tools/vm/page_owner_sort.c: sort by stacktrace before culling

The contents of page_owner have changed to include more information than
the stack trace.  On a modern kernel, the blocks look like

  Page allocated via order 0, mask 0x0(), pid 1, ts 165564237 ns, free_ts 0 ns
    register_early_stack+0x4b/0x90
    init_page_owner+0x39/0x250
    kernel_init_freeable+0x11e/0x242
    kernel_init+0x16/0x130

Sorting by the contents of .txt will result in almost no repeated pages,
as the pid, ts, and free_ts will almost never be the same.  Instead,
sort by the contents of the stack trace, which we assume to be whatever
is after the first line.

[[email protected]: fix NULL-pointer dereference when comparing stack traces]
  Link: https://lkml.kernel.org/r/[email protected]

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Sean Anderson <[email protected]>
Cc: Changhee Han <[email protected]>
Cc: Tang Bin <[email protected]>
Cc: Zhang Shengju <[email protected]>
Cc: Zhenliang Wei <[email protected]>
Cc: Stephen Rothwell <[email protected]>
Cc: Yinan Zhang <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions