linux/fs/pstore
Joel Fernandes fbccdeb8d7 pstore: Add ftrace timestamp counter
In preparation for merging the per CPU buffers into one buffer when
we retrieve the pstore ftrace data, we store the timestamp as a
counter in the ftrace pstore record.  We store the CPU number as well
if !PSTORE_CPU_IN_IP, in this case we shift the counter and may lose
ordering there but we preserve the same record size. The timestamp counter
is also racy, and not doing any locking or synchronization here results
in the benefit of lower overhead. Since we don't care much here for exact
ordering of function traces across CPUs, we don't synchronize and may lose
some counter updates but I'm ok with that.

Using trace_clock() results in much lower performance so avoid using it
since we don't want accuracy in timestamp and need a rough ordering to
perform merge.

Signed-off-by: Joel Fernandes <joelaf@google.com>
[kees: updated commit message, added comments]
Signed-off-by: Kees Cook <keescook@chromium.org>
2016-11-15 16:34:27 -08:00
..
ftrace.c pstore: Add ftrace timestamp counter 2016-11-15 16:34:27 -08:00
inode.c pstore: Add ftrace timestamp counter 2016-11-15 16:34:27 -08:00
internal.h pstore: Add ftrace timestamp counter 2016-11-15 16:34:27 -08:00
Kconfig pstore: add lzo/lz4 compression support 2016-06-02 10:59:31 -07:00
Makefile pstore: add pstore unregister 2015-10-22 08:59:18 -07:00
platform.c pstore: Actually give up during locking failure 2016-11-08 16:44:33 -08:00
pmsg.c pstore/pmsg: drop bounce buffer 2016-09-08 15:01:10 -07:00
ram_core.c pstore: Allow prz to control need for locking 2016-11-15 16:34:25 -08:00
ram.c ramoops: Split ftrace buffer space into per-CPU zones 2016-11-15 16:34:26 -08:00