mmap(2)-like allocation of buffer text on MS-Windows

mmap(2)-like allocation of buffer text on MS-Windows

[Eli Zaretskii]

Starting with trunk revision 117168, the MS-Windows build uses mmap(2)
emulation code, written by Fabrice Popineau, for allocating buffer
text.  This allows to stop using gmalloc.c and ralloc.c on this
platform, and thus get rid of the nasty problems with buffer text
relocation when large chunks of memory are allocated.  (There are
still a few other platforms that use ralloc.c, though.)

As a nice side-effect (due to changes in how dumped Lisp data is now
recorded on MS-Windows), the produced binary can now be stripped, so
that "make install-strip" should work.

I'd like to take this opportunity to thank Fabrice for his efforts,
and his endurance and perseverance during the long time this project
required.  Special thanks to Juanma for helping test the first
versions of the code.

Enjoy.

Re: mmap(2)-like allocation of buffer text on MS-Windows

[Fabrice Popineau]

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And many thanks to Eli for his (as always) valuable comments and help.

Fabrice

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Re: mmap(2)-like allocation of buffer text on MS-Windows

[Stefan Monnier]

> Starting with trunk revision 117168, the MS-Windows build uses mmap(2)
> emulation code, written by Fabrice Popineau, for allocating buffer
> text.  This allows to stop using gmalloc.c and ralloc.c on this
> platform, and thus get rid of the nasty problems with buffer text
> relocation when large chunks of memory are allocated.

Yay!  Thanks Fabrice et.al!

> (There are still a few other platforms that use ralloc.c, though.)

Which ones would that be?


        Stefan

Re: mmap(2)-like allocation of buffer text on MS-Windows

[Paul Eggert]

On 05/27/2014 12:51 PM, Stefan Monnier wrote:
>> (There are still a few other platforms that use ralloc.c, though.)
> Which ones would that be?

If I'm reading the latest configure.ac correctly, no platform uses 
ralloc.c in the trunk, and we can remove ralloc.c.

Re: mmap(2)-like allocation of buffer text on MS-Windows

[Eli Zaretskii]

> Date: Tue, 27 May 2014 14:02:25 -0700
> From: Paul Eggert <eggert@cs.ucla.edu>
> Cc: emacs-devel@gnu.org
> 
> On 05/27/2014 12:51 PM, Stefan Monnier wrote:
> >> (There are still a few other platforms that use ralloc.c, though.)
> > Which ones would that be?
> 
> If I'm reading the latest configure.ac correctly, no platform uses 
> ralloc.c in the trunk, and we can remove ralloc.c.

I thought the *BSD systems did, don't they?

Anyway, the MS-DOS build certainly does, so ralloc.c shouldn't be
removed yet.

Re: mmap(2)-like allocation of buffer text on MS-Windows

[Paul Eggert]

Eli Zaretskii wrote:
>> If I'm reading the latest configure.ac correctly, no platform uses
>> >ralloc.c in the trunk, and we can remove ralloc.c.
> I thought the *BSD systems did, don't they?

Sorry, I was too hasty in reading configure.ac.  On rereading it, it 
appears that ralloc.c is used on DragonFly, NetBSD, OpenBSD, HP-UX, AIX, 
Solaris 9-and-earlier, and Unixware.  ralloc.c is not used on FreeBSD, 
though, as that uses mmap for buffers.

Re: mmap(2)-like allocation of buffer text on MS-Windows

[Eli Zaretskii]

> Date: Tue, 27 May 2014 20:39:01 -0700
> From: Paul Eggert <eggert@cs.ucla.edu>
> CC: emacs-devel@gnu.org
> 
> ralloc.c is not used on FreeBSD, though, as that uses mmap for
> buffers.

That figures: Gerd Moellmann, who implemented the mmap allocation,
used FreeBSD at the time, AFAIR.

Re: mmap(2)-like allocation of buffer text on MS-Windows

[Stefan Monnier]

> That figures: Gerd Moellmann, who implemented the mmap allocation,
> used FreeBSD at the time, AFAIR.

Any good reason not to use mmap on the other BSDs?


        Stefan

Re: mmap(2)-like allocation of buffer text on MS-Windows

[Eli Zaretskii]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: Paul Eggert <eggert@cs.ucla.edu>,  emacs-devel@gnu.org
> Date: Wed, 28 May 2014 13:41:21 -0400
> 
> > That figures: Gerd Moellmann, who implemented the mmap allocation,
> > used FreeBSD at the time, AFAIR.
> 
> Any good reason not to use mmap on the other BSDs?

No clue here.  I'm not familiar with these systems, I just remembered
that during some past pretest (23.4, perhaps?) some *BSD user reported
a crash that involved ralloc.c.