b3ad832d8d
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 <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Ben Gainey <ben.gainey@arm.com>
Cc: Changbin Du <changbin.du@huawei.com>
Cc: Chengen Du <chengen.du@canonical.com>
Cc: Colin Ian King <colin.i.king@gmail.com>
Cc: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: K Prateek Nayak <kprateek.nayak@amd.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Li Dong <lidong@vivo.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Markus Elfring <Markus.Elfring@web.de>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paran Lee <p4ranlee@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Song Liu <song@kernel.org>
Cc: Sun Haiyong <sunhaiyong@loongson.cn>
Cc: Yanteng Si <siyanteng@loongson.cn>
Cc: zhaimingbing <zhaimingbing@cmss.chinamobile.com>
Link: https://lore.kernel.org/r/20240321160300.1635121-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.