make 'type' is enum kmalloc_cache_type

[Pengfei Li]

On Tue, Sep 10, 2019 at 4:00 AM Roman Gushchin <guro@fb.com> wrote:
>
> On Tue, Sep 10, 2019 at 01:07:14AM +0800, Pengfei Li wrote:
>
> Hi Pengfei!
>
> > The 'type' of the function new_kmalloc_cache should be
> > enum kmalloc_cache_type instead of int, so correct it.
>
> I think you mean type of the 'i' variable, not the type of
> new_kmalloc_cache() function. Also the name of the patch is
> misleading. How about
> mm, slab_common: use enum kmalloc_cache_type to iterate over kmalloc caches ?
> Or something like this.
>

Ok, this name is really better :)

> The rest of the series looks good to me.
>
> Please, feel free to use
> Acked-by: Roman Gushchin <guro@fb.com>
> for patches [1-3] in the series after fixing this commit message and
> restoring __initconst.
>

Thanks!

> Patch [4] needs some additional clarifications, IMO.
>

I will add more clarification in v3.

> Thank you!
>
> >
> > Signed-off-by: Pengfei Li <lpf.vector@gmail.com>
> > Acked-by: Vlastimil Babka <vbabka@suse.cz>
>
>
>
> > ---
> >  mm/slab_common.c | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/mm/slab_common.c b/mm/slab_common.c
> > index cae27210e4c3..d64a64660f86 100644
> > --- a/mm/slab_common.c
> > +++ b/mm/slab_common.c
> > @@ -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++) {
> > --
> > 2.21.0
> >
> >

[PATCH v2 4/4] mm, slab_common: Make initializing KMALLOC_DMA start from 1

[Pengfei Li]

kmalloc_caches[KMALLOC_NORMAL][0] will never be initialized,
so the loop should start at 1 instead of 0

Signed-off-by: Pengfei Li <lpf.vector@gmail.com>
---
 mm/slab_common.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/slab_common.c b/mm/slab_common.c
index d64a64660f86..6b3e526934d9 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1236,7 +1236,7 @@ void __init create_kmalloc_caches(slab_flags_t flags)
 	slab_state = UP;
 
 #ifdef CONFIG_ZONE_DMA
-	for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) {
+	for (i = 1; i <= KMALLOC_SHIFT_HIGH; i++) {
 		struct kmem_cache *s = kmalloc_caches[KMALLOC_NORMAL][i];
 
 		if (s) {
-- 
2.21.0