pthread_create fails on a device with 16MB RAM

[Alexander Gordeev]

В Fri, 28 Jan 2011 09:31:37 +0000
Carl Shaw <shaw.carl at gmail.com> пишет:

> On 28/01/11 00:39, Alexander Gordeev wrote:
> > Hi!
> > 
> > I have a problem with pthread_create on a device with only 16MB RAM.
> > strace shows this:
> > 
> > old_mmap(NULL, 8388608, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = -1 ENOMEM (Cannot allocate memory)
> > 
> > instead of (what I obtained on another device with 32MB RAM):
> > 
> > old_mmap(NULL, 8388608, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, 2143089904, 0x2b985918) = 0x2bc6b000
> > mprotect(0x2bc6b000, 4096, PROT_NONE)   = 0
> > clone(child_stack=0x2c46a3b0, flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS|CLONE_PARENT_SETTID|CLONE_CHILD_CLEARTID, parent_tidptr=0x2c46a6f8, tls=0x2c471960, child_tidptr=0) = 1394
> > 
> > which is quite reasonable because 8388608 is greater than half the
> > amount of available physical memory which AFAIK is a limit for memory
> > allocations normally. When I did
> > 
> > echo 1 > /proc/sys/vm/overcommit_memory
> > 
> > everything worked like a charm (because this limit was disabled).
> > 
> > How can I tune uClibc to not request so much memory on pthread_create?
> 
> This occurs because the default maximum stack size is usually 8MB (check
> using ulimit -s or -a at a shell prompt).
> 
> You have a number of options to change this:
> 
> 1.  Change the default maximum stack size.  This can be done in a shell
> by using ulimit -s or by using the setrlimit() C lib function call with
> RLIMIT_STACK option.  You can set an explicit value (16 kiB min) or if
> you set it to RLIM_INFINITY then a architecture-dependent default size
> will be used (in NPTL this is defined in sysdeps/<arch>/pthreaddef.h in
> ARCH_STACK_DEFAULT_SIZE in linuxthreads the header file is pt-machine.h)
> 2.  Allocate your own stack memory, insert into to a thread attribute
> structure using pthread_attr_setstack() and use that when creating the
> thread with pthread_create()
> 3.  Patch the C library to use a more appropriate default rather than
> calling getrlimit(RLIMIT_STACK)!

It works, thank you very much!

-- 
  Alexander
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