[PATCH RFC v3 0/7] mm/vmscan: move vmscan tracepoints to a local header

[PATCH RFC v3 0/7] mm/vmscan: move vmscan tracepoints to a local header

[Ridong Chen]

From: Ridong Chen <chenridong@xiaomi.com>

This series started as an effort to add two tracepoints for MGLRU. In the
discussion, Steven suggested moving include/trace/events/vmscan.h to
mm/trace_vmscan.h [1], as several other subsystems already do. Once the
header lives under mm/, struct scan_control can be moved there too, letting
the trace events access its fields directly instead of having each callsite
copy the scalars out by hand.

The series builds in small steps:

  1) drop the unused vmscan trace include from memcontrol.c;
  2) move include/trace/events/vmscan.h to mm/trace_vmscan.h, using a
     relative TRACE_INCLUDE_PATH so no Makefile change is needed;
  3) move struct scan_control into a dedicated mm/vmscan.h, which
     trace_vmscan.h pulls in, guarded against the multi-read that
     define_trace.h performs;
  4-7) pass scan_control to the vmscan tracepoints and pick the fields
     out in TP_fast_assign, one group at a time: the reclaim-begin
     events, the LRU isolate/shrink events, mm_vmscan_reclaim_pages and
     mm_vmscan_balance_pgdat_end.

Besides the cleanup, this moves the loads of the tracepoint arguments out
of the reclaim paths and into the trace event callbacks, which only run
when the event is enabled. On x86_64 with gcc 11.4, the callers in
mm/vmscan.o shrink accordingly (bytes), e.g.:

  isolate_lru_folios    4060 -> 3896 (-164)
  __node_reclaim        2258 -> 2076 (-182)
  isolate_folios        8706 -> 8577 (-129)
  shrink_active_list    3669 -> 3544 (-125)
  evict_folios          4787 -> 4698  (-89)

There is no functional change. TP_STRUCT__entry and TP_printk are
untouched, so the tracefs event format is identical. This was confirmed
by diffing the tracefs format files before and after, and by capturing
the direct/memcg/node reclaim-begin events under load in a QEMU guest
(order, gfp_flags and memcg_id all match). BPF programs attached via
raw_tp/tp_btf do see the new TP_PROTO and need to be adjusted;
tracepoints are not a stable ABI (see Documentation/bpf/bpf_design_QA.rst).

highest_zoneidx and nr_reclaimed stay separate arguments: the former is
a balance_pgdat() parameter (sc.reclaim_idx may differ from it by the
time the end event fires), and the latter is the return value of
shrink_folio_list(), which does not update sc->nr_reclaimed.

[1]: https://lore.kernel.org/linux-mm/20260916095122.50cbb620@robin/

---
Changes in RFC v3:
  - Use "Assisted-by: LLM" (Muchun).
  - Note the BPF raw_tp/tp_btf impact in the changelogs (Sashiko).
  - Changelog wording fixes and minor indentation fixes.
  - Link to RFC v2: https://lore.kernel.org/all/20260928114625.3609130-1-ridong.chen@linux.dev/

Changes in RFC v2:
  - Convert the remaining vmscan tracepoints too.
  - Move struct scan_control to mm/vmscan.h (Baoquan).

Ridong Chen (7):
  mm/memcontrol: drop unused vmscan tracepoint include
  mm/vmscan: move vmscan tracepoints to a local header
  mm/vmscan: move struct scan_control to a dedicated header
  mm/vmscan: pass scan_control to the reclaim-begin tracepoints
  mm/vmscan: pass scan_control to the LRU isolate/shrink tracepoints
  mm/vmscan: pass scan_control to mm_vmscan_reclaim_pages
  mm/vmscan: pass scan_control to mm_vmscan_balance_pgdat_end

 MAINTAINERS                                   |   4 +
 mm/memcontrol.c                               |   2 -
 mm/shrinker.c                                 |   2 +-
 .../events/vmscan.h => mm/trace_vmscan.h      |  80 ++++++-----
 mm/vmscan.c                                   | 136 ++----------------
 mm/vmscan.h                                   | 118 +++++++++++++++
 6 files changed, 178 insertions(+), 164 deletions(-)
 rename include/trace/events/vmscan.h => mm/trace_vmscan.h (90%)
 create mode 100644 mm/vmscan.h


base-commit: 4eb2586bd40db27d77cc5b724ca9386ed0c71d53
-- 
2.34.1

[PATCH RFC v3 1/7] mm/memcontrol: drop unused vmscan tracepoint include

[Ridong Chen]

From: Ridong Chen <chenridong@xiaomi.com>

memcontrol.c includes <trace/events/vmscan.h> but does not use any of
the tracepoints or macros it defines: all tracepoints invoked here come
from memcg.h and writeback.h.

Drop it ahead of moving the vmscan trace header under mm/, after which
<trace/events/vmscan.h> will no longer exist.

No functional change.

Assisted-by: LLM
Acked-by: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Ridong Chen <chenridong@xiaomi.com>
---
 mm/memcontrol.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index aad0498a7bd6..95c2322d4a6f 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -77,8 +77,6 @@
 #include <trace/events/memcg.h>
 #undef CREATE_TRACE_POINTS
 
-#include <trace/events/vmscan.h>
-
 struct cgroup_subsys memory_cgrp_subsys __read_mostly;
 EXPORT_SYMBOL(memory_cgrp_subsys);
 
-- 
2.34.1

[PATCH RFC v3 2/7] mm/vmscan: move vmscan tracepoints to a local header

[Ridong Chen]

From: Ridong Chen <chenridong@xiaomi.com>

Move include/trace/events/vmscan.h to mm/trace_vmscan.h so that the
tracepoints can be extended to reference vmscan-internal structures such
as struct scan_control, which is not visible outside mm/.  This mirrors
what several other subsystems already do with their trace headers (e.g.
arch/x86/kvm/trace.h, drivers/gpu/drm/drm_trace.h, net/xfrm/trace_iptfs.h).
As they do, use a relative TRACE_INCLUDE_PATH so that no Makefile change
is needed.

No functional change.

Assisted-by: LLM
Signed-off-by: Ridong Chen <chenridong@xiaomi.com>
---
 MAINTAINERS                                        | 2 ++
 mm/shrinker.c                                      | 2 +-
 include/trace/events/vmscan.h => mm/trace_vmscan.h | 4 ++++
 mm/vmscan.c                                        | 2 +-
 4 files changed, 8 insertions(+), 2 deletions(-)
 rename include/trace/events/vmscan.h => mm/trace_vmscan.h (99%)

diff --git a/MAINTAINERS b/MAINTAINERS
index c5519d67b6f4..80d2a9dd0525 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17575,6 +17575,7 @@ F:	Documentation/admin-guide/mm/multigen_lru.rst
 F:	Documentation/mm/multigen_lru.rst
 F:	include/linux/mm_inline.h
 F:	include/linux/mmzone.h
+F:	mm/trace_vmscan.h
 F:	mm/vmscan.c
 F:	mm/workingset.c
 
@@ -17722,6 +17723,7 @@ R:	Shakeel Butt <shakeel.butt@linux.dev>
 R:	Lorenzo Stoakes <ljs@kernel.org>
 L:	linux-mm@kvack.org
 S:	Maintained
+F:	mm/trace_vmscan.h
 F:	mm/vmscan.c
 F:	mm/workingset.c
 
diff --git a/mm/shrinker.c b/mm/shrinker.c
index 7ec2a9704f6f..3c3e87c4b61c 100644
--- a/mm/shrinker.c
+++ b/mm/shrinker.c
@@ -3,7 +3,7 @@
 #include <linux/rwsem.h>
 #include <linux/shrinker.h>
 #include <linux/rculist.h>
-#include <trace/events/vmscan.h>
+#include "trace_vmscan.h"
 
 #include "internal.h"
 
diff --git a/include/trace/events/vmscan.h b/mm/trace_vmscan.h
similarity index 99%
rename from include/trace/events/vmscan.h
rename to mm/trace_vmscan.h
index 8a872990b4be..c5d824fef554 100644
--- a/include/trace/events/vmscan.h
+++ b/mm/trace_vmscan.h
@@ -648,4 +648,8 @@ TRACE_EVENT(mm_vmscan_kswapd_clear_hopeless,
 #endif /* _TRACE_VMSCAN_H */
 
 /* This part must be outside protection */
+#undef TRACE_INCLUDE_FILE
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH ../../mm
+#define TRACE_INCLUDE_FILE trace_vmscan
 #include <trace/define_trace.h>
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 29b31446fc11..6207dad9e644 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -71,7 +71,7 @@
 #include "swap.h"
 
 #define CREATE_TRACE_POINTS
-#include <trace/events/vmscan.h>
+#include "trace_vmscan.h"
 
 struct scan_control {
 	/* How many pages shrink_list() should reclaim */
-- 
2.34.1

[PATCH RFC v3 3/7] mm/vmscan: move struct scan_control to a dedicated header

[Ridong Chen]

From: Ridong Chen <chenridong@xiaomi.com>

The definition of struct scan_control has lived inline at the top of
mm/vmscan.c. Move it out to a new mm/vmscan.h so the reclaim-internal
state can be referenced from other reclaim translation units without
duplicating the definition.

The header uses an ordinary include guard and pulls in only what the
struct needs (nodemask_t, gfp_t and struct reclaim_state).

mm/trace_vmscan.h includes the new header directly so that any
translation unit pulling in the trace events (mm/vmscan.c, mm/shrinker.c)
sees the full definition of struct scan_control regardless of include
order.

No functional change.

Assisted-by: LLM
Signed-off-by: Ridong Chen <chenridong@xiaomi.com>
---
 MAINTAINERS       |   2 +
 mm/trace_vmscan.h |   2 +
 mm/vmscan.c       | 108 ------------------------------------------
 mm/vmscan.h       | 118 ++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 122 insertions(+), 108 deletions(-)
 create mode 100644 mm/vmscan.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 80d2a9dd0525..1f2d7dcbfd1b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17577,6 +17577,7 @@ F:	include/linux/mm_inline.h
 F:	include/linux/mmzone.h
 F:	mm/trace_vmscan.h
 F:	mm/vmscan.c
+F:	mm/vmscan.h
 F:	mm/workingset.c
 
 MEMORY MANAGEMENT - MIGRATION
@@ -17725,6 +17726,7 @@ L:	linux-mm@kvack.org
 S:	Maintained
 F:	mm/trace_vmscan.h
 F:	mm/vmscan.c
+F:	mm/vmscan.h
 F:	mm/workingset.c
 
 MEMORY MANAGEMENT - RMAP (REVERSE MAPPING)
diff --git a/mm/trace_vmscan.h b/mm/trace_vmscan.h
index c5d824fef554..91fb1c30dd46 100644
--- a/mm/trace_vmscan.h
+++ b/mm/trace_vmscan.h
@@ -11,6 +11,8 @@
 #include <linux/memcontrol.h>
 #include <trace/events/mmflags.h>
 
+#include "vmscan.h"
+
 #define RECLAIM_WB_ANON		0x0001u
 #define RECLAIM_WB_FILE		0x0002u
 #define RECLAIM_WB_MIXED	0x0010u
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 6207dad9e644..ab118f6b32eb 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -73,114 +73,6 @@
 #define CREATE_TRACE_POINTS
 #include "trace_vmscan.h"
 
-struct scan_control {
-	/* How many pages shrink_list() should reclaim */
-	unsigned long nr_to_reclaim;
-
-	/*
-	 * Nodemask of nodes allowed by the caller. If NULL, all nodes
-	 * are scanned.
-	 */
-	const nodemask_t *nodemask;
-
-	/*
-	 * The memory cgroup that hit its limit and as a result is the
-	 * primary target of this reclaim invocation.
-	 */
-	struct mem_cgroup *target_mem_cgroup;
-
-	/*
-	 * Scan pressure balancing between anon and file LRUs
-	 */
-	unsigned long	anon_cost;
-	unsigned long	file_cost;
-
-	/* Swappiness value for proactive reclaim. Always use sc_swappiness()! */
-	int *proactive_swappiness;
-
-	/* Can active folios be deactivated as part of reclaim? */
-#define DEACTIVATE_ANON 1
-#define DEACTIVATE_FILE 2
-	unsigned int may_deactivate:2;
-	unsigned int force_deactivate:1;
-	unsigned int skipped_deactivate:1;
-
-	/* zone_reclaim_mode, boost reclaim */
-	unsigned int may_writepage:1;
-
-	/* zone_reclaim_mode */
-	unsigned int may_unmap:1;
-
-	/* zone_reclaim_mode, boost reclaim, cgroup restrictions */
-	unsigned int may_swap:1;
-
-	/* Not allow cache_trim_mode to be turned on as part of reclaim? */
-	unsigned int no_cache_trim_mode:1;
-
-	/* Has cache_trim_mode failed at least once? */
-	unsigned int cache_trim_mode_failed:1;
-
-	/* Proactive reclaim invoked by userspace */
-	unsigned int proactive:1;
-
-	/*
-	 * Cgroup memory below memory.low is protected as long as we
-	 * don't threaten to OOM. If any cgroup is reclaimed at
-	 * reduced force or passed over entirely due to its memory.low
-	 * setting (memcg_low_skipped), and nothing is reclaimed as a
-	 * result, then go back for one more cycle that reclaims the protected
-	 * memory (memcg_low_reclaim) to avert OOM.
-	 */
-	unsigned int memcg_low_reclaim:1;
-	unsigned int memcg_low_skipped:1;
-
-	/* Shared cgroup tree walk failed, rescan the whole tree */
-	unsigned int memcg_full_walk:1;
-
-	unsigned int hibernation_mode:1;
-
-	/* One of the zones is ready for compaction */
-	unsigned int compaction_ready:1;
-
-	/* There is easily reclaimable cold cache in the current node */
-	unsigned int cache_trim_mode:1;
-
-	/* The file folios on the current node are dangerously low */
-	unsigned int file_is_tiny:1;
-
-	/* Always discard instead of demoting to lower tier memory */
-	unsigned int no_demotion:1;
-
-	/* Allocation order */
-	s8 order;
-
-	/* Scan (total_size >> priority) pages at once */
-	s8 priority;
-
-	/* The highest zone to isolate folios for reclaim from */
-	s8 reclaim_idx;
-
-	/* This context's GFP mask */
-	gfp_t gfp_mask;
-
-	/* Incremented by the number of inactive pages that were scanned */
-	unsigned long nr_scanned;
-
-	/* Number of pages freed so far during a call to shrink_zones() */
-	unsigned long nr_reclaimed;
-
-	struct {
-		unsigned int dirty;
-		unsigned int congested;
-		unsigned int writeback;
-		unsigned int immediate;
-		unsigned int taken;
-	} nr;
-
-	/* for recording the reclaimed slab by now */
-	struct reclaim_state reclaim_state;
-};
-
 #ifdef ARCH_HAS_PREFETCHW
 static inline void prefetchw_prev_lru_folio(struct folio *folio,
 		struct list_head *base)
diff --git a/mm/vmscan.h b/mm/vmscan.h
new file mode 100644
index 000000000000..adb22e80d760
--- /dev/null
+++ b/mm/vmscan.h
@@ -0,0 +1,118 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _MM_VMSCAN_H
+#define _MM_VMSCAN_H
+
+#include <linux/gfp_types.h>
+#include <linux/nodemask.h>
+#include <linux/swap.h>
+#include <linux/types.h>
+
+struct scan_control {
+	/* How many pages shrink_list() should reclaim */
+	unsigned long nr_to_reclaim;
+
+	/*
+	 * Nodemask of nodes allowed by the caller. If NULL, all nodes
+	 * are scanned.
+	 */
+	const nodemask_t *nodemask;
+
+	/*
+	 * The memory cgroup that hit its limit and as a result is the
+	 * primary target of this reclaim invocation.
+	 */
+	struct mem_cgroup *target_mem_cgroup;
+
+	/*
+	 * Scan pressure balancing between anon and file LRUs
+	 */
+	unsigned long	anon_cost;
+	unsigned long	file_cost;
+
+	/* Swappiness value for proactive reclaim. Always use sc_swappiness()! */
+	int *proactive_swappiness;
+
+	/* Can active folios be deactivated as part of reclaim? */
+#define DEACTIVATE_ANON 1
+#define DEACTIVATE_FILE 2
+	unsigned int may_deactivate:2;
+	unsigned int force_deactivate:1;
+	unsigned int skipped_deactivate:1;
+
+	/* zone_reclaim_mode, boost reclaim */
+	unsigned int may_writepage:1;
+
+	/* zone_reclaim_mode */
+	unsigned int may_unmap:1;
+
+	/* zone_reclaim_mode, boost reclaim, cgroup restrictions */
+	unsigned int may_swap:1;
+
+	/* Not allow cache_trim_mode to be turned on as part of reclaim? */
+	unsigned int no_cache_trim_mode:1;
+
+	/* Has cache_trim_mode failed at least once? */
+	unsigned int cache_trim_mode_failed:1;
+
+	/* Proactive reclaim invoked by userspace */
+	unsigned int proactive:1;
+
+	/*
+	 * Cgroup memory below memory.low is protected as long as we
+	 * don't threaten to OOM. If any cgroup is reclaimed at
+	 * reduced force or passed over entirely due to its memory.low
+	 * setting (memcg_low_skipped), and nothing is reclaimed as a
+	 * result, then go back for one more cycle that reclaims the protected
+	 * memory (memcg_low_reclaim) to avert OOM.
+	 */
+	unsigned int memcg_low_reclaim:1;
+	unsigned int memcg_low_skipped:1;
+
+	/* Shared cgroup tree walk failed, rescan the whole tree */
+	unsigned int memcg_full_walk:1;
+
+	unsigned int hibernation_mode:1;
+
+	/* One of the zones is ready for compaction */
+	unsigned int compaction_ready:1;
+
+	/* There is easily reclaimable cold cache in the current node */
+	unsigned int cache_trim_mode:1;
+
+	/* The file folios on the current node are dangerously low */
+	unsigned int file_is_tiny:1;
+
+	/* Always discard instead of demoting to lower tier memory */
+	unsigned int no_demotion:1;
+
+	/* Allocation order */
+	s8 order;
+
+	/* Scan (total_size >> priority) pages at once */
+	s8 priority;
+
+	/* The highest zone to isolate folios for reclaim from */
+	s8 reclaim_idx;
+
+	/* This context's GFP mask */
+	gfp_t gfp_mask;
+
+	/* Incremented by the number of inactive pages that were scanned */
+	unsigned long nr_scanned;
+
+	/* Number of pages freed so far during a call to shrink_zones() */
+	unsigned long nr_reclaimed;
+
+	struct {
+		unsigned int dirty;
+		unsigned int congested;
+		unsigned int writeback;
+		unsigned int immediate;
+		unsigned int taken;
+	} nr;
+
+	/* for recording the reclaimed slab by now */
+	struct reclaim_state reclaim_state;
+};
+
+#endif /* _MM_VMSCAN_H */
-- 
2.34.1

[PATCH RFC v3 4/7] mm/vmscan: pass scan_control to the reclaim-begin tracepoints

[Ridong Chen]

From: Ridong Chen <chenridong@xiaomi.com>

The reclaim-begin tracepoints describe the entry conditions of a reclaim
invocation, which struct scan_control already carries. Now that the struct
is visible from the trace header, pass sc directly and pick the fields out
in TP_fast_assign instead of spelling out gfp_mask and order at every
callsite.

No functional change. The tracefs event format (TP_STRUCT__entry and
TP_printk) is unchanged, so tracefs-based consumers are unaffected.
BPF programs attached via raw_tp/tp_btf see the new TP_PROTO and need
to be adjusted; tracepoints are not a stable ABI (see
Documentation/bpf/bpf_design_QA.rst).

Assisted-by: LLM
Signed-off-by: Ridong Chen <chenridong@xiaomi.com>
---
 mm/trace_vmscan.h | 24 ++++++++++++------------
 mm/vmscan.c       |  7 +++----
 2 files changed, 15 insertions(+), 16 deletions(-)

diff --git a/mm/trace_vmscan.h b/mm/trace_vmscan.h
index 91fb1c30dd46..28561fda83b3 100644
--- a/mm/trace_vmscan.h
+++ b/mm/trace_vmscan.h
@@ -178,9 +178,9 @@ TRACE_EVENT(mm_vmscan_wakeup_kswapd,
 
 DECLARE_EVENT_CLASS(mm_vmscan_direct_reclaim_begin_template,
 
-	TP_PROTO(gfp_t gfp_flags, int order, struct mem_cgroup *memcg),
+	TP_PROTO(struct scan_control *sc, struct mem_cgroup *memcg),
 
-	TP_ARGS(gfp_flags, order, memcg),
+	TP_ARGS(sc, memcg),
 
 	TP_STRUCT__entry(
 		__field(	unsigned long,	gfp_flags	)
@@ -189,8 +189,8 @@ DECLARE_EVENT_CLASS(mm_vmscan_direct_reclaim_begin_template,
 	),
 
 	TP_fast_assign(
-		__entry->gfp_flags	= (__force unsigned long)gfp_flags;
-		__entry->order		= order;
+		__entry->gfp_flags	= (__force unsigned long)sc->gfp_mask;
+		__entry->order		= sc->order;
 		__entry->memcg_id	= mem_cgroup_id(memcg);
 	),
 
@@ -204,17 +204,17 @@ DECLARE_EVENT_CLASS(mm_vmscan_direct_reclaim_begin_template,
 
 DEFINE_EVENT(mm_vmscan_direct_reclaim_begin_template, mm_vmscan_direct_reclaim_begin,
 
-	TP_PROTO(gfp_t gfp_flags, int order, struct mem_cgroup *memcg),
+	TP_PROTO(struct scan_control *sc, struct mem_cgroup *memcg),
 
-	TP_ARGS(gfp_flags, order, memcg)
+	TP_ARGS(sc, memcg)
 );
 
 #ifdef CONFIG_MEMCG
 DEFINE_EVENT(mm_vmscan_direct_reclaim_begin_template, mm_vmscan_memcg_reclaim_begin,
 
-	TP_PROTO(gfp_t gfp_flags, int order, struct mem_cgroup *memcg),
+	TP_PROTO(struct scan_control *sc, struct mem_cgroup *memcg),
 
-	TP_ARGS(gfp_flags, order, memcg)
+	TP_ARGS(sc, memcg)
 );
 #endif /* CONFIG_MEMCG */
 
@@ -551,9 +551,9 @@ TRACE_EVENT(mm_vmscan_lru_shrink_active,
 
 TRACE_EVENT(mm_vmscan_node_reclaim_begin,
 
-	TP_PROTO(int nid, int order, gfp_t gfp_flags),
+	TP_PROTO(int nid, struct scan_control *sc),
 
-	TP_ARGS(nid, order, gfp_flags),
+	TP_ARGS(nid, sc),
 
 	TP_STRUCT__entry(
 		__field(int, nid)
@@ -563,8 +563,8 @@ TRACE_EVENT(mm_vmscan_node_reclaim_begin,
 
 	TP_fast_assign(
 		__entry->nid = nid;
-		__entry->order = order;
-		__entry->gfp_flags = (__force unsigned long)gfp_flags;
+		__entry->order = sc->order;
+		__entry->gfp_flags = (__force unsigned long)sc->gfp_mask;
 	),
 
 	TP_printk("nid=%d order=%d gfp_flags=%s",
diff --git a/mm/vmscan.c b/mm/vmscan.c
index ab118f6b32eb..2979d0d819a8 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -6885,7 +6885,7 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
 		return 1;
 
 	set_task_reclaim_state(current, &sc.reclaim_state);
-	trace_mm_vmscan_direct_reclaim_begin(sc.gfp_mask, order, NULL);
+	trace_mm_vmscan_direct_reclaim_begin(&sc, NULL);
 
 	nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
 
@@ -6926,7 +6926,7 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
 	struct zonelist *zonelist = node_zonelist(numa_node_id(), sc.gfp_mask);
 
 	set_task_reclaim_state(current, &sc.reclaim_state);
-	trace_mm_vmscan_memcg_reclaim_begin(sc.gfp_mask, 0, memcg);
+	trace_mm_vmscan_memcg_reclaim_begin(&sc, memcg);
 	noreclaim_flag = memalloc_noreclaim_save();
 
 	nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
@@ -7882,8 +7882,7 @@ static unsigned long __node_reclaim(struct pglist_data *pgdat,
 	unsigned int noreclaim_flag;
 	unsigned long pflags;
 
-	trace_mm_vmscan_node_reclaim_begin(pgdat->node_id, sc->order,
-					   sc->gfp_mask);
+	trace_mm_vmscan_node_reclaim_begin(pgdat->node_id, sc);
 
 	cond_resched();
 	psi_memstall_enter(&pflags);
-- 
2.34.1

[PATCH RFC v3 5/7] mm/vmscan: pass scan_control to the LRU isolate/shrink tracepoints

[Ridong Chen]

From: Ridong Chen <chenridong@xiaomi.com>

mm_vmscan_lru_isolate, mm_vmscan_lru_shrink_inactive and
mm_vmscan_lru_shrink_active spell out reclaim state (reclaim_idx, order,
priority) as individual arguments, all of which the caller already holds
in struct scan_control. Now that the struct is visible from the trace
header, pass sc directly and pick the fields out in TP_fast_assign.

No functional change. The tracefs event format (TP_STRUCT__entry and
TP_printk) is unchanged, so tracefs-based consumers are unaffected.
BPF programs attached via raw_tp/tp_btf see the new TP_PROTO and need
to be adjusted; tracepoints are not a stable ABI (see
Documentation/bpf/bpf_design_QA.rst).

Assisted-by: LLM
Signed-off-by: Ridong Chen <chenridong@xiaomi.com>
---
 mm/trace_vmscan.h | 31 +++++++++++++++----------------
 mm/vmscan.c       | 14 +++++++-------
 2 files changed, 22 insertions(+), 23 deletions(-)

diff --git a/mm/trace_vmscan.h b/mm/trace_vmscan.h
index 28561fda83b3..aa27cb9524bb 100644
--- a/mm/trace_vmscan.h
+++ b/mm/trace_vmscan.h
@@ -350,15 +350,14 @@ TRACE_EVENT(mm_shrink_slab_end,
 );
 
 TRACE_EVENT(mm_vmscan_lru_isolate,
-	TP_PROTO(int highest_zoneidx,
-		int order,
-		unsigned long nr_requested,
-		unsigned long nr_scanned,
-		unsigned long nr_skipped,
-		unsigned long nr_taken,
-		int lru),
+	TP_PROTO(struct scan_control *sc,
+		 unsigned long nr_requested,
+		 unsigned long nr_scanned,
+		 unsigned long nr_skipped,
+		 unsigned long nr_taken,
+		 int lru),
 
-	TP_ARGS(highest_zoneidx, order, nr_requested, nr_scanned, nr_skipped, nr_taken, lru),
+	TP_ARGS(sc, nr_requested, nr_scanned, nr_skipped, nr_taken, lru),
 
 	TP_STRUCT__entry(
 		__field(int, highest_zoneidx)
@@ -371,8 +370,8 @@ TRACE_EVENT(mm_vmscan_lru_isolate,
 	),
 
 	TP_fast_assign(
-		__entry->highest_zoneidx = highest_zoneidx;
-		__entry->order = order;
+		__entry->highest_zoneidx = sc->reclaim_idx;
+		__entry->order = sc->order;
 		__entry->nr_requested = nr_requested;
 		__entry->nr_scanned = nr_scanned;
 		__entry->nr_skipped = nr_skipped;
@@ -466,9 +465,9 @@ TRACE_EVENT(mm_vmscan_lru_shrink_inactive,
 
 	TP_PROTO(int nid,
 		unsigned long nr_scanned, unsigned long nr_reclaimed,
-		struct reclaim_stat *stat, int priority, int file),
+		struct reclaim_stat *stat, struct scan_control *sc, int file),
 
-	TP_ARGS(nid, nr_scanned, nr_reclaimed, stat, priority, file),
+	TP_ARGS(nid, nr_scanned, nr_reclaimed, stat, sc, file),
 
 	TP_STRUCT__entry(
 		__field(int, nid)
@@ -498,7 +497,7 @@ TRACE_EVENT(mm_vmscan_lru_shrink_inactive,
 		__entry->nr_activate1 = stat->nr_activate[1];
 		__entry->nr_ref_keep = stat->nr_ref_keep;
 		__entry->nr_unmap_fail = stat->nr_unmap_fail;
-		__entry->priority = priority;
+		__entry->priority = sc->priority;
 		__entry->reclaim_flags = trace_reclaim_flags(file);
 	),
 
@@ -517,9 +516,9 @@ TRACE_EVENT(mm_vmscan_lru_shrink_active,
 
 	TP_PROTO(int nid, unsigned long nr_taken,
 		unsigned long nr_active, unsigned long nr_deactivated,
-		unsigned long nr_referenced, int priority, int file),
+		unsigned long nr_referenced, struct scan_control *sc, int file),
 
-	TP_ARGS(nid, nr_taken, nr_active, nr_deactivated, nr_referenced, priority, file),
+	TP_ARGS(nid, nr_taken, nr_active, nr_deactivated, nr_referenced, sc, file),
 
 	TP_STRUCT__entry(
 		__field(int, nid)
@@ -537,7 +536,7 @@ TRACE_EVENT(mm_vmscan_lru_shrink_active,
 		__entry->nr_active = nr_active;
 		__entry->nr_deactivated = nr_deactivated;
 		__entry->nr_referenced = nr_referenced;
-		__entry->priority = priority;
+		__entry->priority = sc->priority;
 		__entry->reclaim_flags = trace_reclaim_flags(file);
 	),
 
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 2979d0d819a8..c25ba910149d 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1764,7 +1764,7 @@ static unsigned long isolate_lru_folios(unsigned long nr_to_scan,
 		}
 	}
 	*nr_scanned = total_scan;
-	trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, nr_to_scan,
+	trace_mm_vmscan_lru_isolate(sc, nr_to_scan,
 				    total_scan, skipped, nr_taken, lru);
 	update_lru_sizes(lruvec, lru, nr_zone_taken);
 	return nr_taken;
@@ -2053,7 +2053,7 @@ static unsigned long shrink_inactive_list(unsigned long nr_to_scan,
 
 	handle_reclaim_writeback(nr_taken, pgdat, sc, &stat);
 	trace_mm_vmscan_lru_shrink_inactive(pgdat->node_id,
-			nr_scanned, nr_reclaimed, &stat, sc->priority, file);
+			nr_scanned, nr_reclaimed, &stat, sc, file);
 	return nr_reclaimed;
 }
 
@@ -2160,7 +2160,7 @@ static void shrink_active_list(unsigned long nr_to_scan,
 		mod_lruvec_state(lruvec, PGROTATE_ANON + file, nr_rotated);
 
 	trace_mm_vmscan_lru_shrink_active(pgdat->node_id, nr_taken, nr_activate,
-			nr_deactivate, nr_rotated, sc->priority, file);
+			nr_deactivate, nr_rotated, sc, file);
 }
 
 static unsigned int reclaim_folio_list(struct list_head *folio_list,
@@ -4850,9 +4850,9 @@ static int scan_folios(unsigned long nr_to_scan, struct lruvec *lruvec,
 	mod_lruvec_state(lruvec, item, isolated);
 	mod_lruvec_state(lruvec, PGREFILL, sorted);
 	mod_lruvec_state(lruvec, PGSCAN_ANON + type, isolated);
-	trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, nr_to_scan,
-				scanned, skipped, isolated,
-				type ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON);
+	trace_mm_vmscan_lru_isolate(sc, nr_to_scan,
+				    scanned, skipped, isolated,
+				    type ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON);
 
 	*isolatedp = isolated;
 	return scanned;
@@ -4991,7 +4991,7 @@ static int evict_folios(unsigned long nr_to_scan, struct lruvec *lruvec,
 	if (isolated)
 		handle_reclaim_writeback(isolated, pgdat, sc, &stat);
 	trace_mm_vmscan_lru_shrink_inactive(pgdat->node_id,
-			type_scanned, reclaimed, &stat, sc->priority,
+			type_scanned, reclaimed, &stat, sc,
 			type ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON);
 
 	list_for_each_entry_safe_reverse(folio, next, &list, lru) {
-- 
2.34.1

[PATCH RFC v3 6/7] mm/vmscan: pass scan_control to mm_vmscan_reclaim_pages

[Ridong Chen]

From: Ridong Chen <chenridong@xiaomi.com>

reclaim_folio_list() passes sc.nr_scanned to mm_vmscan_reclaim_pages as
a bare argument. Pass the enclosing struct scan_control instead and read
nr_scanned out in TP_fast_assign, consistent with the other reclaim
tracepoints. nr_reclaimed stays a separate argument: it is the return
value of shrink_folio_list(), which does not update sc->nr_reclaimed.

No functional change. The tracefs event format (TP_STRUCT__entry and
TP_printk) is unchanged, so tracefs-based consumers are unaffected.
BPF programs attached via raw_tp/tp_btf see the new TP_PROTO and need
to be adjusted; tracepoints are not a stable ABI (see
Documentation/bpf/bpf_design_QA.rst).

Assisted-by: LLM
Signed-off-by: Ridong Chen <chenridong@xiaomi.com>
---
 mm/trace_vmscan.h | 10 +++++-----
 mm/vmscan.c       |  2 +-
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/mm/trace_vmscan.h b/mm/trace_vmscan.h
index aa27cb9524bb..96e41f444924 100644
--- a/mm/trace_vmscan.h
+++ b/mm/trace_vmscan.h
@@ -418,11 +418,11 @@ TRACE_EVENT(mm_vmscan_write_folio,
 
 TRACE_EVENT(mm_vmscan_reclaim_pages,
 
-	TP_PROTO(int nid,
-		unsigned long nr_scanned, unsigned long nr_reclaimed,
-		struct reclaim_stat *stat),
+	TP_PROTO(int nid, struct scan_control *sc,
+		 unsigned long nr_reclaimed,
+		 struct reclaim_stat *stat),
 
-	TP_ARGS(nid, nr_scanned, nr_reclaimed, stat),
+	TP_ARGS(nid, sc, nr_reclaimed, stat),
 
 	TP_STRUCT__entry(
 		__field(int, nid)
@@ -440,7 +440,7 @@ TRACE_EVENT(mm_vmscan_reclaim_pages,
 
 	TP_fast_assign(
 		__entry->nid = nid;
-		__entry->nr_scanned = nr_scanned;
+		__entry->nr_scanned = sc->nr_scanned;
 		__entry->nr_reclaimed = nr_reclaimed;
 		__entry->nr_dirty = stat->nr_dirty;
 		__entry->nr_writeback = stat->nr_writeback;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index c25ba910149d..b3278dbe47bf 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2183,7 +2183,7 @@ static unsigned int reclaim_folio_list(struct list_head *folio_list,
 		list_del(&folio->lru);
 		folio_putback_lru(folio);
 	}
-	trace_mm_vmscan_reclaim_pages(pgdat->node_id, sc.nr_scanned, nr_reclaimed, &stat);
+	trace_mm_vmscan_reclaim_pages(pgdat->node_id, &sc, nr_reclaimed, &stat);
 
 	return nr_reclaimed;
 }
-- 
2.34.1

[PATCH RFC v3 7/7] mm/vmscan: pass scan_control to mm_vmscan_balance_pgdat_end

[Ridong Chen]

From: Ridong Chen <chenridong@xiaomi.com>

balance_pgdat() passes sc.order and sc.nr_reclaimed to
mm_vmscan_balance_pgdat_end as bare arguments. Pass the enclosing
struct scan_control instead and read the fields out in TP_fast_assign,
consistent with the other reclaim tracepoints. highest_zoneidx stays a
separate argument: it is a balance_pgdat() parameter, and
sc.reclaim_idx may differ from it by the time the end event fires.

No functional change. The tracefs event format (TP_STRUCT__entry and
TP_printk) is unchanged, so tracefs-based consumers are unaffected.
BPF programs attached via raw_tp/tp_btf see the new TP_PROTO and need
to be adjusted; tracepoints are not a stable ABI (see
Documentation/bpf/bpf_design_QA.rst).

Assisted-by: LLM
Signed-off-by: Ridong Chen <chenridong@xiaomi.com>
---
 mm/trace_vmscan.h | 9 ++++-----
 mm/vmscan.c       | 3 +--
 2 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/mm/trace_vmscan.h b/mm/trace_vmscan.h
index 96e41f444924..10b3cda1c435 100644
--- a/mm/trace_vmscan.h
+++ b/mm/trace_vmscan.h
@@ -124,10 +124,9 @@ TRACE_EVENT(mm_vmscan_balance_pgdat_begin,
 
 TRACE_EVENT(mm_vmscan_balance_pgdat_end,
 
-	TP_PROTO(int nid, int order, int highest_zoneidx,
-		 unsigned long nr_reclaimed),
+	TP_PROTO(int nid, struct scan_control *sc, int highest_zoneidx),
 
-	TP_ARGS(nid, order, highest_zoneidx, nr_reclaimed),
+	TP_ARGS(nid, sc, highest_zoneidx),
 
 	TP_STRUCT__entry(
 		__field(int, nid)
@@ -138,9 +137,9 @@ TRACE_EVENT(mm_vmscan_balance_pgdat_end,
 
 	TP_fast_assign(
 		__entry->nid = nid;
-		__entry->order = order;
+		__entry->order = sc->order;
 		__entry->highest_zoneidx = highest_zoneidx;
-		__entry->nr_reclaimed = nr_reclaimed;
+		__entry->nr_reclaimed = sc->nr_reclaimed;
 	),
 
 	TP_printk("nid=%d order=%d highest_zoneidx=%-8s nr_reclaimed=%lu",
diff --git a/mm/vmscan.c b/mm/vmscan.c
index b3278dbe47bf..561e14dd490c 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -7403,8 +7403,7 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int highest_zoneidx)
 	psi_memstall_leave(&pflags);
 	set_task_reclaim_state(current, NULL);
 
-	trace_mm_vmscan_balance_pgdat_end(pgdat->node_id, sc.order,
-					  highest_zoneidx, sc.nr_reclaimed);
+	trace_mm_vmscan_balance_pgdat_end(pgdat->node_id, &sc, highest_zoneidx);
 
 	/*
 	 * Return the order kswapd stopped reclaiming at as
-- 
2.34.1