Subject: [PATCH v3] daemon: Sacrifice builders on OOM.

From: Tobias Geerinckx-Rice <[email-masked]>
Date: Sun, 3 Dec 2023 01:00:01 +0100

* nix/libstore/build.cc (DerivationGoal::runChild):
Maximise our OOM score adjustment.

Change-Id: I418c763b499ca16e1ffe3c6033319112b9744f51
---

v3: In my defens, I'm on a fone.

 nix/libstore/build.cc | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/nix/libstore/build.cc b/nix/libstore/build.cc
index e8259aa4e8..54555b92d7 100644
--- a/nix/libstore/build.cc
+++ b/nix/libstore/build.cc
@@ -2154,6 +2154,12 @@ void DerivationGoal::runChild()
            determinism. */
         int cur = personality(0xffffffff);
         if (cur != -1) personality(cur | ADDR_NO_RANDOMIZE);
+
+	/* Ask the kernel to eagerly kill us & our children if it runs out of
+	   memory, regardless of blame, to preserve ‘real’ user data & state. */
+	try {
+	    writeFile("/proc/self/oom_score_adj", "1000"); // 100%
+	} catch (...) { ignoreException(); }
 #endif
 
         /* Fill in the environment. */

base-commit: e796c68025aca372ff8e16eb0c235155af92f743
-- 
2.41.0