This reverts commit e6e9d6e290028b0a6b83b563fad9fafa7f1d515e. It was a 4.19.31 backport of commit 6ea183d60c46 ("mm: handle lru_add_drain_all for UP properly"). In summary, what that did was to fix a possible harmless WARN_ON on non-SMP, introduced at commit 4d43d395fed1 ("workqueue: Try to catch flush_work() without INIT_WORK().") by adding non-SMP variants of lru functions.
The combination of that, with the -rt commit 473f14a9f234 ("mm: perform lru_add_drain_all() remotely") at the merge of the two results in the following build failure: mm/swap.c:736:2: error: #endif without #if since the -rt change wants RT specific lru and the stable backport wants non-SMP specific lru, and a chunk of the backport with an #ifdef CONFIG_SMP is missing. However, before we add a four way cluster of ifdeffery to handle all cases, we note 4d43d395fed1 was added to the v5.1 release, and it was not (currently) backported to any 4.19.x stable release - so it is unclear to me why this commit was ever backported to 4.19.31 at all. Further, we note this change was to mm/swap.c -- and by definition, any preempt-rt deployment that uses swap for anything other than a failure contingency mitigation is broken by design. Given all that, I decided that the best path forward was to revert the two of the three chunks of the backport that remain in the -rt branch, and return us to the pre-4.19.31 merge behaviour for -rt. Signed-off-by: Paul Gortmaker <paul.gortma...@windriver.com> diff --git a/mm/swap.c b/mm/swap.c index 7e0bcaf450a5..9217027671c8 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -325,6 +325,11 @@ static inline void activate_page_drain(int cpu) { } +static bool need_activate_page_drain(int cpu) +{ + return false; +} + void activate_page(struct page *page) { struct zone *zone = page_zone(page); @@ -728,12 +733,6 @@ void lru_add_drain_all(void) mutex_unlock(&lock); } -#else -void lru_add_drain_all(void) -{ - lru_add_drain(); -} -#endif /** * release_pages - batched put_page() -- 2.7.4 -- _______________________________________________ linux-yocto mailing list linux-yocto@yoctoproject.org https://lists.yoctoproject.org/listinfo/linux-yocto