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| author | William Cohen <wcohen@redhat.com> | 2007-05-08 00:23:41 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-08 11:14:58 -0700 |
| commit | 97dc32cdb1b53832801159d5f634b41aad9d0a23 (patch) | |
| tree | 438f59c84d3528de5f68583d312beceb1aa32659 /fs | |
| parent | 4d7bf11d649c72621ca31b8ea12b9c94af380e63 (diff) | |
| download | op-kernel-dev-97dc32cdb1b53832801159d5f634b41aad9d0a23.zip op-kernel-dev-97dc32cdb1b53832801159d5f634b41aad9d0a23.tar.gz | |
reduce size of task_struct on 64-bit machines
This past week I was playing around with that pahole tool
(http://oops.ghostprotocols.net:81/acme/dwarves/) and looking at the size
of various struct in the kernel. I was surprised by the size of the
task_struct on x86_64, approaching 4K. I looked through the fields in
task_struct and found that a number of them were declared as "unsigned
long" rather than "unsigned int" despite them appearing okay as 32-bit
sized fields. On x86_64 "unsigned long" ends up being 8 bytes in size and
forces 8 byte alignment. Is there a reason there a reason they are
"unsigned long"?
The patch below drops the size of the struct from 3808 bytes (60 64-byte
cachelines) to 3760 bytes (59 64-byte cachelines). A couple other fields
in the task struct take a signficant amount of space:
struct thread_struct thread; 688
struct held_lock held_locks[30]; 1680
CONFIG_LOCKDEP is turned on in the .config
[akpm@linux-foundation.org: fix printk warnings]
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/proc/array.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/proc/array.c b/fs/proc/array.c index 07c9cdb..74f30e0 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -410,9 +410,9 @@ static int do_task_stat(struct task_struct *task, char * buffer, int whole) /* convert nsec -> ticks */ start_time = nsec_to_clock_t(start_time); - res = sprintf(buffer,"%d (%s) %c %d %d %d %d %d %lu %lu \ + res = sprintf(buffer,"%d (%s) %c %d %d %d %d %d %u %lu \ %lu %lu %lu %lu %lu %ld %ld %ld %ld %d 0 %llu %lu %ld %lu %lu %lu %lu %lu \ -%lu %lu %lu %lu %lu %lu %lu %lu %d %d %lu %lu %llu\n", +%lu %lu %lu %lu %lu %lu %lu %lu %d %d %u %u %llu\n", task->pid, tcomm, state, |
