perf dso: Reorder members to save space in 'struct dso'

Save 40 bytes and move from 8 to 7 cache lines. Make member dwfl
dependent on being a powerpc build. Squeeze bits of int/enum types
when appropriate. Remove holes/padding by reordering variables.

Before:

struct dso {
struct mutex lock; /* 0 40 */
struct list_head node; /* 40 16 */
struct rb_node rb_node __attribute__((__aligned__(8))); /* 56 24 */
/* --- cacheline 1 boundary (64 bytes) was 16 bytes ago --- */
struct rb_root * root; /* 80 8 */
struct rb_root_cached symbols; /* 88 16 */
struct symbol * * symbol_names; /* 104 8 */
size_t symbol_names_len; /* 112 8 */
struct rb_root_cached inlined_nodes; /* 120 16 */
/* --- cacheline 2 boundary (128 bytes) was 8 bytes ago --- */
struct rb_root_cached srclines; /* 136 16 */
struct {
u64 addr; /* 152 8 */
struct symbol * symbol; /* 160 8 */
} last_find_result; /* 152 16 */
void * a2l; /* 168 8 */
char * symsrc_filename; /* 176 8 */
unsigned int a2l_fails; /* 184 4 */
enum dso_space_type kernel; /* 188 4 */
/* --- cacheline 3 boundary (192 bytes) --- */
_Bool is_kmod; /* 192 1 */

/* XXX 3 bytes hole, try to pack */

enum dso_swap_type needs_swap; /* 196 4 */
enum dso_binary_type symtab_type; /* 200 4 */
enum dso_binary_type binary_type; /* 204 4 */
enum dso_load_errno load_errno; /* 208 4 */
u8 adjust_symbols:1; /* 212: 0 1 */
u8 has_build_id:1; /* 212: 1 1 */
u8 header_build_id:1; /* 212: 2 1 */
u8 has_srcline:1; /* 212: 3 1 */
u8 hit:1; /* 212: 4 1 */
u8 annotate_warned:1; /* 212: 5 1 */
u8 auxtrace_warned:1; /* 212: 6 1 */
u8 short_name_allocated:1; /* 212: 7 1 */
u8 long_name_allocated:1; /* 213: 0 1 */
u8 is_64_bit:1; /* 213: 1 1 */

/* XXX 6 bits hole, try to pack */

_Bool sorted_by_name; /* 214 1 */
_Bool loaded; /* 215 1 */
u8 rel; /* 216 1 */

/* XXX 7 bytes hole, try to pack */

struct build_id bid; /* 224 32 */
/* --- cacheline 4 boundary (256 bytes) --- */
u64 text_offset; /* 256 8 */
u64 text_end; /* 264 8 */
const char * short_name; /* 272 8 */
const char * long_name; /* 280 8 */
u16 long_name_len; /* 288 2 */
u16 short_name_len; /* 290 2 */

/* XXX 4 bytes hole, try to pack */

void * dwfl; /* 296 8 */
struct auxtrace_cache * auxtrace_cache; /* 304 8 */
int comp; /* 312 4 */

/* XXX 4 bytes hole, try to pack */

/* --- cacheline 5 boundary (320 bytes) --- */
struct {
struct rb_root cache; /* 320 8 */
int fd; /* 328 4 */
int status; /* 332 4 */
u32 status_seen; /* 336 4 */

/* XXX 4 bytes hole, try to pack */

u64 file_size; /* 344 8 */
struct list_head open_entry; /* 352 16 */
u64 elf_base_addr; /* 368 8 */
u64 debug_frame_offset; /* 376 8 */
/* --- cacheline 6 boundary (384 bytes) --- */
u64 eh_frame_hdr_addr; /* 384 8 */
u64 eh_frame_hdr_offset; /* 392 8 */
} data; /* 320 80 */
struct {
u32 id; /* 400 4 */
u32 sub_id; /* 404 4 */
struct perf_env * env; /* 408 8 */
} bpf_prog; /* 400 16 */
union {
void * priv; /* 416 8 */
u64 db_id; /* 416 8 */
}; /* 416 8 */
struct nsinfo * nsinfo; /* 424 8 */
struct dso_id id; /* 432 24 */
/* --- cacheline 7 boundary (448 bytes) was 8 bytes ago --- */
refcount_t refcnt; /* 456 4 */
char name[]; /* 460 0 */

/* size: 464, cachelines: 8, members: 49 */
/* sum members: 440, holes: 4, sum holes: 18 */
/* sum bitfield members: 10 bits, bit holes: 1, sum bit holes: 6 bits */
/* padding: 4 */
/* forced alignments: 1 */
/* last cacheline: 16 bytes */
} __attribute__((__aligned__(8)));

After:

struct dso {
struct mutex lock; /* 0 40 */
struct list_head node; /* 40 16 */
struct rb_node rb_node __attribute__((__aligned__(8))); /* 56 24 */
/* --- cacheline 1 boundary (64 bytes) was 16 bytes ago --- */
struct rb_root * root; /* 80 8 */
struct rb_root_cached symbols; /* 88 16 */
struct symbol * * symbol_names; /* 104 8 */
size_t symbol_names_len; /* 112 8 */
struct rb_root_cached inlined_nodes; /* 120 16 */
/* --- cacheline 2 boundary (128 bytes) was 8 bytes ago --- */
struct rb_root_cached srclines; /* 136 16 */
struct {
u64 addr; /* 152 8 */
struct symbol * symbol; /* 160 8 */
} last_find_result; /* 152 16 */
struct build_id bid; /* 168 32 */
/* --- cacheline 3 boundary (192 bytes) was 8 bytes ago --- */
u64 text_offset; /* 200 8 */
u64 text_end; /* 208 8 */
const char * short_name; /* 216 8 */
const char * long_name; /* 224 8 */
void * a2l; /* 232 8 */
char * symsrc_filename; /* 240 8 */
struct nsinfo * nsinfo; /* 248 8 */
/* --- cacheline 4 boundary (256 bytes) --- */
struct auxtrace_cache * auxtrace_cache; /* 256 8 */
union {
void * priv; /* 264 8 */
u64 db_id; /* 264 8 */
}; /* 264 8 */
struct {
struct perf_env * env; /* 272 8 */
u32 id; /* 280 4 */
u32 sub_id; /* 284 4 */
} bpf_prog; /* 272 16 */
struct {
struct rb_root cache; /* 288 8 */
struct list_head open_entry; /* 296 16 */
u64 file_size; /* 312 8 */
/* --- cacheline 5 boundary (320 bytes) --- */
u64 elf_base_addr; /* 320 8 */
u64 debug_frame_offset; /* 328 8 */
u64 eh_frame_hdr_addr; /* 336 8 */
u64 eh_frame_hdr_offset; /* 344 8 */
int fd; /* 352 4 */
int status; /* 356 4 */
u32 status_seen; /* 360 4 */
} data; /* 288 80 */

/* XXX last struct has 4 bytes of padding */

struct dso_id id; /* 368 24 */
/* --- cacheline 6 boundary (384 bytes) was 8 bytes ago --- */
unsigned int a2l_fails; /* 392 4 */
int comp; /* 396 4 */
refcount_t refcnt; /* 400 4 */
enum dso_load_errno load_errno; /* 404 4 */
u16 long_name_len; /* 408 2 */
u16 short_name_len; /* 410 2 */
enum dso_binary_type symtab_type:8; /* 412: 0 4 */
enum dso_binary_type binary_type:8; /* 412: 8 4 */
enum dso_space_type kernel:2; /* 412:16 4 */
enum dso_swap_type needs_swap:2; /* 412:18 4 */

/* Bitfield combined with next fields */

_Bool is_kmod:1; /* 414: 4 1 */
u8 adjust_symbols:1; /* 414: 5 1 */
u8 has_build_id:1; /* 414: 6 1 */
u8 header_build_id:1; /* 414: 7 1 */
u8 has_srcline:1; /* 415: 0 1 */
u8 hit:1; /* 415: 1 1 */
u8 annotate_warned:1; /* 415: 2 1 */
u8 auxtrace_warned:1; /* 415: 3 1 */
u8 short_name_allocated:1; /* 415: 4 1 */
u8 long_name_allocated:1; /* 415: 5 1 */
u8 is_64_bit:1; /* 415: 6 1 */

/* XXX 1 bit hole, try to pack */

_Bool sorted_by_name; /* 416 1 */
_Bool loaded; /* 417 1 */
u8 rel; /* 418 1 */
char name[]; /* 419 0 */

/* size: 424, cachelines: 7, members: 48 */
/* sum members: 415 */
/* sum bitfield members: 31 bits, bit holes: 1, sum bit holes: 1 bits */
/* padding: 5 */
/* paddings: 1, sum paddings: 4 */
/* forced alignments: 1 */
/* last cacheline: 40 bytes */
} __attribute__((__aligned__(8)));

Signed-off-by: Ian Rogers <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: Ahelenia Ziemiańska <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Andi Kleen <[e-mail]>
Cc: Athira Rajeev <[e-mail]>
Cc: Ben Gainey <[e-mail]>
Cc: Changbin Du <[e-mail]>
Cc: Chengen Du <[e-mail]>
Cc: Colin Ian King <[e-mail]>
Cc: Ilkka Koskinen <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: James Clark <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: K Prateek Nayak <[e-mail]>
Cc: Kan Liang <[e-mail]>
Cc: Leo Yan <[e-mail]>
Cc: Li Dong <[e-mail]>
Cc: Liam Howlett <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Markus Elfring <[e-mail]>
Cc: Masami Hiramatsu <[e-mail]>
Cc: Miguel Ojeda <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Paran Lee <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Ravi Bangoria <[e-mail]>
Cc: Song Liu <[e-mail]>
Cc: Sun Haiyong <[e-mail]>
Cc: Yanteng Si <[e-mail]>
Cc: zhaimingbing <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/dso.h

···
 		u64		addr;
 		struct symbol	*symbol;
 	} last_find_result;
+	struct build_id	 bid;
+	u64		 text_offset;
+	u64		 text_end;
+	const char	 *short_name;
+	const char	 *long_name;
 	void		 *a2l;
 	char		 *symsrc_filename;
+#if defined(__powerpc__)
+	void		*dwfl;			/* DWARF debug info */
+#endif
+	struct nsinfo	*nsinfo;
+	struct auxtrace_cache *auxtrace_cache;
+	union { /* Tool specific area */
+		void	 *priv;
+		u64	 db_id;
+	};
+	/* bpf prog information */
+	struct {
+		struct perf_env	*env;
+		u32		id;
+		u32		sub_id;
+	} bpf_prog;
+	/* dso data file */
+	struct {
+		struct rb_root	 cache;
+		struct list_head open_entry;
+		u64		 file_size;
+		u64		 elf_base_addr;
+		u64		 debug_frame_offset;
+		u64		 eh_frame_hdr_addr;
+		u64		 eh_frame_hdr_offset;
+		int		 fd;
+		int		 status;
+		u32		 status_seen;
+	} data;
+	struct dso_id	 id;
 	unsigned int	 a2l_fails;
-	enum dso_space_type	kernel;
-	bool			is_kmod;
-	enum dso_swap_type	needs_swap;
-	enum dso_binary_type	symtab_type;
-	enum dso_binary_type	binary_type;
+	int		 comp;
+	refcount_t	 refcnt;
 	enum dso_load_errno	load_errno;
+	u16		 long_name_len;
+	u16		 short_name_len;
+	enum dso_binary_type	symtab_type:8;
+	enum dso_binary_type	binary_type:8;
+	enum dso_space_type	kernel:2;
+	enum dso_swap_type	needs_swap:2;
+	bool			is_kmod:1;
 	u8		 adjust_symbols:1;
 	u8		 has_build_id:1;
 	u8		 header_build_id:1;
···
 	bool		 sorted_by_name;
 	bool		 loaded;
 	u8		 rel;
-	struct build_id	 bid;
-	u64		 text_offset;
-	u64		 text_end;
-	const char	 *short_name;
-	const char	 *long_name;
-	u16		 long_name_len;
-	u16		 short_name_len;
-	void		*dwfl;			/* DWARF debug info */
-	struct auxtrace_cache *auxtrace_cache;
-	int		 comp;
-
-	/* dso data file */
-	struct {
-		struct rb_root	 cache;
-		int		 fd;
-		int		 status;
-		u32		 status_seen;
-		u64		 file_size;
-		struct list_head open_entry;
-		u64		 elf_base_addr;
-		u64		 debug_frame_offset;
-		u64		 eh_frame_hdr_addr;
-		u64		 eh_frame_hdr_offset;
-	} data;
-	/* bpf prog information */
-	struct {
-		u32		id;
-		u32		sub_id;
-		struct perf_env	*env;
-	} bpf_prog;
-
-	union { /* Tool specific area */
-		void	 *priv;
-		u64	 db_id;
-	};
-	struct nsinfo	*nsinfo;
-	struct dso_id	 id;
-	refcount_t	 refcnt;
 	char		 name[];
 };