On 9/19/22 22:51, Liu Shixin wrote:
Patch f02c69680088 introduced register_hotmemory_notifier() to avoid a compile problem with gcc-4.4.4: When CONFIG_MEMORY_HOTPLUG=n, we don't want the memory-hotplug notifier handlers to be included in the .o files, for space reasons.The existing hotplug_memory_notifier() tries to handle this but testingwith gcc-4.4.4 shows that it doesn't work - the hotplug functions are still present in the .o files. Since patch 316346243be6 has already updated the minimum gcc version to 5.1. The previous problem mentioned in patch f02c69680088 is not existed. So we can now revert to use hotplug_memory_notifier() directly rather than register_hotmemory_notifier(). Patch [1-6] replace register_hotmemory_notifier() with hotplug_memory_notifier() for every caller. Patch [7] remove unused register_hotmemory_notifier(). Patch [8] replace IPC_CALLBACK_PRI with MM_BATCH_CALLBACK_PRI. Patch [9] collect all priority of hotplug memory callback into include/linux/memory.h for easy reading. v1->v2: fix compile error of patch [4,5].
I agreed with David's comments about patch 8 and 9. My understanding is that this patch series makes it easy to see all the priorities of the various memory hotplug notifier callbacks and hence their calling order. It is kind of being stated when mentioning about patch 9 above. However, it should be more prominently mentioned as the first thing that I look for is the benefit provided by this patch series.
Cheers, Longman
