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(+)
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