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Cache the result of getpagesize() so we only make one syscall.

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Use getpagesize instead of CLBYTES.
This commit is contained in:
Poul-Henning Kamp 1996-05-02 08:43:05 +00:00
parent 3a91de068c
commit d71458ee72
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=15528
2 changed files with 19 additions and 16 deletions
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20
lib/libc/gen/getpagesize.c
View File

@ -38,16 +38,24 @@ static char sccsid[] = "@(#)getpagesize.c 8.1 (Berkeley) 6/4/93";
#include <sys/param.h>
#include <sys/sysctl.h>
/*
* This is unlikely to change over the running time of any
* program, so we cache the result to save some syscalls.
*/
int
getpagesize()
{
int mib[2], value;
int mib[2];
static int value;
size_t size;
mib[0] = CTL_HW;
mib[1] = HW_PAGESIZE;
size = sizeof value;
if (sysctl(mib, 2, &value, &size, NULL, 0) == -1)
return (-1);
if (!value) {
mib[0] = CTL_HW;
mib[1] = HW_PAGESIZE;
size = sizeof value;
if (sysctl(mib, 2, &value, &size, NULL, 0) == -1)
return (-1);
}
return (value);
}

15
lib/libc/gen/opendir.c
View File

@ -79,18 +79,13 @@ opendir(name)
(dirp = malloc(sizeof(DIR))) == NULL)
goto fail;
/*
* If CLBYTES is an exact multiple of DIRBLKSIZ, use a CLBYTES
* buffer that it cluster boundary aligned.
* Hopefully this can be a big win someday by allowing page trades
* to user space to be done by getdirentries()
* Use the system page size if that is a multiple of DIRBLKSIZ
* this could speed things up in some cases we hope
*/
if ((CLBYTES % DIRBLKSIZ) == 0) {
dirp->dd_buf = malloc(CLBYTES);
dirp->dd_len = CLBYTES;
} else {
dirp->dd_buf = malloc(DIRBLKSIZ);
dirp->dd_len = getpagesize();
if ((dirp->dd_len % DIRBLKSIZ) != 0)
dirp->dd_len = DIRBLKSIZ;
}
dirp->dd_buf = malloc(dirp->dd_len);
if (dirp->dd_buf == NULL)
goto fail;
dirp->dd_fd = fd;