[LTP] [PATCH v2] hugepages: make compact_memory setup optional

[LTP] [PATCH v2] hugepages: make compact_memory setup optional

[Andrea Cervesato]

From: Andrea Cervesato <andrea.cervesato@suse.com>

Writing 1 to /proc/sys/vm/compact_memory only triggers proactive
memory compaction. It's a best-effort hint that makes a hugepage
reservation more likely to succeed by defragmenting memory
beforehand, but the reservation itself does not depend on it.

The kernel can (and often will) still satisfy the request without
any explicit compaction step. So treating a missing compact_memory
(i.e. CONFIG_COMPACTION=n) as a hard TCONF is too strict: it skips
tests that could otherwise run perfectly fine.

Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>
Suggested-by: Li Wang <li.wang@linux.dev>
---
The issue was raised by https://github.com/linux-test-project/ltp/pull/1335
that is trying to solve a problem with cachestat03.
---
Changes in v2:
- change the patch with Li suggestion and description
- Link to v1: https://lore.kernel.org/20260717-fix_tst_test_hugepages-v1-1-a63bf2ccdd17@suse.com
---
 lib/tst_hugepage.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/tst_hugepage.c b/lib/tst_hugepage.c
index 40ecfa162a236a8674628f8ffe7a8fd2ccd52712..d5e1650d2ae65eaede662af9a2435fea2d3ef61f 100644
--- a/lib/tst_hugepage.c
+++ b/lib/tst_hugepage.c
@@ -47,7 +47,7 @@ unsigned long tst_reserve_hugepages(struct tst_hugepage *hp)
 	}
 
 	SAFE_FILE_PRINTF(PATH_VM_DROP_CACHES, "3");
-	SAFE_FILE_PRINTF(PATH_VM_COMPACT_MEMORY, "1");
+	FILE_PRINTF(PATH_VM_COMPACT_MEMORY, "1");
 	if (hp->policy == TST_NEEDS) {
 		tst_hugepages += SAFE_READ_MEMINFO("HugePages_Total:");
 		goto set_hugepages;

---
base-commit: b8eb2e087e13eb85c9a77baa3fb3533eedd55098
change-id: 20260717-fix_tst_test_hugepages-fb3c88e9716c

Best regards,
-- 
Andrea Cervesato <andrea.cervesato@suse.com>


-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] [PATCH v2] hugepages: make compact_memory setup optional

[Li Wang]

Reviewed-by: Li Wang <li.wang@linux.dev>

-- 
Regards,
Li Wang

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] [PATCH v2] hugepages: make compact_memory setup optional

[Cyril Hrubis]

Hi!
Reviewed-by: Cyril Hrubis <chrubis@suse.cz>

-- 
Cyril Hrubis
chrubis@suse.cz

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] [PATCH v2] hugepages: make compact_memory setup optional

[Andrea Cervesato via ltp]

Merged, Thanks!

--
Andrea Cervesato
SUSE QE Automation Engineer Linux
andrea.cervesato@suse.com

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp