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

[Elf]

reason for using mmap optionally is that we're using it in a way that goes
against posix, iirc.

-elf

On Fri, 18 Jan 2008, Chicken Scheme wrote:

> #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 ().