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mm, vmscan: enhance mm_vmscan_lru_shrink_inactive tracepoint

mm_vmscan_lru_shrink_inactive will currently report the number of scanned and reclaimed pages. This doesn't give us an idea how the reclaim went except for the overall effectiveness though. Export and show other counters which will tell us why we couldn't reclaim some pages. - nr_dirty, nr_writeback, nr_congested and nr_immediate tells us how many pages are blocked due to IO - nr_activate tells us how many pages were moved to the active list - nr_ref_keep reports how many pages are kept on the LRU due to references (mostly for the file pages which are about to go for another round through the inactive list) - nr_unmap_fail - how many pages failed to unmap All these are rather low level so they might change in future but the tracepoint is already implementation specific so no tools should be depending on its stability.

Michal Hocko committed 9 years ago

Commit 5bccd161 parent 3c710c12 files · +40 −3Browse files

Showing the changes to include/trace (1 of 2 files). Show all

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include/trace/events/vmscan.h+26−3
@@ -340,14 +340,27 @@ TRACE_EVENT(mm_vmscan_lru_shrink_inactive, · 339 unmodified lines
340340
341341 TP_PROTO(int nid,
342342 unsigned long nr_scanned, unsigned long nr_reclaimed,
343+ unsigned long nr_dirty, unsigned long nr_writeback,
344+ unsigned long nr_congested, unsigned long nr_immediate,
345+ unsigned long nr_activate, unsigned long nr_ref_keep,
346+ unsigned long nr_unmap_fail,
343347 int priority, int file),
344348
345− TP_ARGS(nid, nr_scanned, nr_reclaimed, priority, file),
349+ TP_ARGS(nid, nr_scanned, nr_reclaimed, nr_dirty, nr_writeback,
350+ nr_congested, nr_immediate, nr_activate, nr_ref_keep,
351+ nr_unmap_fail, priority, file),
346352
347353 TP_STRUCT__entry(
348354 __field(int, nid)
349355 __field(unsigned long, nr_scanned)
350356 __field(unsigned long, nr_reclaimed)
357+ __field(unsigned long, nr_dirty)
358+ __field(unsigned long, nr_writeback)
359+ __field(unsigned long, nr_congested)
360+ __field(unsigned long, nr_immediate)
361+ __field(unsigned long, nr_activate)
362+ __field(unsigned long, nr_ref_keep)
363+ __field(unsigned long, nr_unmap_fail)
351364 __field(int, priority)
352365 __field(int, reclaim_flags)
353366 ),
@@ -356,14 +369,24 @@ TRACE_EVENT(mm_vmscan_lru_shrink_inactive, · 2 unmodified lines
356369 __entry->nid = nid;
357370 __entry->nr_scanned = nr_scanned;
358371 __entry->nr_reclaimed = nr_reclaimed;
372+ __entry->nr_dirty = nr_dirty;
373+ __entry->nr_writeback = nr_writeback;
374+ __entry->nr_congested = nr_congested;
375+ __entry->nr_immediate = nr_immediate;
376+ __entry->nr_activate = nr_activate;
377+ __entry->nr_ref_keep = nr_ref_keep;
378+ __entry->nr_unmap_fail = nr_unmap_fail;
359379 __entry->priority = priority;
360380 __entry->reclaim_flags = trace_shrink_flags(file);
361381 ),
362382
363− TP_printk("nid=%d nr_scanned=%ld nr_reclaimed=%ld priority=%d flags=%s",
383+ TP_printk("nid=%d nr_scanned=%ld nr_reclaimed=%ld nr_dirty=%ld nr_writeback=%ld nr_congested=%ld nr_immediate=%ld nr_activate=%ld nr_ref_keep=%ld nr_unmap_fail=%ld priority=%d flags=%s",
364384 __entry->nid,
365385 __entry->nr_scanned, __entry->nr_reclaimed,
366− __entry->priority,
386+ __entry->nr_dirty, __entry->nr_writeback,
387+ __entry->nr_congested, __entry->nr_immediate,
388+ __entry->nr_activate, __entry->nr_ref_keep,
389+ __entry->nr_unmap_fail, __entry->priority,
367390 show_reclaim_flags(__entry->reclaim_flags))
368391 );
369392

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