digitalmars.D.bugs - [Issue 7251] New: GC not working
- d-bugmail puremagic.com (50/50) Jan 08 2012 http://d.puremagic.com/issues/show_bug.cgi?id=7251
- d-bugmail puremagic.com (13/13) Jan 09 2012 http://d.puremagic.com/issues/show_bug.cgi?id=7251
- d-bugmail puremagic.com (11/11) Feb 29 2012 http://d.puremagic.com/issues/show_bug.cgi?id=7251
- d-bugmail puremagic.com (13/14) Mar 01 2012 http://d.puremagic.com/issues/show_bug.cgi?id=7251
- d-bugmail puremagic.com (14/18) Mar 01 2012 http://d.puremagic.com/issues/show_bug.cgi?id=7251
- d-bugmail puremagic.com (14/26) Mar 01 2012 http://d.puremagic.com/issues/show_bug.cgi?id=7251
- d-bugmail puremagic.com (15/26) Mar 01 2012 http://d.puremagic.com/issues/show_bug.cgi?id=7251
- d-bugmail puremagic.com (19/37) Mar 04 2012 http://d.puremagic.com/issues/show_bug.cgi?id=7251
- d-bugmail puremagic.com (14/14) May 30 2013 http://d.puremagic.com/issues/show_bug.cgi?id=7251
http://d.puremagic.com/issues/show_bug.cgi?id=7251
Summary: GC not working
Product: D
Version: D2
Platform: x86
OS/Version: Windows
Status: NEW
Severity: regression
Priority: P2
Component: druntime
AssignedTo: nobody puremagic.com
ReportedBy: wfunction hotmail.com
On DMD 2.057, the code:
import core.memory, std.stdio;
extern(Windows) int GlobalMemoryStatusEx(ref MEMORYSTATUSEX lpBuffer);
struct MEMORYSTATUSEX
{
uint Length, MemoryLoad;
ulong TotalPhys, AvailPhys, TotalPageFile, AvailPageFile;
ulong TotalVirtual, AvailVirtual, AvailExtendedVirtual;
}
void testA(size_t count)
{
size_t[] a;
foreach (i; 0 .. count)
a ~= i;
}
void main()
{
MEMORYSTATUSEX ms;
ms.Length = ms.sizeof;
foreach (i; 0 .. 32)
{
testA(16 << 20);
GlobalMemoryStatusEx(ms);
stderr.writefln("AvailPhys: %s MiB", ms.AvailPhys >>> 20);
}
}
Gives output:
AvailPhys: 3711 MiB
AvailPhys: 3365 MiB
AvailPhys: 3061 MiB
AvailPhys: 2747 MiB
AvailPhys: 2458 MiB
core.exception.OutOfMemoryError
Obviously, the GC is non-functional...
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Jan 08 2012
d-bugmail puremagic.com
http://d.puremagic.com/issues/show_bug.cgi?id=7251
David Simcha <dsimcha yahoo.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
CC| |dsimcha yahoo.com
Resolution| |INVALID
This looks like false pointers. testA allocates 48 MB for its largest array on
each run. We really need precise heap scanning.
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Jan 09 2012
http://d.puremagic.com/issues/show_bug.cgi?id=7251
wfunction hotmail.com changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |REOPENED
Resolution|INVALID |
Just wondering, why was this marked as "Resolved, Invalid" with no comment?
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Feb 29 2012
http://d.puremagic.com/issues/show_bug.cgi?id=7251
Don <clugdbug yahoo.com.au> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|REOPENED |RESOLVED
CC| |clugdbug yahoo.com.au
Resolution| |INVALID
Just wondering, why was this marked as "Resolved, Invalid" with no comment?
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Mar 01 2012
http://d.puremagic.com/issues/show_bug.cgi?id=7251
wfunction hotmail.com changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|INVALID |REMIND
Just wondering, why was this marked as "Resolved, Invalid" with no comment?
Wait what?
"This looks like false pointers [...] We really need precise heap scanning."
Doesn't that mean this needs to be fixed? Or is one of us misunderstanding the
meaning of the above?
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Mar 01 2012
http://d.puremagic.com/issues/show_bug.cgi?id=7251No, it's inevitable that a mark-and-sweep GC on a 32 bit system won't work if large numbers of false pointers are present. And this code: foreach (i; 0 .. count) a ~= i; is flooding the system with false pointers. You marked this as regression, is there any previous compiler where this worked? (reopen if it there is). -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------Wait what? "This looks like false pointers [...] We really need precise heap scanning." Doesn't that mean this needs to be fixed? Or is one of us misunderstanding the meaning of the above?Just wondering, why was this marked as "Resolved, Invalid" with no comment?
Mar 01 2012
http://d.puremagic.com/issues/show_bug.cgi?id=7251No, it's inevitable that a mark-and-sweep GC on a 32 bit system won't work if large numbers of false pointers are present. And this code: foreach (i; 0 .. count) a ~= i; is flooding the system with false pointers.I think you might have misunderstood the problem, like I originally did. I am ********** NOT *********** filling the system with false pointers. See David Simcha's comment in response to mine: http://stackoverflow.com/a/8796226/541686 It's inherently defective -- I'm merely _allocating_ a lot of memory, that's all. The rest is a problem with the GC's algorithm. (Unless you expect that no one will allocate one 20-MB chunk of RAM?)You marked this as regression, is there any previous compiler where this worked? (reopen if it there is).I marked it as "remind", since I'm sorta reminding about this bug... if that's not the implied meaning then my bad, but this still needs to be fixed. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Mar 01 2012
http://d.puremagic.com/issues/show_bug.cgi?id=7251
Rob Jacques <sandford jhu.edu> changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P2 |P4
CC| |sandford jhu.edu
Platform|x86 |All
OS/Version|Windows |All
Severity|regression |minor
No, it's inevitable that a mark-and-sweep GC on a 32 bit system won't work if
large numbers of false pointers are present. And this code:
foreach (i; 0 .. count)
a ~= i;
is flooding the system with false pointers.
I think you might have misunderstood the problem, like I originally did.
I am ********** NOT *********** filling the system with false pointers.
See David Simcha's comment in response to mine:
http://stackoverflow.com/a/8796226/541686
It's inherently defective -- I'm merely _allocating_ a lot of memory, that's
all. The rest is a problem with the GC's algorithm.
(Unless you expect that no one will allocate one 20-MB chunk of RAM?)
The static data segment and the stack generate _always_ contain false pointers.
So even if you're not generating them yourself much, they do exist and things
will get stuck.
Also, direct use of ~= is discouraged; appender is recommended instead and
there patch for appender that solves this issue.
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Mar 04 2012
http://d.puremagic.com/issues/show_bug.cgi?id=7251
Leandro Lucarella <leandro.lucarella sociomantic.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |leandro.lucarella sociomant
| |ic.com
Resolution|REMIND |DUPLICATE
2013-05-30 04:54:25 PDT ---
fixed, this one should be fixed too.
*** This issue has been marked as a duplicate of issue 3463 ***
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May 30 2013