Hi Kent,
On Fri, 22 Apr 2022 at 07:56, Kent Overstreet <kent.overstreet@xxxxxxxxx> wrote:
>
> Debugging OOMs has been one of my sources of frustration, so this patch series
> is an attempt to do something about it.
>
> The first patch in the series is something I've been slowly evolving in bcachefs
> for years: simple heap allocated strings meant for appending to and building up
> structured log/error messages. They make it easy and straightforward to write
> pretty-printers for everything, which in turn makes good logging and error
> messages something that just happens naturally.
>
> We want it here because that means the reporting I'm adding to shrinkers can be
> used by both OOM reporting, and for the sysfs (or is it debugfs now) interface
> that Roman is adding.
>
I added the kexec list in cc. It seems like a nice enhancement to oom
reporting.
I suspect kdump tooling need changes to retrieve the kmsg log from
vmcore, could you confirm it? For example makedumpfile, crash, and
kexec-tools (its vmcore-dmesg tool).
> This patch series also:
> - adds OOM reporting on shrinkers, reporting on top 10 shrinkers (in sorted
> order!)
> - changes slab reporting to be always-on, also reporting top 10 slabs in sorted
> order
> - starts centralizing OOM reporting in mm/show_mem.c
>
> The last patch in the series is only a demonstration of how to implement the
> shrinker .to_text() method, since bcachefs isn't upstream yet.
>
> Kent Overstreet (4):
> lib/printbuf: New data structure for heap-allocated strings
> mm: Add a .to_text() method for shrinkers
> mm: Centralize & improve oom reporting in show_mem.c
> bcachefs: shrinker.to_text() methods
>
> fs/bcachefs/btree_cache.c | 18 ++-
> fs/bcachefs/btree_key_cache.c | 18 ++-
> include/linux/printbuf.h | 140 ++++++++++++++++++
> include/linux/shrinker.h | 5 +
> lib/Makefile | 4 +-
> lib/printbuf.c | 271 ++++++++++++++++++++++++++++++++++
> mm/Makefile | 2 +-
> mm/oom_kill.c | 23 ---
> {lib => mm}/show_mem.c | 14 ++
> mm/slab.h | 6 +-
> mm/slab_common.c | 53 ++++++-
> mm/vmscan.c | 75 ++++++++++
> 12 files changed, 587 insertions(+), 42 deletions(-)
> create mode 100644 include/linux/printbuf.h
> create mode 100644 lib/printbuf.c
> rename {lib => mm}/show_mem.c (78%)
>
> --
> 2.35.2
>
Thanks
Dave
