[RFC PATCH 0/5] replace runtime slub_debug toggling with more capable boot parameter

From: Vlastimil Babka
Date: Tue Jun 02 2020 - 10:16:13 EST


we had recently reports [1,2] of troubles with runtime writes to various SLUB
per-cache sysfs files related to slub_debug or tuning leading to crashes. I have
inspected all those writable files and the rather unfortunate result is that
most of them are made read-only by this patchset, as fixing the issues doesn't
seem viable. Details for each are given in each patch. I expect some
resistance, hence the RFC.

The runtime toggles were however necessary for the use case described in [3],
so the first patch extends the slub_debug boot parameter syntax to achieve the
same configuration without runtime toggles. That should hopefully make the
changes more feasible.

[1] https://lkml.kernel.org/r/1580379523-32272-1-git-send-email-vjitta@xxxxxxxxxxxxxx
[2] https://lore.kernel.org/r/CAG48ez31PP--h6_FzVyfJ4H86QYczAFPdxtJHUEEan+7VJETAQ@xxxxxxxxxxxxxx
[3] https://lore.kernel.org/r/1383cd32-1ddc-4dac-b5f8-9c42282fa81c@xxxxxxxxxxxxxx

Vlastimil Babka (5):
mm, slub: extend slub_debug syntax for multiple blocks
mm, slub: make some slub_debug related attributes read-only
mm, slub: remove runtime allocation order changes
mm, slub: make remaining slub_debug related attributes read-only
mm, slub: make reclaim_account attribute read-only

.../admin-guide/kernel-parameters.txt | 2 +-
Documentation/vm/slub.rst | 36 +-
mm/slub.c | 315 ++++++++----------
3 files changed, 163 insertions(+), 190 deletions(-)