| From f4a6415f8d5fa447868d1fdc7119e0a328966379 Mon Sep 17 00:00:00 2001 |
| From: Kienan Stewart <kstewart@efficios.com> |
| Date: Mon, 25 Mar 2024 10:30:32 -0400 |
| Subject: [PATCH 3/4] Fix: mm_compaction_migratepages changed in linux 6.9-rc1 |
| |
| See upstream commit: |
| |
| commit ab755bf4249b992fc2140d615ab0a686d50765b4 |
| Author: Baolin Wang <baolin.wang@linux.alibaba.com> |
| Date: Tue Feb 20 14:16:31 2024 +0800 |
| |
| mm: compaction: update the cc->nr_migratepages when allocating or freeing the freepages |
| |
| Currently we will use 'cc->nr_freepages >= cc->nr_migratepages' comparison |
| to ensure that enough freepages are isolated in isolate_freepages(), |
| however it just decreases the cc->nr_freepages without updating |
| cc->nr_migratepages in compaction_alloc(), which will waste more CPU |
| cycles and cause too many freepages to be isolated. |
| |
| So we should also update the cc->nr_migratepages when allocating or |
| freeing the freepages to avoid isolating excess freepages. And I can see |
| fewer free pages are scanned and isolated when running thpcompact on my |
| Arm64 server: |
| |
| k6.7 k6.7_patched |
| Ops Compaction pages isolated 120692036.00 118160797.00 |
| Ops Compaction migrate scanned 131210329.00 154093268.00 |
| Ops Compaction free scanned 1090587971.00 1080632536.00 |
| Ops Compact scan efficiency 12.03 14.26 |
| |
| Moreover, I did not see an obvious latency improvements, this is likely |
| because isolating freepages is not the bottleneck in the thpcompact test |
| case. |
| |
| k6.7 k6.7_patched |
| Amean fault-both-1 1089.76 ( 0.00%) 1080.16 * 0.88%* |
| Amean fault-both-3 1616.48 ( 0.00%) 1636.65 * -1.25%* |
| Amean fault-both-5 2266.66 ( 0.00%) 2219.20 * 2.09%* |
| Amean fault-both-7 2909.84 ( 0.00%) 2801.90 * 3.71%* |
| Amean fault-both-12 4861.26 ( 0.00%) 4733.25 * 2.63%* |
| Amean fault-both-18 7351.11 ( 0.00%) 6950.51 * 5.45%* |
| Amean fault-both-24 9059.30 ( 0.00%) 9159.99 * -1.11%* |
| Amean fault-both-30 10685.68 ( 0.00%) 11399.02 * -6.68%* |
| |
| Upstream-Status: Backport [175fe77c Fix: mm_compaction_migratepages changed in linux 6.9-rc1] |
| |
| Change-Id: I103a43fd1b549360b3fc978fd409b7c17ef3e192 |
| Signed-off-by: Kienan Stewart <kstewart@efficios.com> |
| Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| --- |
| include/instrumentation/events/compaction.h | 17 ++++++++++++++++- |
| 1 file changed, 16 insertions(+), 1 deletion(-) |
| |
| Index: lttng-modules-2.13.12/include/instrumentation/events/compaction.h |
| =================================================================== |
| --- lttng-modules-2.13.12.orig/include/instrumentation/events/compaction.h |
| +++ lttng-modules-2.13.12/include/instrumentation/events/compaction.h |
| @@ -97,7 +97,22 @@ LTTNG_TRACEPOINT_EVENT_INSTANCE_MAP(comp |
| |
| #endif /* #else #if LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,0,0) */ |
| |
| -#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,18,0) || \ |
| +#if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(6,9,0)) |
| +LTTNG_TRACEPOINT_EVENT_MAP(mm_compaction_migratepages, |
| + |
| + compaction_migratepages, |
| + |
| + TP_PROTO(unsigned int nr_migratepages, |
| + unsigned int nr_succeeded), |
| + |
| + TP_ARGS(nr_migratepages, nr_succeeded), |
| + |
| + TP_FIELDS( |
| + ctf_integer(unsigned long, nr_migrated, nr_succeeded) |
| + ctf_integer(unsigned long, nr_failed, nr_migratepages - nr_succeeded) |
| + ) |
| +) |
| +#elif (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,18,0) || \ |
| LTTNG_RHEL_KERNEL_RANGE(5,14,0,163,0,0, 5,15,0,0,0,0)) |
| LTTNG_TRACEPOINT_EVENT_MAP(mm_compaction_migratepages, |
| |