On 11/12/25 10:50, Andrew Morton wrote: > On Mon, 10 Nov 2025 16:19:54 -0500 Steven Rostedt <[email protected]> wrote: > >> On Thu, 16 Oct 2025 16:46:19 +1100 >> Balbir Singh <[email protected]> wrote: >> >>> Add tracepoints for debugging device migration flow in migrate_device.c. >>> This is helpful in debugging how long migration took (time can be >>> tracked backwards from migrate_device_finalize to migrate_vma_setup). >>> >>> A combination of these events along with existing thp:*, exceptions:* >>> and migrate:* is very useful for debugging issues related to >>> migration. >>> >> >> ... >> >>> hmm-tests-855 [002] 50.042800: set_migration_pmd: >>> addr=7f2908a00000, pmd=dfffffffd39ffe00 >>> hmm-tests-855 [002] 50.062345: remove_migration_pmd: >>> addr=7f2908a00000, pmd=efffffe00403fe00 >> >> Each TRACE_EVENT() is equivalent to: >> >> DECLARE_EVENT_CLASS(event, ...) >> DEFINE_EVENT(event, event, ...) >> >> Where a class is around 4-5K in size, and the DEFINE_EVENT is between >> 500 and 1k in size. >> >> By using a single DECLARE_EVENT_CLASS() for multiple events, you can save >> several thousands of bytes of memory. > > Thanks for the detailed review. I'll drop this version of the patch.
Thanks Steve and Andrew! I've been looking at EVENT_CLASSES and looking for the savings you mentioned. I've not yet finished my patch, I will resend it as soon as I have a new version Balbir
