On Mon, Dec 18, 2023 at 10:34:51AM -0800, Andrew Morton wrote: > On Sat, 16 Dec 2023 19:43:41 +0800 Kevin Hao <haokexin@xxxxxxxxx> wrote: > > > A freezable kernel thread can enter frozen state during freezing by > > either calling try_to_freeze() or using wait_event_freezable() and its > > variants. However, there is no need to use both methods simultaneously. > > The freezable wait variants have been used in khugepaged_wait_work() > > and khugepaged_alloc_sleep(), so remove this unnecessary > > try_to_freeze(). > > > > Looks OK to me, but this will increase freezing latencies. How > significant is this? I don't think this would cause observable freezing latencies, and most of time, we won't enter the freezing state, it is worthwhile to reduce the overhead of a function call. On my Intel Alder Lake board (24 CPUs, 32G memory) with transparent hugepage enabled. Before this patch: Freezing user space processes Freezing user space processes completed (elapsed 0.000 seconds) OOM killer disabled. Freezing remaining freezable tasks Freezing remaining freezable tasks completed (elapsed 0.001 seconds) After this patch: Freezing user space processes Freezing user space processes completed (elapsed 0.000 seconds) OOM killer disabled. Freezing remaining freezable tasks Freezing remaining freezable tasks completed (elapsed 0.001 seconds) > > Also, we already have a patch from you with this same title. Please > try to use different titles for different patches. Sure, I will tweak it in v2. Thanks, Kevin
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