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mdev: improve $SEQ handling; improve debug logging

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Sequential run of concurrent mdev's was too simplistic:
they waited for /dev/mdev.seq to match. This could sometimes
cause cumulative loss of time on the order of a second.

Added SIGCHLD signaling from exiting mdev to all other mdev's.
Added debugging required to see that code actually works as intended.

Example of /dev/mdev.log (with "woken up" elevated from dbg lvl 3 to 2):

mdev[1023]: first seq written
     ^^^^ seq, not pid
mdev[1023]: 35.022395 ACTION:add SUBSYSTEM:module DEVNAME:(null) DEVPATH:/module/lib80211
mdev[1023]: rule matched, line -1
                          ^^^^^^^ means "default rule"
mdev[1023]: 35.022676 exiting
            ^^^^^^^^^ second,usec timestamp
mdev[1024]: 35.069691 ACTION:add SUBSYSTEM:vc DEVNAME:vcs9 DEVPATH:/devices/virtual/vc/vcs9
mdev[1024]: dev 7,9
mdev[1025]: 35.069889 waiting for '1024'
mdev[1026]: 35.069946 waiting for '1024'
mdev[1027]: 35.070151 waiting for '1024'
mdev[1024]: rule matched, line -1
mdev[1024]: mknod vcs9 (7,9) 20660 0:0
mdev[1024]: 35.070346 exiting
mdev[1025]: woken up
mdev[1026]: woken up
mdev[1025]: 35.071213 ACTION:add SUBSYSTEM:vc DEVNAME:vcsa9 DEVPATH:/devices/virtual/vc/vcsa9
            ^^^^^^^^^ took only a millisecond to start running after prev mdev exited
mdev[1025]: dev 7,137
mdev[1027]: woken up
mdev[1025]: rule matched, line -1
mdev[1025]: mknod vcsa9 (7,137) 20660 0:0
mdev[1025]: 35.072109 exiting

function                                             old     new   delta
mdev_main                                            849    1372    +523
curtime                                                -      59     +59
dirAction                                             87     134     +47
static.ts                                              -       8      +8
keywords                                              19      12      -7
make_device                                         2189    2119     -70

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2013-02-27 10:51:41 +01:00
parent 9fed24c031
commit 5bce135e36
2 changed files with 180 additions and 90 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
examples/mdev_fat.conf
View File

@@ -7,9 +7,9 @@
# instead of the default 0:0 660.
#
# Syntax:
# [-]devicename_regex user:group mode [=path]|[>path]|[!] [@|$|*cmd args...]
# [-]$ENVVAR=regex user:group mode [=path]|[>path]|[!] [@|$|*cmd args...]
# [-]@maj,min[-min2] user:group mode [=path]|[>path]|[!] [@|$|*cmd args...]
# [-][ENVVAR=regex;]...devicename_regex user:group mode [=path]|[>path]|[!] [@|$|*cmd args...]
# [-][ENVVAR=regex;]...@maj,min[-min2] user:group mode [=path]|[>path]|[!] [@|$|*cmd args...]
# [-]$ENVVAR=regex user:group mode [=path]|[>path]|[!] [@|$|*cmd args...]
#
# [-]: do not stop on this match, continue reading mdev.conf
# =: move, >: move and create a symlink
@@ -53,6 +53,7 @@ sr[0-9]* root:cdrom 660 @ln -sf $MDEV cdrom
fd[0-9]* root:floppy 660
# net devices
SUBSYSTEM=net;.* root:root 600 @nameif
tun[0-9]* root:root 600 =net/
tap[0-9]* root:root 600 =net/