build error on CONFIG_MEMCG=n "error: invalid use of undefined type 'struct mem_cgroup'"
From: Harry Yoo <hidden>
Date: 2026-01-07 01:57:11
Also in:
linux-mm
On Mon, Jan 05, 2026 at 08:04:22AM -0800, Thomas Ballasi wrote:
quoted hunk ↗ jump to hunk
Memory reclaim events are currently difficult to attribute to specific cgroups, making debugging memory pressure issues challenging. This patch adds memory cgroup ID (memcg_id) to key vmscan tracepoints to enable better correlation and analysis. For operations not associated with a specific cgroup, the field is defaulted to 0. Signed-off-by: Thomas Ballasi <redacted> --- include/trace/events/vmscan.h | 79 ++++++++++++++++++++--------------- mm/shrinker.c | 2 +- mm/vmscan.c | 17 ++++---- 3 files changed, 56 insertions(+), 42 deletions(-)diff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.h index 490958fa10dee..93a9a9ba9405d 100644 --- a/include/trace/events/vmscan.h +++ b/include/trace/events/vmscan.h@@ -208,31 +215,34 @@ TRACE_EVENT(mm_shrink_slab_start, TP_fast_assign( __entry->shr = shr; __entry->shrink = shr->scan_objects; - __entry->nid = sc->nid; __entry->nr_objects_to_shrink = nr_objects_to_shrink; __entry->gfp_flags = (__force unsigned long)sc->gfp_mask; __entry->cache_items = cache_items; __entry->delta = delta; __entry->total_scan = total_scan; __entry->priority = priority; + __entry->nid = sc->nid; + __entry->memcg_id = sc->memcg ? cgroup_id(sc->memcg->css.cgroup) : 0;
Hi Thomas, this is breaking CONFIG_MEMCG=n builds.
In file included from ./include/trace/define_trace.h:132,
from ./include/trace/events/vmscan.h:569,
from mm/vmscan.c:73:
./include/trace/events/vmscan.h: In function ‘do_trace_event_raw_event_mm_shrink_slab_start’:
./include/trace/events/vmscan.h:248:68: error: invalid use of undefined type ‘struct mem_cgroup’
248 | __entry->memcg_id = sc->memcg ? cgroup_id(sc->memcg->css.cgroup) : 0;
| ^~
./include/trace/trace_events.h:427:11: note: in definition of macro ‘__DECLARE_EVENT_CLASS’
427 | { assign; } \
| ^~~~~~
./include/trace/trace_events.h:435:23: note: in expansion of macro ‘PARAMS’
435 | PARAMS(assign), PARAMS(print)) \
| ^~~~~~
./include/trace/trace_events.h:40:9: note: in expansion of macro ‘DECLARE_EVENT_CLASS’
40 | DECLARE_EVENT_CLASS(name, \
| ^~~~~~~~~~~~~~~~~~~
./include/trace/trace_events.h:44:30: note: in expansion of macro ‘PARAMS’
44 | PARAMS(assign), \
| ^~~~~~
./include/trace/events/vmscan.h:214:1: note: in expansion of macro ‘TRACE_EVENT’
214 | TRACE_EVENT(mm_shrink_slab_start,
| ^~~~~~~~~~~
./include/trace/events/vmscan.h:237:9: note: in expansion of macro ‘TP_fast_assign’
237 | TP_fast_assign(
| ^~~~~~~~~~~~~~
./include/trace/events/vmscan.h: In function ‘do_trace_event_raw_event_mm_shrink_slab_end’:
./include/trace/events/vmscan.h:293:56: error: invalid use of undefined type ‘struct mem_cgroup’
293 | __entry->memcg_id = cgroup_id(sc->memcg->css.cgroup);
| ^~
./include/trace/trace_events.h:427:11: note: in definition of macro ‘__DECLARE_EVENT_CLASS’
427 | { assign; } \
| ^~~~~~
./include/trace/trace_events.h:435:23: note: in expansion of macro ‘PARAMS’
435 | PARAMS(assign), PARAMS(print)) \
| ^~~~~~
./include/trace/trace_events.h:40:9: note: in expansion of macro ‘DECLARE_EVENT_CLASS’
40 | DECLARE_EVENT_CLASS(name, \
| ^~~~~~~~~~~~~~~~~~~
./include/trace/trace_events.h:44:30: note: in expansion of macro ‘PARAMS’
44 | PARAMS(assign), \
| ^~~~~~
./include/trace/events/vmscan.h:266:1: note: in expansion of macro ‘TRACE_EVENT’
266 | TRACE_EVENT(mm_shrink_slab_end,
| ^~~~~~~~~~~
./include/trace/events/vmscan.h:285:9: note: in expansion of macro ‘TP_fast_assign’
285 | TP_fast_assign(
| ^~~~~~~~~~~~~~
In file included from ./include/trace/define_trace.h:133:
./include/trace/events/vmscan.h: In function ‘do_perf_trace_mm_shrink_slab_start’:
./include/trace/events/vmscan.h:248:68: error: invalid use of undefined type ‘struct mem_cgroup’
248 | __entry->memcg_id = sc->memcg ? cgroup_id(sc->memcg->css.cgroup) : 0;
| ^~
./include/trace/perf.h:51:11: note: in definition of macro ‘__DECLARE_EVENT_CLASS’
51 | { assign; } \
| ^~~~~~
./include/trace/perf.h:67:23: note: in expansion of macro ‘PARAMS’
67 | PARAMS(assign), PARAMS(print)) \
| ^~~~~~
./include/trace/trace_events.h:40:9: note: in expansion of macro ‘DECLARE_EVENT_CLASS’
40 | DECLARE_EVENT_CLASS(name, \
| ^~~~~~~~~~~~~~~~~~~
./include/trace/trace_events.h:44:30: note: in expansion of macro ‘PARAMS’
44 | PARAMS(assign), \
| ^~~~~~
./include/trace/events/vmscan.h:214:1: note: in expansion of macro ‘TRACE_EVENT’
214 | TRACE_EVENT(mm_shrink_slab_start,
| ^~~~~~~~~~~
./include/trace/events/vmscan.h:237:9: note: in expansion of macro ‘TP_fast_assign’
237 | TP_fast_assign(
| ^~~~~~~~~~~~~~
./include/trace/events/vmscan.h: In function ‘do_perf_trace_mm_shrink_slab_end’:
./include/trace/events/vmscan.h:293:56: error: invalid use of undefined type ‘struct mem_cgroup’
293 | __entry->memcg_id = cgroup_id(sc->memcg->css.cgroup);
| ^~
./include/trace/perf.h:51:11: note: in definition of macro ‘__DECLARE_EVENT_CLASS’
51 | { assign; } \
| ^~~~~~
./include/trace/perf.h:67:23: note: in expansion of macro ‘PARAMS’
67 | PARAMS(assign), PARAMS(print)) \
| ^~~~~~
./include/trace/trace_events.h:40:9: note: in expansion of macro ‘DECLARE_EVENT_CLASS’
40 | DECLARE_EVENT_CLASS(name, \
| ^~~~~~~~~~~~~~~~~~~
./include/trace/trace_events.h:44:30: note: in expansion of macro ‘PARAMS’
44 | PARAMS(assign), \
| ^~~~~~
./include/trace/events/vmscan.h:266:1: note: in expansion of macro ‘TRACE_EVENT’
266 | TRACE_EVENT(mm_shrink_slab_end,
| ^~~~~~~~~~~
./include/trace/events/vmscan.h:285:9: note: in expansion of macro ‘TP_fast_assign’
285 | TP_fast_assign(
| ^~~~~~~~~~~~~~
CC arch/x86/mm/extable.o
make[3]: *** [scripts/Makefile.build:287: mm/vmscan.o] Error 1
make[2]: *** [scripts/Makefile.build:556: mm] Error 2
make[2]: *** Waiting for unfinished jobs....
--
Cheers,
Harry / Hyeonggon
quoted hunk ↗ jump to hunk
), - TP_printk("%pS %p: nid: %d objects to shrink %ld gfp_flags %s cache items %ld delta %lld total_scan %ld priority %d", + TP_printk("%pS %p: nid: %d memcg_id: %u objects to shrink %ld gfp_flags %s cache items %ld delta %lld total_scan %ld priority %d", __entry->shrink, __entry->shr, __entry->nid, + __entry->memcg_id, __entry->nr_objects_to_shrink, show_gfp_flags(__entry->gfp_flags), __entry->cache_items,@@ -242,36 +252,39 @@ TRACE_EVENT(mm_shrink_slab_start, ); TRACE_EVENT(mm_shrink_slab_end, - TP_PROTO(struct shrinker *shr, int nid, int shrinker_retval, + TP_PROTO(struct shrinker *shr, struct shrink_control *sc, int shrinker_retval, long unused_scan_cnt, long new_scan_cnt, long total_scan), - TP_ARGS(shr, nid, shrinker_retval, unused_scan_cnt, new_scan_cnt, + TP_ARGS(shr, sc, shrinker_retval, unused_scan_cnt, new_scan_cnt, total_scan), TP_STRUCT__entry( __field(struct shrinker *, shr) - __field(int, nid) __field(void *, shrink) __field(long, unused_scan) __field(long, new_scan) - __field(int, retval) __field(long, total_scan) + __field(int, nid) + __field(int, retval) + __field(unsigned short, memcg_id) ), TP_fast_assign( __entry->shr = shr; - __entry->nid = nid; __entry->shrink = shr->scan_objects; __entry->unused_scan = unused_scan_cnt; __entry->new_scan = new_scan_cnt; - __entry->retval = shrinker_retval; __entry->total_scan = total_scan; + __entry->nid = sc->nid; + __entry->retval = shrinker_retval; + __entry->memcg_id = cgroup_id(sc->memcg->css.cgroup); ), - TP_printk("%pS %p: nid: %d unused scan count %ld new scan count %ld total_scan %ld last shrinker return val %d", + TP_printk("%pS %p: nid: %d memcg_id: %u unused scan count %ld new scan count %ld total_scan %ld last shrinker return val %d", __entry->shrink, __entry->shr, __entry->nid, + __entry->memcg_id, __entry->unused_scan, __entry->new_scan, __entry->total_scan,@@ -504,9 +517,9 @@ TRACE_EVENT(mm_vmscan_node_reclaim_begin, DEFINE_EVENT(mm_vmscan_direct_reclaim_end_template, mm_vmscan_node_reclaim_end, - TP_PROTO(unsigned long nr_reclaimed), + TP_PROTO(unsigned long nr_reclaimed, unsigned short memcg_id), - TP_ARGS(nr_reclaimed) + TP_ARGS(nr_reclaimed, memcg_id) ); TRACE_EVENT(mm_vmscan_throttled,