diff options
Diffstat (limited to 'sbin/fsck_ffs/fsutil.c')
| -rw-r--r-- | sbin/fsck_ffs/fsutil.c | 47 |
1 files changed, 46 insertions, 1 deletions
diff --git a/sbin/fsck_ffs/fsutil.c b/sbin/fsck_ffs/fsutil.c index 0ce8663..c684b94 100644 --- a/sbin/fsck_ffs/fsutil.c +++ b/sbin/fsck_ffs/fsutil.c @@ -40,6 +40,7 @@ static const char rcsid[] = #endif /* not lint */ #include <sys/param.h> +#include <sys/time.h> #include <sys/types.h> #include <sys/sysctl.h> #include <sys/disklabel.h> @@ -62,7 +63,13 @@ static const char rcsid[] = #include "fsck.h" +static void slowio_start(void); +static void slowio_end(void); + long diskreads, totalreads; /* Disk cache statistics */ +struct timeval slowio_starttime; +int slowio_delay_usec = 10000; /* Initial IO delay for background fsck */ +int slowio_pollcnt; int ftypeok(union dinode *dp) @@ -350,10 +357,15 @@ bread(int fd, char *buf, ufs2_daddr_t blk, long size) offset = blk; offset *= dev_bsize; + if (bkgrdflag) + slowio_start(); if (lseek(fd, offset, 0) < 0) rwerror("SEEK BLK", blk); - else if (read(fd, buf, (int)size) == size) + else if (read(fd, buf, (int)size) == size) { + if (bkgrdflag) + slowio_end(); return (0); + } rwerror("READ BLK", blk); if (lseek(fd, offset, 0) < 0) rwerror("SEEK BLK", blk); @@ -465,6 +477,39 @@ freeblk(ufs2_daddr_t blkno, long frags) (void)pass4check(&idesc); } +/* Slow down IO so as to leave some disk bandwidth for other processes */ +void +slowio_start() +{ + + /* Delay one in every 8 operations by 16 times the average IO delay */ + slowio_pollcnt = (slowio_pollcnt + 1) & 7; + if (slowio_pollcnt == 0) { + usleep(slowio_delay_usec * 16); + gettimeofday(&slowio_starttime, NULL); + } +} + +void +slowio_end() +{ + struct timeval tv; + int delay_usec; + + if (slowio_pollcnt != 0) + return; + + /* Update the slowdown interval. */ + gettimeofday(&tv, NULL); + delay_usec = (tv.tv_sec - slowio_starttime.tv_sec) * 1000000 + + (tv.tv_usec - slowio_starttime.tv_usec); + if (delay_usec < 64) + delay_usec = 64; + if (delay_usec > 1000000) + delay_usec = 1000000; + slowio_delay_usec = (slowio_delay_usec * 63 + delay_usec) >> 6; +} + /* * Find a pathname */ |
