libbb: add and use infrastructure for fixed page size optimization

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

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.