debugging jemalloc

Author: jdetter

.github/workflows/ci.yml

@@ -923,3 +923,11 @@ jobs:
           export CARGO_BUILD_JOBS=1
           export RUST_BACKTRACE=full
           nix flake check -L --show-trace --print-build-logs
+      - name: Dump jemalloc configure log (on failure)
+        if: ${{ failure() }}
+        shell: bash
+        run: |
+          set -euxo pipefail
+          # Find any jemalloc config.log produced in the workspace build dir
+          find /build/source -path '*tikv-jemalloc-sys*' -name config.log -print -exec tail -n 300 {} \; || true
+