[Chicken-janitors] Re: [Chicken-bugs] #367: optionally use mmap(2) to allocate the heap for safer usage of tospace-locking

[Chicken Scheme]

#367: optionally use mmap(2) to allocate the heap for safer usage of tospace-
locking
-----------------------------+----------------------------------------------
  Reporter:  felix           |       Owner:     
      Type:  enhancement     |      Status:  new
  Priority:  minor           |   Milestone:     
 Component:  core libraries  |     Version:  2.7
Resolution:                  |    Keywords:     
-----------------------------+----------------------------------------------
Comment (by Ivan Shmakov <address@hidden>):

 Actually, I see no point in using mmap () just optionally iff
         the tospace-locking feature was requested, provided that such a
         feature is implemented on top of mprotect ().

         In order to familiarise myself with the Chicken internals, and
         to have some fun this evening as well, I've written the attached
         patch.

         I've successfully built Chicken with Chicken compiled with this
         patch.

 {{{
 chicken $ mkdir +build-2 && cd +build-2/
 +build-2 $ LC_ALL=C nohup time make -f ../Makefile srcdir=.. \
                PREFIX=/nowhere/just/a/test ARCH=x86 PLATFORM=linux \
                USE_HOST_PCRE=yes LOCKTOSPACE=yes -j 4 \
                CHICKEN=../+build-1/chicken
 ...
 +build-2 $ tail -n3 nohup.out
 make[1]: Leaving directory `/.../+build-2'
 414.38user 185.30system 2:33.85elapsed 389%CPU (0avgtext+0avgdata
 0maxresident)k
 0inputs+0outputs (0major+3712308minor)pagefaults 0swaps
 +build-2 $ ./csi

 CHICKEN
 Version 3.0.0rc1 - linux-unix-gnu-x86   [ manyargs dload ptables applyhook
 lockts hostpcre ]
 (c)2000-2007 Felix L. Winkelmann        compiled 2008-01-18 on [...]
 (Linux)

 #;1> ,q
 +build-2 $
 }}}

         As a possible way to improve this further, I'd propose using a
         struct like the following for `heapspace's:

 {{{
 struct {
   C_byte *ptr;
 #ifdef C_LOCK_TOSPACE
   size_t size;
 #endif
 } heapspace1, heapspace2;
 }}}

         since `size' is required for munmap ().

-- 
Ticket URL: <http://trac.callcc.org/ticket/367#comment:1>
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