Some background about why I think this might be useful.
When I was profiling some hugetlb related program, I got page-faults event doubled when hugetlb is enabled. When I looked into the code, I found page-faults come from two places, do_page_fault and gup. So, I tried to figure out which play a role (or both) in my use case. But I can't find existing finer tracing event for sub page-faults in current mainline kernel.
So, I added the gup trace points support to have finer tracing events for page-faults. The below events are added:
__get_user_pages __get_user_pages_fast fixup_user_fault
Both __get_user_pages and fixup_user_fault call handle_mm_fault.
Just added trace points to raw version __get_user_pages since all variants will call it finally to do real work.
Although __get_user_pages_fast doesn't call handle_mm_fault, it might be useful to have it to distinguish between slow and fast version.
Yang Shi (7): trace/events: Add gup trace events mm/gup: add gup trace points x86: mm/gup: add gup trace points mips: mm/gup: add gup trace points s390: mm/gup: add gup trace points sh: mm/gup: add gup trace points sparc64: mm/gup: add gup trace points
arch/mips/mm/gup.c | 7 +++++++ arch/s390/mm/gup.c | 7 +++++++ arch/sh/mm/gup.c | 8 ++++++++ arch/sparc/mm/gup.c | 8 ++++++++ arch/x86/mm/gup.c | 7 +++++++ include/trace/events/gup.h | 77 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ mm/gup.c | 8 ++++++++ 7 files changed, 122 insertions(+)