On 5/20/21 6:34 AM, Andrew Morton wrote: > On Wed, 19 May 2021 21:17:43 +0100 Aaron Tomlin <atomlin@xxxxxxxxxx> wrote: > >> It does not make sense to retry compaction when a fatal signal is >> pending. > > Well, it might make sense. Presumably it is beneficial to other tasks. Yeah but the compaction won't happen. compact_zone() will immediately detect it via __compact_finished() and bail out. So in that sense it does not make sense to retry :) >> In the context of try_to_compact_pages(), indeed COMPACT_SKIPPED can be >> returned; albeit, not every zone, on the zone list, would be considered >> in the case a fatal signal is found to be pending. >> Yet, in should_compact_retry(), given the last known compaction result, >> each zone, on the zone list, can be considered/or checked >> (see compaction_zonelist_suitable()). For example, if a zone was found >> to succeed, then reclaim/compaction would be tried again >> (notwithstanding the above). >> >> This patch ensures that compaction is not needlessly retried >> irrespective of the last known compaction result e.g. if it was skipped, >> in the unlikely case a fatal signal is found pending. >> So, OOM is at least attempted. > > What observed problems motivated this change? > > What were the observed runtime effects of this change? Yep those details from the previous thread should be included here.
