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| author |   Joel Fernandes <joelaf@google.com> | 2016-10-20 00:34:05 -0700 |
|---|---|---|
| committer |   Kees Cook <keescook@chromium.org> | 2016-11-15 16:34:27 -0800 |
| commit | fbccdeb8d77d6830556bc4079eeed80298cc97dc (patch) | |
| tree | c423e1973a8107db2ee1f6dd8ac70539fdee3fef /fs/pstore/inode.c | |
| parent | ramoops: Split ftrace buffer space into per-CPU zones (diff) | |
| download | linux-dev-fbccdeb8d77d6830556bc4079eeed80298cc97dc.tar.xz linux-dev-fbccdeb8d77d6830556bc4079eeed80298cc97dc.zip | |
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>
Diffstat (limited to 'fs/pstore/inode.c')
| -rw-r--r-- | fs/pstore/inode.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c index 1781dc50762e..0d6bbcf47d52 100644 --- a/fs/pstore/inode.c +++ b/fs/pstore/inode.c @@ -107,9 +107,11 @@ static int pstore_ftrace_seq_show(struct seq_file *s, void *v) struct pstore_ftrace_seq_data *data = v; struct pstore_ftrace_record *rec = (void *)(ps->data + data->off); - seq_printf(s, "%d %08lx %08lx %pf <- %pF\n", - pstore_ftrace_decode_cpu(rec), rec->ip, rec->parent_ip, - (void *)rec->ip, (void *)rec->parent_ip); + seq_printf(s, "CPU:%d ts:%llu %08lx %08lx %pf <- %pF\n", + pstore_ftrace_decode_cpu(rec), + pstore_ftrace_read_timestamp(rec), + rec->ip, rec->parent_ip, (void *)rec->ip, + (void *)rec->parent_ip); return 0; } |