diff mbox series

[v2,bpf-next] bpf: select proper size for bpf_prog_pack

Message ID 20220308195303.556765-1-song@kernel.org (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series [v2,bpf-next] bpf: select proper size for bpf_prog_pack | expand

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Context Check Description
netdev/tree_selection success Clearly marked for bpf-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Single patches do not need cover letters
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 9 this patch: 9
netdev/cc_maintainers fail 1 blamed authors not CCed: songliubraving@fb.com; 5 maintainers not CCed: kpsingh@kernel.org john.fastabend@gmail.com kafai@fb.com songliubraving@fb.com yhs@fb.com
netdev/build_clang success Errors and warnings before: 18 this patch: 18
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 14 this patch: 14
netdev/checkpatch warning WARNING: line length of 88 exceeds 80 columns WARNING: line length of 89 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next-PR success PR summary
bpf/vmtest-bpf-next success VM_Test

Commit Message

Song Liu March 8, 2022, 7:53 p.m. UTC 
Using HPAGE_PMD_SIZE as the size for bpf_prog_pack is not ideal in some
cases. Specifically, for NUMA systems, __vmalloc_node_range requires
PMD_SIZE * num_online_nodes() to allocate huge pages. Also, if the system
does not support huge pages (i.e., with cmdline option nohugevmalloc), it
is better to use PAGE_SIZE packs.

Add logic to select proper size for bpf_prog_pack. This solution is not
ideal, as it makes assumption about the behavior of module_alloc and
__vmalloc_node_range. However, it appears to be the easiest solution as
it doesn't require changes in module_alloc and vmalloc code.

Fixes: 57631054fae6 ("bpf: Introduce bpf_prog_pack allocator")
Signed-off-by: Song Liu <song@kernel.org>

---
Changes v1 => v2:
1. Fix case with first program > PAGE_SIZE. (Daniel)
2. Add Fixes tag.
3. Remove a inline to avoid netdev/source_inline error.
---
 kernel/bpf/core.c | 75 ++++++++++++++++++++++++++++++++---------------
 1 file changed, 51 insertions(+), 24 deletions(-)

Comments

Song Liu March 9, 2022, 6:04 p.m. UTC | #1 
> On Mar 8, 2022, at 11:53 AM, Song Liu <song@kernel.org> wrote:
> 
> Using HPAGE_PMD_SIZE as the size for bpf_prog_pack is not ideal in some
> cases. Specifically, for NUMA systems, __vmalloc_node_range requires
> PMD_SIZE * num_online_nodes() to allocate huge pages. Also, if the system
> does not support huge pages (i.e., with cmdline option nohugevmalloc), it
> is better to use PAGE_SIZE packs.
> 
> Add logic to select proper size for bpf_prog_pack. This solution is not
> ideal, as it makes assumption about the behavior of module_alloc and
> __vmalloc_node_range. However, it appears to be the easiest solution as
> it doesn't require changes in module_alloc and vmalloc code.
> 
> Fixes: 57631054fae6 ("bpf: Introduce bpf_prog_pack allocator")
> Signed-off-by: Song Liu <song@kernel.org>

I messed something up... Please ignore this version. I will send v3
soon. 

Song

> 
> ---
> Changes v1 => v2:
> 1. Fix case with first program > PAGE_SIZE. (Daniel)
> 2. Add Fixes tag.
> 3. Remove a inline to avoid netdev/source_inline error.
> ---
> kernel/bpf/core.c | 75 ++++++++++++++++++++++++++++++++---------------
> 1 file changed, 51 insertions(+), 24 deletions(-)
> 
> diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
> index ab630f773ec1..f039c1f7e5dd 100644
> --- a/kernel/bpf/core.c
> +++ b/kernel/bpf/core.c
> @@ -33,6 +33,7 @@
> #include <linux/extable.h>
> #include <linux/log2.h>
> #include <linux/bpf_verifier.h>
> +#include <linux/nodemask.h>
> 
> #include <asm/barrier.h>
> #include <asm/unaligned.h>
> @@ -814,15 +815,9 @@ int bpf_jit_add_poke_descriptor(struct bpf_prog *prog,
>  * allocator. The prog_pack allocator uses HPAGE_PMD_SIZE page (2MB on x86)
>  * to host BPF programs.
>  */
> -#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> -#define BPF_PROG_PACK_SIZE	HPAGE_PMD_SIZE
> -#else
> -#define BPF_PROG_PACK_SIZE	PAGE_SIZE
> -#endif
> #define BPF_PROG_CHUNK_SHIFT	6
> #define BPF_PROG_CHUNK_SIZE	(1 << BPF_PROG_CHUNK_SHIFT)
> #define BPF_PROG_CHUNK_MASK	(~(BPF_PROG_CHUNK_SIZE - 1))
> -#define BPF_PROG_CHUNK_COUNT	(BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE)
> 
> struct bpf_prog_pack {
> 	struct list_head list;
> @@ -830,30 +825,59 @@ struct bpf_prog_pack {
> 	unsigned long bitmap[];
> };
> 
> -#define BPF_PROG_MAX_PACK_PROG_SIZE	BPF_PROG_PACK_SIZE
> #define BPF_PROG_SIZE_TO_NBITS(size)	(round_up(size, BPF_PROG_CHUNK_SIZE) / BPF_PROG_CHUNK_SIZE)
> 
> +static size_t bpf_prog_pack_size = -1;
> +
> +static int bpf_prog_chunk_count(void)
> +{
> +	WARN_ON_ONCE(bpf_prog_pack_size == -1);
> +	return bpf_prog_pack_size / BPF_PROG_CHUNK_SIZE;
> +}
> +
> static DEFINE_MUTEX(pack_mutex);
> static LIST_HEAD(pack_list);
> 
> +static size_t select_bpf_prog_pack_size(void)
> +{
> +	size_t size;
> +	void *ptr;
> +
> +	size = PMD_SIZE * num_online_nodes() - 1;
> +	ptr = module_alloc(size);
> +
> +	/* Test whether we can get huge pages. If not just use PAGE_SIZE
> +	 * packs.
> +	 */
> +	if (!ptr || !is_vm_area_hugepages(ptr))
> +		size = PAGE_SIZE;
> +
> +	vfree(ptr);
> +	return size;
> +}
> +
> static struct bpf_prog_pack *alloc_new_pack(void)
> {
> 	struct bpf_prog_pack *pack;
> +	void *ptr;
> 
> -	pack = kzalloc(sizeof(*pack) + BITS_TO_BYTES(BPF_PROG_CHUNK_COUNT), GFP_KERNEL);
> -	if (!pack)
> +	ptr = module_alloc(bpf_prog_pack_size);
> +	if (!ptr)
> 		return NULL;
> -	pack->ptr = module_alloc(BPF_PROG_PACK_SIZE);
> -	if (!pack->ptr) {
> -		kfree(pack);
> +
> +	pack = kzalloc(struct_size(pack, bitmap, BITS_TO_LONGS(bpf_prog_chunk_count())),
> +		       GFP_KERNEL);
> +	if (!pack) {
> +		vfree(ptr);
> 		return NULL;
> 	}
> -	bitmap_zero(pack->bitmap, BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE);
> +	pack->ptr = ptr;
> +	bitmap_zero(pack->bitmap, bpf_prog_pack_size / BPF_PROG_CHUNK_SIZE);
> 	list_add_tail(&pack->list, &pack_list);
> 
> 	set_vm_flush_reset_perms(pack->ptr);
> -	set_memory_ro((unsigned long)pack->ptr, BPF_PROG_PACK_SIZE / PAGE_SIZE);
> -	set_memory_x((unsigned long)pack->ptr, BPF_PROG_PACK_SIZE / PAGE_SIZE);
> +	set_memory_ro((unsigned long)pack->ptr, bpf_prog_pack_size / PAGE_SIZE);
> +	set_memory_x((unsigned long)pack->ptr, bpf_prog_pack_size / PAGE_SIZE);
> 	return pack;
> }
> 
> @@ -864,7 +888,11 @@ static void *bpf_prog_pack_alloc(u32 size)
> 	unsigned long pos;
> 	void *ptr = NULL;
> 
> -	if (size > BPF_PROG_MAX_PACK_PROG_SIZE) {
> +	mutex_lock(&pack_mutex);
> +	if (bpf_prog_pack_size == -1)
> +		bpf_prog_pack_size = select_bpf_prog_pack_size();
> +
> +	if (size > bpf_prog_pack_size) {
> 		size = round_up(size, PAGE_SIZE);
> 		ptr = module_alloc(size);
> 		if (ptr) {
> @@ -872,13 +900,12 @@ static void *bpf_prog_pack_alloc(u32 size)
> 			set_memory_ro((unsigned long)ptr, size / PAGE_SIZE);
> 			set_memory_x((unsigned long)ptr, size / PAGE_SIZE);
> 		}
> -		return ptr;
> +		goto out;
> 	}
> -	mutex_lock(&pack_mutex);
> 	list_for_each_entry(pack, &pack_list, list) {
> -		pos = bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0,
> +		pos = bitmap_find_next_zero_area(pack->bitmap, bpf_prog_chunk_count(), 0,
> 						 nbits, 0);
> -		if (pos < BPF_PROG_CHUNK_COUNT)
> +		if (pos < bpf_prog_chunk_count())
> 			goto found_free_area;
> 	}
> 
> @@ -904,12 +931,12 @@ static void bpf_prog_pack_free(struct bpf_binary_header *hdr)
> 	unsigned long pos;
> 	void *pack_ptr;
> 
> -	if (hdr->size > BPF_PROG_MAX_PACK_PROG_SIZE) {
> +	if (hdr->size > bpf_prog_pack_size) {
> 		module_memfree(hdr);
> 		return;
> 	}
> 
> -	pack_ptr = (void *)((unsigned long)hdr & ~(BPF_PROG_PACK_SIZE - 1));
> +	pack_ptr = (void *)((unsigned long)hdr & ~(bpf_prog_pack_size - 1));
> 	mutex_lock(&pack_mutex);
> 
> 	list_for_each_entry(tmp, &pack_list, list) {
> @@ -926,8 +953,8 @@ static void bpf_prog_pack_free(struct bpf_binary_header *hdr)
> 	pos = ((unsigned long)hdr - (unsigned long)pack_ptr) >> BPF_PROG_CHUNK_SHIFT;
> 
> 	bitmap_clear(pack->bitmap, pos, nbits);
> -	if (bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0,
> -				       BPF_PROG_CHUNK_COUNT, 0) == 0) {
> +	if (bitmap_find_next_zero_area(pack->bitmap, bpf_prog_chunk_count(), 0,
> +				       bpf_prog_chunk_count(), 0) == 0) {
> 		list_del(&pack->list);
> 		module_memfree(pack->ptr);
> 		kfree(pack);
> -- 
> 2.30.2
>
diff mbox series

Patch

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index ab630f773ec1..f039c1f7e5dd 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -33,6 +33,7 @@ 
 #include <linux/extable.h>
 #include <linux/log2.h>
 #include <linux/bpf_verifier.h>
+#include <linux/nodemask.h>
 
 #include <asm/barrier.h>
 #include <asm/unaligned.h>
@@ -814,15 +815,9 @@  int bpf_jit_add_poke_descriptor(struct bpf_prog *prog,
  * allocator. The prog_pack allocator uses HPAGE_PMD_SIZE page (2MB on x86)
  * to host BPF programs.
  */
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-#define BPF_PROG_PACK_SIZE	HPAGE_PMD_SIZE
-#else
-#define BPF_PROG_PACK_SIZE	PAGE_SIZE
-#endif
 #define BPF_PROG_CHUNK_SHIFT	6
 #define BPF_PROG_CHUNK_SIZE	(1 << BPF_PROG_CHUNK_SHIFT)
 #define BPF_PROG_CHUNK_MASK	(~(BPF_PROG_CHUNK_SIZE - 1))
-#define BPF_PROG_CHUNK_COUNT	(BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE)
 
 struct bpf_prog_pack {
 	struct list_head list;
@@ -830,30 +825,59 @@  struct bpf_prog_pack {
 	unsigned long bitmap[];
 };
 
-#define BPF_PROG_MAX_PACK_PROG_SIZE	BPF_PROG_PACK_SIZE
 #define BPF_PROG_SIZE_TO_NBITS(size)	(round_up(size, BPF_PROG_CHUNK_SIZE) / BPF_PROG_CHUNK_SIZE)
 
+static size_t bpf_prog_pack_size = -1;
+
+static int bpf_prog_chunk_count(void)
+{
+	WARN_ON_ONCE(bpf_prog_pack_size == -1);
+	return bpf_prog_pack_size / BPF_PROG_CHUNK_SIZE;
+}
+
 static DEFINE_MUTEX(pack_mutex);
 static LIST_HEAD(pack_list);
 
+static size_t select_bpf_prog_pack_size(void)
+{
+	size_t size;
+	void *ptr;
+
+	size = PMD_SIZE * num_online_nodes() - 1;
+	ptr = module_alloc(size);
+
+	/* Test whether we can get huge pages. If not just use PAGE_SIZE
+	 * packs.
+	 */
+	if (!ptr || !is_vm_area_hugepages(ptr))
+		size = PAGE_SIZE;
+
+	vfree(ptr);
+	return size;
+}
+
 static struct bpf_prog_pack *alloc_new_pack(void)
 {
 	struct bpf_prog_pack *pack;
+	void *ptr;
 
-	pack = kzalloc(sizeof(*pack) + BITS_TO_BYTES(BPF_PROG_CHUNK_COUNT), GFP_KERNEL);
-	if (!pack)
+	ptr = module_alloc(bpf_prog_pack_size);
+	if (!ptr)
 		return NULL;
-	pack->ptr = module_alloc(BPF_PROG_PACK_SIZE);
-	if (!pack->ptr) {
-		kfree(pack);
+
+	pack = kzalloc(struct_size(pack, bitmap, BITS_TO_LONGS(bpf_prog_chunk_count())),
+		       GFP_KERNEL);
+	if (!pack) {
+		vfree(ptr);
 		return NULL;
 	}
-	bitmap_zero(pack->bitmap, BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE);
+	pack->ptr = ptr;
+	bitmap_zero(pack->bitmap, bpf_prog_pack_size / BPF_PROG_CHUNK_SIZE);
 	list_add_tail(&pack->list, &pack_list);
 
 	set_vm_flush_reset_perms(pack->ptr);
-	set_memory_ro((unsigned long)pack->ptr, BPF_PROG_PACK_SIZE / PAGE_SIZE);
-	set_memory_x((unsigned long)pack->ptr, BPF_PROG_PACK_SIZE / PAGE_SIZE);
+	set_memory_ro((unsigned long)pack->ptr, bpf_prog_pack_size / PAGE_SIZE);
+	set_memory_x((unsigned long)pack->ptr, bpf_prog_pack_size / PAGE_SIZE);
 	return pack;
 }
 
@@ -864,7 +888,11 @@  static void *bpf_prog_pack_alloc(u32 size)
 	unsigned long pos;
 	void *ptr = NULL;
 
-	if (size > BPF_PROG_MAX_PACK_PROG_SIZE) {
+	mutex_lock(&pack_mutex);
+	if (bpf_prog_pack_size == -1)
+		bpf_prog_pack_size = select_bpf_prog_pack_size();
+
+	if (size > bpf_prog_pack_size) {
 		size = round_up(size, PAGE_SIZE);
 		ptr = module_alloc(size);
 		if (ptr) {
@@ -872,13 +900,12 @@  static void *bpf_prog_pack_alloc(u32 size)
 			set_memory_ro((unsigned long)ptr, size / PAGE_SIZE);
 			set_memory_x((unsigned long)ptr, size / PAGE_SIZE);
 		}
-		return ptr;
+		goto out;
 	}
-	mutex_lock(&pack_mutex);
 	list_for_each_entry(pack, &pack_list, list) {
-		pos = bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0,
+		pos = bitmap_find_next_zero_area(pack->bitmap, bpf_prog_chunk_count(), 0,
 						 nbits, 0);
-		if (pos < BPF_PROG_CHUNK_COUNT)
+		if (pos < bpf_prog_chunk_count())
 			goto found_free_area;
 	}
 
@@ -904,12 +931,12 @@  static void bpf_prog_pack_free(struct bpf_binary_header *hdr)
 	unsigned long pos;
 	void *pack_ptr;
 
-	if (hdr->size > BPF_PROG_MAX_PACK_PROG_SIZE) {
+	if (hdr->size > bpf_prog_pack_size) {
 		module_memfree(hdr);
 		return;
 	}
 
-	pack_ptr = (void *)((unsigned long)hdr & ~(BPF_PROG_PACK_SIZE - 1));
+	pack_ptr = (void *)((unsigned long)hdr & ~(bpf_prog_pack_size - 1));
 	mutex_lock(&pack_mutex);
 
 	list_for_each_entry(tmp, &pack_list, list) {
@@ -926,8 +953,8 @@  static void bpf_prog_pack_free(struct bpf_binary_header *hdr)
 	pos = ((unsigned long)hdr - (unsigned long)pack_ptr) >> BPF_PROG_CHUNK_SHIFT;
 
 	bitmap_clear(pack->bitmap, pos, nbits);
-	if (bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0,
-				       BPF_PROG_CHUNK_COUNT, 0) == 0) {
+	if (bitmap_find_next_zero_area(pack->bitmap, bpf_prog_chunk_count(), 0,
+				       bpf_prog_chunk_count(), 0) == 0) {
 		list_del(&pack->list);
 		module_memfree(pack->ptr);
 		kfree(pack);