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authorBalbir Singh <balbir@in.ibm.com>2007-04-23 14:41:05 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2007-05-01 17:06:02 -0700
commit2b2c594d5faa4c85db286ed015df78ee02138eec (patch)
tree6e20557dbd250ec149eaf944095d393cf0f7a1c8
parent637fc7e479a60ae55357c0e3ffeca5a475ef5733 (diff)
downloadlinux-linaro-stable-2b2c594d5faa4c85db286ed015df78ee02138eec.tar.gz
Taskstats fix the structure members alignment issue
We broke the the alignment of members of taskstats to the 8 byte boundary with the CSA patches. In the current kernel, the taskstats structure is not suitable for use by 32 bit applications in a 64 bit kernel. On x86_64 Offsets of taskstats' members (64 bit kernel, 64 bit application) @taskstats'offsetof[@taskstats'indices] = ( 0, # version 4, # ac_exitcode 8, # ac_flag 9, # ac_nice 16, # cpu_count 24, # cpu_delay_total 32, # blkio_count 40, # blkio_delay_total 48, # swapin_count 56, # swapin_delay_total 64, # cpu_run_real_total 72, # cpu_run_virtual_total 80, # ac_comm 112, # ac_sched 113, # ac_pad 116, # ac_uid 120, # ac_gid 124, # ac_pid 128, # ac_ppid 132, # ac_btime 136, # ac_etime 144, # ac_utime 152, # ac_stime 160, # ac_minflt 168, # ac_majflt 176, # coremem 184, # virtmem 192, # hiwater_rss 200, # hiwater_vm 208, # read_char 216, # write_char 224, # read_syscalls 232, # write_syscalls 240, # read_bytes 248, # write_bytes 256, # cancelled_write_bytes ); Offsets of taskstats' members (64 bit kernel, 32 bit application) @taskstats'offsetof[@taskstats'indices] = ( 0, # version 4, # ac_exitcode 8, # ac_flag 9, # ac_nice 12, # cpu_count 20, # cpu_delay_total 28, # blkio_count 36, # blkio_delay_total 44, # swapin_count 52, # swapin_delay_total 60, # cpu_run_real_total 68, # cpu_run_virtual_total 76, # ac_comm 108, # ac_sched 109, # ac_pad 112, # ac_uid 116, # ac_gid 120, # ac_pid 124, # ac_ppid 128, # ac_btime 132, # ac_etime 140, # ac_utime 148, # ac_stime 156, # ac_minflt 164, # ac_majflt 172, # coremem 180, # virtmem 188, # hiwater_rss 196, # hiwater_vm 204, # read_char 212, # write_char 220, # read_syscalls 228, # write_syscalls 236, # read_bytes 244, # write_bytes 252, # cancelled_write_bytes ); This is one way to solve the problem without re-arranging structure members is to pack the structure. The patch adds an __attribute__((aligned(8))) to the taskstats structure members so that 32 bit applications using taskstats can work with a 64 bit kernel. Using __attribute__((packed)) would break the 64 bit alignment of members. The fix was tested on x86_64. After the fix, we got Offsets of taskstats' members (64 bit kernel, 64 bit application) @taskstats'offsetof[@taskstats'indices] = ( 0, # version 4, # ac_exitcode 8, # ac_flag 9, # ac_nice 16, # cpu_count 24, # cpu_delay_total 32, # blkio_count 40, # blkio_delay_total 48, # swapin_count 56, # swapin_delay_total 64, # cpu_run_real_total 72, # cpu_run_virtual_total 80, # ac_comm 112, # ac_sched 113, # ac_pad 120, # ac_uid 124, # ac_gid 128, # ac_pid 132, # ac_ppid 136, # ac_btime 144, # ac_etime 152, # ac_utime 160, # ac_stime 168, # ac_minflt 176, # ac_majflt 184, # coremem 192, # virtmem 200, # hiwater_rss 208, # hiwater_vm 216, # read_char 224, # write_char 232, # read_syscalls 240, # write_syscalls 248, # read_bytes 256, # write_bytes 264, # cancelled_write_bytes ); Offsets of taskstats' members (64 bit kernel, 32 bit application) @taskstats'offsetof[@taskstats'indices] = ( 0, # version 4, # ac_exitcode 8, # ac_flag 9, # ac_nice 16, # cpu_count 24, # cpu_delay_total 32, # blkio_count 40, # blkio_delay_total 48, # swapin_count 56, # swapin_delay_total 64, # cpu_run_real_total 72, # cpu_run_virtual_total 80, # ac_comm 112, # ac_sched 113, # ac_pad 120, # ac_uid 124, # ac_gid 128, # ac_pid 132, # ac_ppid 136, # ac_btime 144, # ac_etime 152, # ac_utime 160, # ac_stime 168, # ac_minflt 176, # ac_majflt 184, # coremem 192, # virtmem 200, # hiwater_rss 208, # hiwater_vm 216, # read_char 224, # write_char 232, # read_syscalls 240, # write_syscalls 248, # read_bytes 256, # write_bytes 264, # cancelled_write_bytes ); Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Jay Lan <jlan@engr.sgi.com> Cc: Shailabh Nagar <nagar@watson.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--include/linux/taskstats.h13
1 files changed, 8 insertions, 5 deletions
diff --git a/include/linux/taskstats.h b/include/linux/taskstats.h
index 3fced4798255..a46104a28f66 100644
--- a/include/linux/taskstats.h
+++ b/include/linux/taskstats.h
@@ -31,7 +31,7 @@
*/
-#define TASKSTATS_VERSION 3
+#define TASKSTATS_VERSION 4
#define TS_COMM_LEN 32 /* should be >= TASK_COMM_LEN
* in linux/sched.h */
@@ -66,7 +66,7 @@ struct taskstats {
/* Delay waiting for cpu, while runnable
* count, delay_total NOT updated atomically
*/
- __u64 cpu_count;
+ __u64 cpu_count __attribute__((aligned(8)));
__u64 cpu_delay_total;
/* Following four fields atomically updated using task->delays->lock */
@@ -101,14 +101,17 @@ struct taskstats {
/* Basic Accounting Fields start */
char ac_comm[TS_COMM_LEN]; /* Command name */
- __u8 ac_sched; /* Scheduling discipline */
+ __u8 ac_sched __attribute__((aligned(8)));
+ /* Scheduling discipline */
__u8 ac_pad[3];
- __u32 ac_uid; /* User ID */
+ __u32 ac_uid __attribute__((aligned(8)));
+ /* User ID */
__u32 ac_gid; /* Group ID */
__u32 ac_pid; /* Process ID */
__u32 ac_ppid; /* Parent process ID */
__u32 ac_btime; /* Begin time [sec since 1970] */
- __u64 ac_etime; /* Elapsed time [usec] */
+ __u64 ac_etime __attribute__((aligned(8)));
+ /* Elapsed time [usec] */
__u64 ac_utime; /* User CPU time [usec] */
__u64 ac_stime; /* SYstem CPU time [usec] */
__u64 ac_minflt; /* Minor Page Fault Count */