05/06: daemon: Sacrifice builders on OOM.

[guix-commits]

nckx pushed a commit to branch master
in repository guix.

commit d993ed43b2bae8717437aa27d9d33fd223a6411f
Author: Tobias Geerinckx-Rice <me@tobias.gr>
AuthorDate: Sun Nov 19 01:00:00 2023 +0100

    daemon: Sacrifice builders on OOM.
    
    * nix/libstore/build.cc (DerivationGoal::runChild):
    Maximise our OOM score adjustment.
    
    Change-Id: I418c763b499ca16e1ffe3c6033319112b9744f51
---
 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. */