On 6/22/23 11:53 AM, Anton Protopopov wrote:
Add a generic percpu stats for bpf_map elements insertions/deletions in order
to keep track of both, the current (approximate) number of elements in a map
and per-cpu statistics on update/delete operations.
To expose these stats a particular map implementation should initialize the
counter and adjust it as needed using the 'bpf_map_*_elements_counter' helpers
provided by this commit. The counter can be read by an iterator program.
A bpf_map_sum_elements_counter kfunc was added to simplify getting the sum of
the per-cpu values. If a map doesn't implement the counter, then it will always
return 0.
Signed-off-by: Anton Protopopov <aspsk@xxxxxxxxxxxxx>
---
include/linux/bpf.h | 30 +++++++++++++++++++++++++++
kernel/bpf/map_iter.c | 48 ++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 77 insertions(+), 1 deletion(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index f58895830ada..20292a096188 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -275,6 +275,7 @@ struct bpf_map {
} owner;
bool bypass_spec_v1;
bool frozen; /* write-once; write-protected by freeze_mutex */
+ s64 __percpu *elements_count;
To avoid corruption on 32 bit archs, should we convert this into local64_t here?
