See upstream commit:
commit 5ecd9d403ad081ed2de7b118c1e96124d4e0ba6c
Author: David Rientjes <rient...@google.com>
Date: Thu Apr 5 16:25:16 2018 -0700
mm, page_alloc: wakeup kcompactd even if kswapd cannot free more memory
Kswapd will not wakeup if per-zone watermarks are not failing or if too
many previous attempts at background reclaim have failed.
This can be true if there is a lot of free memory available. For high-
order allocations, kswapd is responsible for waking up kcompactd for
background compaction. If the zone is not below its watermarks or
reclaim has recently failed (lots of free memory, nothing left to
reclaim), kcompactd does not get woken up.
When __GFP_DIRECT_RECLAIM is not allowed, allow kcompactd to still be
woken up even if kswapd will not reclaim. This allows high-order
allocations, such as thp, to still trigger background compaction even
when the zone has an abundance of free memory.
Signed-off-by: Michael Jeanson <mjean...@efficios.com>
---
instrumentation/events/lttng-module/mm_vmscan.h | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/instrumentation/events/lttng-module/mm_vmscan.h
b/instrumentation/events/lttng-module/mm_vmscan.h
index a69b42f..9661c9d 100644
--- a/instrumentation/events/lttng-module/mm_vmscan.h
+++ b/instrumentation/events/lttng-module/mm_vmscan.h
@@ -84,6 +84,21 @@ LTTNG_TRACEPOINT_EVENT(mm_vmscan_kswapd_wake,
#endif
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,17,0))
+LTTNG_TRACEPOINT_EVENT(mm_vmscan_wakeup_kswapd,
+
+ TP_PROTO(int nid, int zid, int order, gfp_t gfp_flags),
+
+ TP_ARGS(nid, zid, order, gfp_flags),
+
+ TP_FIELDS(
+ ctf_integer(int, nid, nid)
+ ctf_integer(int, zid, zid)
+ ctf_integer(int, order, order)
+ ctf_integer(gfp_t, gfp_flags, gfp_flags)
+ )
+)
+#else
LTTNG_TRACEPOINT_EVENT(mm_vmscan_wakeup_kswapd,
TP_PROTO(int nid, int zid, int order),
@@ -96,6 +111,7 @@ LTTNG_TRACEPOINT_EVENT(mm_vmscan_wakeup_kswapd,
ctf_integer(int, order, order)
)
)
+#endif
#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,8,0))
--
2.7.4
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