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4221aadd72
Vmscan has six main reclaim entry points: try_to_free_pages() for direct reclaim, try_to_free_mem_cgroup_pages() for memcg reclaim, mem_cgroup_shrink_node() for memcg soft limit reclaim, node_reclaim() for node reclaim, shrink_all_memory() for hibernation reclaim, and balance_pgdat() for kswapd reclaim. All of them, except for shrink_all_memory() and balance_pgdat(), already have begin/end tracepoints. This makes it harder to trace which reclaim path is responsible for memory reclaim activity, because kswapd reclaim cannot be identified as cleanly as other reclaim entry points, even though it is the main background reclaim path under memory pressure. There may be no need to trace shrink_all_memory() as it is primarily used during hibernation. So this patch adds the missing tracepoint pair for balance_pgdat(). The begin tracepoint records the node id, requested reclaim order, and the requested classzone bound (highest_zoneidx). The end tracepoint records the node id, the reclaim order that balance_pgdat() finished with, the requested classzone bound, and nr_reclaimed. Together, they show the requested reclaim order and classzone bound, whether reclaim fell back to a lower order, and how much reclaim work was done. The end tracepoint also records highest_zoneidx even though it does not change within a balance_pgdat() invocation. This keeps the end event self-contained, so users can analyze reclaim results directly from end events without depending on begin/end correlation, which is less convenient when tracing is filtered or records are dropped. It also makes it straightforward to relate nr_reclaimed and the final reclaim order to the requested classzone bound. Link: https://lore.kernel.org/20260424031418.174597-1-b.suvonov@sjtu.edu.cn Link: https://lore.kernel.org/20260423103753.546582-1-b.suvonov@sjtu.edu.cn Signed-off-by: Bunyod Suvonov <b.suvonov@sjtu.edu.cn> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Barry Song <baohua@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kairui Song <kasong@tencent.com> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Wei Xu <weixugc@google.com> Cc: Yuanchu Xie <yuanchu@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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| .. | ||
| events | ||
| misc | ||
| stages | ||
| bpf_probe.h | ||
| define_custom_trace.h | ||
| define_remote_events.h | ||
| define_trace.h | ||
| perf.h | ||
| syscall.h | ||
| trace_custom_events.h | ||
| trace_events.h | ||