[no subject]

[Ludovic Courtès]

branch: master
commit 161d6abef81784a1adb460d5bba40e03b627ceb2
Author: Ludovic Courtès <address@hidden>
Date:   Tue Jan 30 23:58:47 2018 +0100

    base: Work around Fibers I/O scheduling bug.
    
    Works around <https://github.com/wingo/fibers/issues/19>.
    
    The effect in practice would be that we'd usually not reach the
    'close-pipe' call in 'evaluate', leaving zombie processes behind us,
    never executing the continuation, and additionally spinning fast on a
    sequence of epoll_wait/epoll_ctl calls.
    
    * src/cuirass/base.scm <top level>: Monkey-patch (fibers internal).
---
 src/cuirass/base.scm | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/cuirass/base.scm b/src/cuirass/base.scm
index 510b155..aacfb92 100644
--- a/src/cuirass/base.scm
+++ b/src/cuirass/base.scm
@@ -204,6 +204,16 @@ fibers."
     ((? string? data)
      (call-with-input-string data read))))
 
+(match (resolve-module '(fibers internal) #t #f #:ensure #f)
+  (#f #t)                                         ;Fibers > 1.0.0
+  ((? module? internal)                           ;Fibers <= 1.0.0
+   ;; Work around <https://github.com/wingo/fibers/issues/19>.
+   ;; This monkey-patching aims to replace EPOLLERR occurrences in
+   ;; 'schedule-fibers-for-fd' with EPOLLERR | EPOLLHUP.
+   (module-define! internal 'EPOLLERR
+                   (logior (@ (fibers epoll) EPOLLERR)
+                           (@ (fibers epoll) EPOLLHUP)))))
+
 (define (evaluate store db spec)
   "Evaluate and build package derivations.  Return a list of jobs."
   (let* ((port (non-blocking-port