Thread (3 messages) 3 messages, 2 authors, 2023-09-26

RE: [PATCH v3] vmscan: add trace events for lru_gen

From: 김재원 <hidden>
Date: 2023-09-26 02:11:17
Also in: linux-mm, lkml
Subsystem: memory management, memory management - mglru (multi-gen lru), memory management - reclaim, the rest, tracing · Maintainers: Andrew Morton, Johannes Weiner, Linus Torvalds, Steven Rostedt, Masami Hiramatsu

Hello,

On Sun, 24 Sep 2023 23:23:43 +0900 Jaewon Kim [off-list ref] wrote:
quoted
As the legacy lru provides, the lru_gen needs some trace events for
debugging.

This commit introduces 2 trace events.
  trace_mm_vmscan_lru_gen_scan
  trace_mm_vmscan_lru_gen_evict

Each event is similar to the following legacy events.
  trace_mm_vmscan_lru_isolate,
  trace_mm_vmscan_lru_shrink_[in]active

Here's an example
  mm_vmscan_lru_gen_scan: isolate_mode=0 classzone=1 order=9 nr_requested=4096 nr_scanned=431 nr_skipped=0 nr_taken=55 lru=anon
  mm_vmscan_lru_gen_evict: nid=0 nr_reclaimed=42 nr_dirty=0 nr_writeback=0 nr_congested=0 nr_immediate=0 nr_activate_anon=13 nr_activate_file=0 nr_ref_keep=0 nr_unmap_fail=0 priority=2 flags=RECLAIM_WB_ANON|RECLAIM_WB_ASYNC
  mm_vmscan_lru_gen_scan: isolate_mode=0 classzone=1 order=9 nr_requested=4096 nr_scanned=66 nr_skipped=0 nr_taken=64 lru=file
  mm_vmscan_lru_gen_evict: nid=0 nr_reclaimed=62 nr_dirty=0 nr_writeback=0 nr_congested=0 nr_immediate=0 nr_activate_anon=0 nr_activate_file=2 nr_ref_keep=0 nr_unmap_fail=0 priority=2 flags=RECLAIM_WB_FILE|RECLAIM_WB_ASYNC

Signed-off-by: Jaewon Kim <redacted>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Reviewed-by: T.J. Mercier <tjmercier@google.com>
---
v3: change printk format
v2: use condition and make it aligned
v1: introduce trace events
---
 include/trace/events/mmflags.h |  5 ++
 include/trace/events/vmscan.h  | 98 ++++++++++++++++++++++++++++++++++
 mm/vmscan.c                    | 17 ++++--
 3 files changed, 115 insertions(+), 5 deletions(-)
diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h
index 1478b9dd05fa..44e9b38f83e7 100644
--- a/include/trace/events/mmflags.h
+++ b/include/trace/events/mmflags.h
@@ -274,6 +274,10 @@ IF_HAVE_VM_SOFTDIRTY(VM_SOFTDIRTY,	"softdirty"	)		\
 		EM (LRU_ACTIVE_FILE, "active_file") \
 		EMe(LRU_UNEVICTABLE, "unevictable")
 
+#define LRU_GEN_NAMES		\
+		EM (LRU_GEN_ANON, "anon") \
+		EMe(LRU_GEN_FILE, "file")
+
I found this patchset makes build fails when !CONFIG_LRU_GEN, like below:

   In file included from /linux/include/trace/trace_events.h:27,
                    from /linux/include/trace/define_trace.h:102,
                    from /linux/include/trace/events/oom.h:195,
                    from /linux/mm/oom_kill.c:53:
   /linux/include/trace/events/mmflags.h:278:7: error: ‘LRU_GEN_ANON’ undeclared here (not in a function); did you mean ‘LRU_GEN_PGOFF’?
     278 |   EM (LRU_GEN_ANON, "anon") \
         |       ^~~~~~~~~~~~

Maybe some config checks are needed?
Sorry and thank you for your comment.
I think I need to wrap with CONFIG_LRU_GEN
Adding #ifdef CONFIG_LRU_GEN even to vmscan.c seems not nice though.

Additionally I had to remove isolate_mode to be compatible with
mm, vmscan: remove ISOLATE_UNMAPPED
https://lore.kernel.org/linux-mm/20230914131637.12204-4-vbabka@suse.cz/ (local)

Here's what I changed on top of this v3 patch.
I'm trying to find a way not to use ifdef CONFIG_LRU_GEN in vmscan.c


--- a/include/trace/events/mmflags.h
+++ b/include/trace/events/mmflags.h
@@ -274,9 +274,11 @@ IF_HAVE_VM_SOFTDIRTY(VM_SOFTDIRTY, "softdirty"     )               \
                EM (LRU_ACTIVE_FILE, "active_file") \
                EMe(LRU_UNEVICTABLE, "unevictable")
 
+#ifdef CONFIG_LRU_GEN
 #define LRU_GEN_NAMES          \
                EM (LRU_GEN_ANON, "anon") \
                EMe(LRU_GEN_FILE, "file")
+#endif
 
 /*
  * First define the enums in the above macros to be exported to userspace
@@ -292,7 +294,9 @@ COMPACTION_PRIORITY
 /* COMPACTION_FEEDBACK are defines not enums. Not needed here. */
 ZONE_TYPE
 LRU_NAMES
+#ifdef CONFIG_LRU_GEN
 LRU_GEN_NAMES
+#endif
 
 /*
  * Now redefine the EM() and EMe() macros to map the enums to the strings
diff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.h
index e7230fa8bda1..ba99182d6558 100644
--- a/include/trace/events/vmscan.h
+++ b/include/trace/events/vmscan.h
@@ -323,6 +323,7 @@ TRACE_EVENT(mm_vmscan_lru_isolate,
                __print_symbolic(__entry->lru, LRU_NAMES))
 );
 
+#ifdef CONFIG_LRU_GEN
 TRACE_EVENT_CONDITION(mm_vmscan_lru_gen_scan,
        TP_PROTO(int highest_zoneidx,
                int order,
@@ -330,10 +331,9 @@ TRACE_EVENT_CONDITION(mm_vmscan_lru_gen_scan,
                unsigned long nr_scanned,
                unsigned long nr_skipped,
                unsigned long nr_taken,
-               isolate_mode_t isolate_mode,
                int lru),
 
-       TP_ARGS(highest_zoneidx, order, nr_requested, nr_scanned, nr_skipped, nr_taken, isolate_mode, lru),
+       TP_ARGS(highest_zoneidx, order, nr_requested, nr_scanned, nr_skipped, nr_taken, lru),
 
        TP_CONDITION(nr_scanned),
 
@@ -344,7 +344,6 @@ TRACE_EVENT_CONDITION(mm_vmscan_lru_gen_scan,
                __field(unsigned long, nr_scanned)
                __field(unsigned long, nr_skipped)
                __field(unsigned long, nr_taken)
-               __field(unsigned int, isolate_mode)
                __field(int, lru)
        ),
 
@@ -355,7 +354,6 @@ TRACE_EVENT_CONDITION(mm_vmscan_lru_gen_scan,
                __entry->nr_scanned = nr_scanned;
                __entry->nr_skipped = nr_skipped;
                __entry->nr_taken = nr_taken;
-               __entry->isolate_mode = (__force unsigned int)isolate_mode;
                __entry->lru = lru;
        ),
 
@@ -363,7 +361,7 @@ TRACE_EVENT_CONDITION(mm_vmscan_lru_gen_scan,
         * classzone is previous name of the highest_zoneidx.
         * Reason not to change it is the ABI requirement of the tracepoint.
         */
-       TP_printk("isolate_mode=%u classzone=%d order=%d nr_requested=%lu nr_scanned=%lu nr_skipped=%lu nr_taken=%lu lru=%s",
+       TP_printk("classzone=%d order=%d nr_requested=%lu nr_scanned=%lu nr_skipped=%lu nr_taken=%lu lru=%s",
                __entry->isolate_mode,
                __entry->highest_zoneidx,
                __entry->order,
@@ -373,6 +371,7 @@ TRACE_EVENT_CONDITION(mm_vmscan_lru_gen_scan,
                __entry->nr_taken,
                __print_symbolic(__entry->lru, LRU_GEN_NAMES))
 );
+#endif
 
 TRACE_EVENT(mm_vmscan_write_folio,
 
@@ -484,6 +483,7 @@ TRACE_EVENT(mm_vmscan_lru_shrink_active,
                show_reclaim_flags(__entry->reclaim_flags))
 );
 
+#ifdef CONFIG_LRU_GEN
 TRACE_EVENT(mm_vmscan_lru_gen_evict,
 
        TP_PROTO(int nid, unsigned long nr_reclaimed,
@@ -530,6 +530,7 @@ TRACE_EVENT(mm_vmscan_lru_gen_evict,
                __entry->priority,
                show_reclaim_flags(__entry->reclaim_flags))
 );
+#endif
 
 TRACE_EVENT(mm_vmscan_node_reclaim_begin,
 
diff --git a/mm/vmscan.c b/mm/vmscan.c
index dbfacf79b42c..d26e1d2610ca 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -4390,9 +4390,10 @@ static int scan_folios(struct lruvec *lruvec, struct scan_control *sc,
        __count_memcg_events(memcg, PGREFILL, sorted);
        __count_vm_events(PGSCAN_ANON + type, isolated);
 
+#ifdef CONFIG_LRU_GEN
        trace_mm_vmscan_lru_gen_scan(sc->reclaim_idx, sc->order, MAX_LRU_BATCH,
-                       scanned, skipped, isolated,
-                       sc->may_unmap ? 0 : ISOLATE_UNMAPPED, type);
+                       scanned, skipped, isolated, type);
+#endif
        /*
         * There might not be eligible folios due to reclaim_idx. Check the
         * remaining to prevent livelock if it's not making progress.
@@ -4522,8 +4523,10 @@ static int evict_folios(struct lruvec *lruvec, struct scan_control *sc, int swap
 retry:
        reclaimed = shrink_folio_list(&list, pgdat, sc, &stat, false);
        sc->nr_reclaimed += reclaimed;
+#ifdef CONFIG_LRU_GEN
        trace_mm_vmscan_lru_gen_evict(pgdat->node_id, reclaimed, &stat,
                                      sc->priority, type);
+#endif
 
        list_for_each_entry_safe_reverse(folio, next, &list, lru) {
                if (!folio_evictable(folio)) {

Thank you

Thanks,
SJ
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