I'm worried about what will happen with things like
KERNELS=="*" # pointless rule
KERNELS=="doesnt-match" # another pointless rule
Since TK_RULE < TK_M_PARENTS_MAX, we will try to match all three tokens
against parents of the current device. I can't think of a bad case,
but it's not exactly good either.
Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
LAST_RULE was broken, and I broke TK_END by making it do the same.
It used a "break" which exited the switch statement, but not the loop!
==2953== Invalid read of size 4
==2953== at 0x4081EE: dump_token (udev-rules.c:859)
==2953== by 0x40BADB: udev_rules_apply_to_event (udev-rules.c:1849)
==2953== by 0x403F17: udev_event_execute_rules (udev-event.c:554)
==2953== by 0x418626: main (test-udev.c:100)
==2953== Address 0x55ab1f8 is 0 bytes after a block of size 80 alloc'd
==2953== at 0x4C23082: realloc (vg_replace_malloc.c:429)
==2953== by 0x40B13B: udev_rules_new (udev-rules.c:1670)
==2953== by 0x418536: main (test-udev.c:84)
...
Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
On Thu, Oct 30, 2008 at 03:55, Tejun Heo <tj@kernel.org> wrote:
The appropriate default timeout differs depending on the transport and
the type of the attached device, so the above two rules harm more than
help. The affect of the above two rules weren't visible for some
reason but with recent block layer timeout update, they actually work
and cause problems.
Initializing a char array to "" is equivalent to a memset()
call - which is exactly what it gets compiled to.
Fixing this one callsite reduced memset() _user_ cpu cycles
from 2-4% to 0.05% on the EeePC.
Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
This crops up in my threaded udevd profiles from time to time.
It's not consistent - probably due to variations in the number
of concurrent events - but it can hit 4% user time and higher.
The change halves the user time spent in compare_devpath().
Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
The wait should be ordered after matching KERNEL, ENV, etc.
but before ATTR.
Without this, WAIT_FOR_SYSFS rules will be applied unconditionally
to all events.
Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Re: b99028c963 shrink struct udev_event
TEST 136: test multi matches 2
device '/devices/pci0000:00/0000:00:1d.7/usb5/5-2/5-2:1.0/tty/ttyACM0' expecting node 'right'
==15011==
==15011== 7 bytes in 1 blocks are definitely lost in loss record 1 of 1
==15011== at 0x47F9AB8: malloc (vg_replace_malloc.c:207)
==15011== by 0x489CB5F: strdup (in /lib32/libc-2.7.so)
==15011== by 0x8050F40: udev_rules_apply_to_event (udev-rules.c:1973)
==15011== by 0x804A658: udev_event_execute_rules (udev-event.c:549)
==15011== by 0x805A636: main (test-udev.c:100)
add: ok
==15012==
==15012== 7 bytes in 1 blocks are definitely lost in loss record 1 of 1
==15012== at 0x47F1AB8: malloc (vg_replace_malloc.c:207)
==15012== by 0x4898B5F: strdup (in /lib32/libc-2.7.so)
==15012== by 0x8050F40: udev_rules_apply_to_event (udev-rules.c:1973)
==15012== by 0x804A9DF: udev_event_execute_rules (udev-event.c:658)
==15012== by 0x805A636: main (test-udev.c:100)
remove: ok
Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
The in-memory rule array of a common desktop distro install took:
1151088 bytes
with the token list:
109232 bytes tokens (6827 * 16 bytes), 71302 bytes buffer
The problem was strncpy() doesn't stop after writing the terminating
NUL; by definition it goes on to zero the entire buffer.
I spy another use of strncpy in udev_device_add_property_from_string(),
which is responsible for another ~1% user cpu time...
Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Since we already know the length, use memcpy() instead.
Measured 2% _user_ cpu time reduction on EeePC coldplug.
Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Use calloc to request cleared memory instead.
Kernel and libc conspire to make this more efficient.
Also, replace one malloc() + strcpy() with strdup().
Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
