mm/migrate: do not call prep_transhuge_page if !thp_migration_supported
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| # | Subject and files | Size | Replies | Applied |
|---|---|---|---|---|
| 1/1 | mm/migrate: do not call prep_transhuge_page if !thp_migration_supportedinclude/ | +1 | 2 replies |
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Cover letter [PATCH 0/1] mm/migrate: do not call prep_transhuge_page if !thp_migration_supported
Hi all,
While working on a second round of patches to introduce memory hotplug / hot remove to arm64 (original attempt at [1]), and trying to rebase them on 4.14, I stumbled in some problematic behaviour during page migration when offlining for hot remove, whereas target pages for migration where found in a bad state.
I believe that this behaviour may be originating from commit 8135d8926c08 ("mm: memory_hotplug: memory hotremove supports thp migration") and it is triggered when migrating pages for builds that have no ARCH_ENABLE_THP_MIGRATION but have thp support on (arm64, in my case). Specifically, my understanding is that prep_transhuge_page should not be called in linux/migrate.h:new_page_nodemask if !thp_migration_supported because, in that case, new_page would not be a thp.
A tiny patch follows, showing what I mean. Please, let me know if my understanding is bogus.
Best regards,
Andrea
[1] https://lkml.org/lkml/2017/4/11/536
Andrea Reale (1):
mm/migrate: do not call prep_transhuge_page if
!thp_migration_supported
include/linux/migrate.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
Signature · 1 line
2.7.4