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libbb: add and use infrastructure for fixed page size optimization

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function                                             old     new   delta
procps_scan                                         1121    1118      -3
getpagesize                                            6       -      -6
rpm_main                                            1037    1027     -10
rpm2cpio_main                                        120     110     -10
ptok                                                  38      21     -17
time_main                                           1282    1261     -21
mkswap_main                                          317     278     -39
------------------------------------------------------------------------------
(add/remove: 0/2 grow/shrink: 0/6 up/down: 0/-106)           Total: -106 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2020-12-14 18:49:23 +01:00
parent fd3c512f88
commit c7b858ff8d
7 changed files with 37 additions and 20 deletions
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10
archival/rpm.c
View File

@ -83,7 +83,9 @@ struct globals {
void *map;
rpm_index *mytags;
int tagcount;
unsigned mapsize, pagesize;
unsigned mapsize;
IF_VARIABLE_ARCH_PAGESIZE(unsigned pagesize;)
#define G_pagesize cached_pagesize(G.pagesize)
} FIX_ALIASING;
#define G (*(struct globals*)bb_common_bufsiz1)
#define INIT_G() do { setup_common_bufsiz(); } while (0)
@ -141,7 +143,7 @@ static int rpm_gettags(const char *filename)
G.mytags = tags;
/* Map the store */
storepos = (storepos + G.pagesize) & -(int)G.pagesize;
storepos = (storepos + G_pagesize) & -(int)G_pagesize;
/* remember size for munmap */
G.mapsize = storepos;
/* some NOMMU systems prefer MAP_PRIVATE over MAP_SHARED */
@ -356,7 +358,7 @@ int rpm_main(int argc, char **argv)
int opt, func = 0;
INIT_G();
G.pagesize = getpagesize();
INIT_PAGESIZE(G.pagesize);
while ((opt = getopt(argc, argv, "iqpldc")) != -1) {
switch (opt) {
@ -523,7 +525,7 @@ int rpm2cpio_main(int argc UNUSED_PARAM, char **argv)
int rpm_fd;
INIT_G();
G.pagesize = getpagesize();
INIT_PAGESIZE(G.pagesize);
rpm_fd = rpm_gettags(argv[1]);

18
include/libbb.h
View File

@ -391,6 +391,24 @@ void *mmap_read(int fd, size_t size) FAST_FUNC;
void *mmap_anon(size_t size) FAST_FUNC;
void *xmmap_anon(size_t size) FAST_FUNC;
#if defined(__x86_64__) || defined(i386)
# define BB_ARCH_FIXED_PAGESIZE 4096
#else /* if defined(ARCH) */
/* add you favorite arch today! */
#endif
#if defined BB_ARCH_FIXED_PAGESIZE
# define IF_VARIABLE_ARCH_PAGESIZE(...) /*nothing*/
# define bb_getpagesize() BB_ARCH_FIXED_PAGESIZE
# define INIT_PAGESIZE(var) ((void)0)
# define cached_pagesize(var) BB_ARCH_FIXED_PAGESIZE
#else
# define IF_VARIABLE_ARCH_PAGESIZE(...) __VA_ARGS__
# define bb_getpagesize() getpagesize()
# define INIT_PAGESIZE(var) ((var) = getpagesize())
# define cached_pagesize(var) (var)
#endif
//TODO: supply a pointer to char[11] buffer (avoid statics)?
extern const char *bb_mode_string(mode_t mode) FAST_FUNC;

4
libbb/procps.c
View File

@ -94,15 +94,15 @@ static int read_to_buf(const char *filename, void *buf)
static procps_status_t* FAST_FUNC alloc_procps_scan(void)
{
unsigned n = getpagesize();
procps_status_t* sp = xzalloc(sizeof(procps_status_t));
sp->dir = xopendir("/proc");
unsigned n = bb_getpagesize();
while (1) {
n >>= 1;
if (!n) break;
sp->shift_pages_to_bytes++;
}
sp->shift_pages_to_kb = sp->shift_pages_to_bytes - 10;
sp->dir = xopendir("/proc");
return sp;
}

2
miscutils/devmem.c
View File

@ -75,7 +75,7 @@ int devmem_main(int argc UNUSED_PARAM, char **argv)
bb_show_usage(); /* one of bb_strtouXX failed */
fd = xopen("/dev/mem", argv[3] ? (O_RDWR | O_SYNC) : (O_RDONLY | O_SYNC));
mapped_size = page_size = getpagesize();
mapped_size = page_size = bb_getpagesize();
offset_in_page = (unsigned)target & (page_size - 1);
if (offset_in_page + width > page_size) {
/* This access spans pages.

14
miscutils/hexedit.c
View File

@ -31,7 +31,8 @@ struct globals {
int fd;
unsigned height;
unsigned row;
unsigned pagesize;
IF_VARIABLE_ARCH_PAGESIZE(unsigned pagesize;)
#define G_pagesize cached_pagesize(G.pagesize)
uint8_t *baseaddr;
uint8_t *current_byte;
uint8_t *eof_byte;
@ -46,15 +47,6 @@ struct globals {
SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
} while (0)
//TODO: move to libbb
#if defined(__x86_64__) || defined(i386)
# define G_pagesize 4096
# define INIT_PAGESIZE() ((void)0)
#else
# define G_pagesize (G.pagesize)
# define INIT_PAGESIZE() ((void)(G.pagesize = getpagesize()))
#endif
/* hopefully there aren't arches with PAGE_SIZE > 64k */
#define G_mapsize (64*1024)
@ -262,7 +254,7 @@ int hexedit_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int hexedit_main(int argc UNUSED_PARAM, char **argv)
{
INIT_G();
INIT_PAGESIZE();
INIT_PAGESIZE(G.pagesize);
get_terminal_width_height(-1, NULL, &G.height);
if (1) {

7
miscutils/time.c
View File

@ -111,6 +111,10 @@ static void printargv(char *const *argv)
This is funky since the pagesize could be less than 1K.
Note: Some machines express getrusage statistics in terms of K,
others in terms of pages. */
#ifdef BB_ARCH_FIXED_PAGESIZE
# define pagesize BB_ARCH_FIXED_PAGESIZE
# define ptok(pagesize, pages) ptok(pages)
#endif
static unsigned long ptok(const unsigned pagesize, const unsigned long pages)
{
unsigned long tmp;
@ -124,6 +128,7 @@ static unsigned long ptok(const unsigned pagesize, const unsigned long pages)
tmp = pages * pagesize; /* Larger first, */
return tmp / 1024; /* then smaller. */
}
#undef pagesize
/* summarize: Report on the system use of a command.
@ -177,7 +182,7 @@ static void summarize(const char *fmt, char **command, resource_t *resp)
{
unsigned vv_ms; /* Elapsed virtual (CPU) milliseconds */
unsigned cpu_ticks; /* Same, in "CPU ticks" */
unsigned pagesize = getpagesize();
unsigned pagesize = bb_getpagesize();
/* Impossible: we do not use WUNTRACED flag in wait()...
if (WIFSTOPPED(resp->waitstatus))

2
util-linux/mkswap.c
View File

@ -128,7 +128,7 @@ int mkswap_main(int argc UNUSED_PARAM, char **argv)
/* Figure out how big the device is */
len = get_volume_size_in_bytes(fd, argv[1], 1024, /*extend:*/ 1);
pagesize = getpagesize();
pagesize = bb_getpagesize();
len -= pagesize;
/* Announce our intentions */