build: propagate USE_JEMALLOC (#422)

* build: propagate USE_JEMALLOC

see #418 (comment)

deps/build.jl

@@ -73,6 +73,7 @@ const CC  = get(ENV, "CC", nothing)
 const CXX = get(ENV, "CXX", nothing)
 const ADD_CFLAGS  = get(ENV, "ADD_CFLAGS", nothing)
 const ADD_LDFLAGS = get(ENV, "ADD_LDFLAGS", nothing)
+const USE_JEMALLOC = get(ENV, "USE_JEMALLOC", nothing)  # "0" or "1"
 
 function get_cpucore()
     if haskey(ENV, "TRAVIS")  # on travis-ci
@@ -238,6 +239,9 @@ if !libmxnet_detected
           if ADD_LDFLAGS != nothing
             `sed -i -s "s@ADD_LDFLAGS =\(.*\)@ADD_LDFLAGS =\1 $ADD_LDFLAGS@" config.mk`
           end
+          if USE_JEMALLOC != nothing
+            `sed -i -s "s@USE_JEMALLOC =\(.*\)@USE_JEMALLOC = $USE_JEMALLOC@" config.mk`
+          end
 
           if USE_JULIA_BLAS
             `make -j$(get_cpucore()) USE_BLAS=$blas_name $MSHADOW_LDFLAGS`

docs/src/user-guide/install.md

@@ -37,6 +37,15 @@ There are several environment variables that change this behaviour.
   if you need to point non-standard include directory, please set it as
   `ENV["ADD_CFLAGS"] = "-I'/path/to/include/dir'"`.
 - `ADD_LDFLAGS`: Additional linker flags.
+- `USE_JEMALLOC`: Default is enabled if jemalloc available.
+  If you ran into segfault cause by jemalloc,
+  Please try to disable it.
+
+  ```julia
+  # first remove whole libmxnet source: Pkg.dir("MXNet", "deps", "src")
+  ENV["USE_JEMALLOC"] = "0"
+  Pkg.build("MXNet")
+  ```
 
 The libmxnet source is downloaded to `Pkg.dir("MXNet", "deps", "src", "mxnet")`.
 The automatic build is using default configurations, with OpenCV disabled.