From: Szabolcs Nagy <nsz@port70.net>
To: musl@lists.openwall.com
Subject: Re: New daily reports - debugging alloc.c et al
Date: Sat, 6 Aug 2011 13:15:05 +0200 [thread overview]
Message-ID: <20110806111505.GS29562@port70.net> (raw)
In-Reply-To: <4E3CC5AC.3070404@gmail.com>
* Luka Mar??eti?? <paxcoder@gmail.com> [2011-08-06 06:40:12 +0200]:
> here), but the method of allocation that I've been recommended
> either fails to fulfill its promise, or I'm blind to my own bug.
> Here's a minimal test case:
> http://paste.debian.net/125242/
> A quick explanation: Alloc.c needs to squat most of process' virtual
> memory. I employ a kind of binary search to find the greatest size
> that can be allocated, but then it turns out, mmap and malloc are
> able to continue allocating memory still. Not sure why.
>
it works here as expected
the first loop finds the largest area that can be mmaped
(about 2.9G here)
then the second loop finds extra mmapable smaller regions
(this is slow here as there are about 70000 extra mmappable
pages, it would be better to do it in bigger chunks like:
/*tries to mmap even more now:*/
printf("Number of *additional* bytes mmap'd:\n");
most=0;
for(j=1<<20; j; j/=2) {
printf("%8zu ", j);
for(i=0; mmap(NULL, j*PAGE_SIZE, PROT_NONE, MAP_PRIVATE, fd, 0) != MAP_FAILED; ++i)
printf(".");
most += i*j*PAGE_SIZE;
printf("\n");
}
printf("%zu\n", most);
)
after this the last loop with malloc immediately
fails (there is nothing to mmap anymore, but maybe
if the allocator already has some area reserved
then a few mallocs can succeed)
next prev parent reply other threads:[~2011-08-06 11:15 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-03 22:14 New daily reports Luka Marčetić
2011-08-03 22:46 ` Solar Designer
2011-08-04 10:51 ` Luka Marčetić
2011-08-04 11:54 ` Solar Designer
2011-08-04 12:01 ` Luka Marčetić
2011-08-04 12:12 ` Solar Designer
2011-08-05 0:02 ` New daily reports - started pthread_eintr.c Luka Marčetić
2011-08-05 0:10 ` Solar Designer
2011-08-06 4:40 ` New daily reports - debugging alloc.c et al Luka Marčetić
2011-08-06 11:15 ` Szabolcs Nagy [this message]
2011-08-06 11:50 ` Szabolcs Nagy
2011-08-06 14:34 ` Szabolcs Nagy
2011-08-06 15:38 ` Szabolcs Nagy
2011-08-07 2:41 ` New daily reports - debugging alloc.c still Luka Marčetić
2011-08-07 2:50 ` Solar Designer
2011-08-07 7:32 ` Rich Felker
2011-08-07 22:25 ` Luka Marčetić
2011-08-09 3:02 ` New daily reports - buf.c Luka Marčetić
2011-08-10 1:34 ` New daily reports - nothing Luka Marčetić
2011-08-10 1:38 ` Rich Felker
2011-08-10 11:47 ` Luka Marčetić
2011-08-10 2:02 ` Solar Designer
2011-08-10 11:23 ` Luka Marčetić
2011-08-10 11:56 ` Solar Designer
2011-08-10 12:13 ` Luka Marčetić
2011-08-10 2:07 ` Solar Designer
2011-08-10 2:12 ` Rich Felker
2011-08-10 4:59 ` Rich Felker
2011-08-10 12:09 ` Luka Marčetić
2011-08-10 12:44 ` Luka Marčetić
2011-08-10 14:25 ` Rich Felker
2011-08-10 17:21 ` Luka Marčetić
2011-08-10 17:33 ` Rich Felker
2011-08-10 18:23 ` Luka Marčetić
2011-08-10 18:21 ` Rich Felker
2011-08-10 18:34 ` Luka Marčetić
2011-08-10 18:33 ` Rich Felker
2011-08-14 20:00 ` Rich Felker
2011-08-15 14:14 ` Luka Marčetić
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