mm, page_owner: skip unnecessary stack_trace entries

The page_owner stacktrace always begin as follows:

[<ffffff987bfd48f4>] save_stack+0x40/0xc8
[<ffffff987bfd4da8>] __set_page_owner+0x3c/0x6c

These two entries do not provide any useful information and limits the
available stacktrace depth.  The page_owner stacktrace was skipping caller
function from stack entries but this was missed with commit f2ca0b55
("mm/page_owner: use stackdepot to store stacktrace")

Example page_owner entry after the patch:

Page allocated via order 0, mask 0x8(ffffff80085fb714)
PFN 654411 type Movable Block 639 type CMA Flags 0x0(ffffffbe5c7f12c0)
[<ffffff9b64989c14>] post_alloc_hook+0x70/0x80
...
[<ffffff9b651216e8>] msm_comm_try_state+0x5f8/0x14f4
[<ffffff9b6512486c>] msm_vidc_open+0x5e4/0x7d0
[<ffffff9b65113674>] msm_v4l2_open+0xa8/0x224

Change-Id: Ia34fc127d691c2858d991bb631aad9ebc703bcee
Link: http://lkml.kernel.org/r/1504078343-28754-2-git-send-email-guptap@codeaurora.org


Fixes: f2ca0b55 ("mm/page_owner: use stackdepot to store stacktrace")
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Git-commit: 665bb76dd71bc061c5f730226dc1881d151983c8
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git


Signed-off-by: Prakash Gupta <guptap@codeaurora.org>