Re: Copy data from kernel to user space memory

From: Niels Heinen (niels.heinen_at_gmail.com)
Date: 09/23/04

  • Next message: Phillip Crumpler: "Error 1802: IBM T41 doesn't like other network cards" 
    Date: Thu, 23 Sep 2004 12:52:32 +0200
To: Andrey Simonenko <simon@comsys.ntu-kpi.kiev.ua>

    >
    > I'm not sure that you get some performance with this method, usually
    > an application allocates memory, makes syscall and tells how many bytes
    > the kernel (the module) can store in this memory. But I don't see
    > the complete picture, so may be you can't use this standard approach.
    >

    Thats the way I have implemented it now. But because the application
    (test.c ;p ) doesn't know the packet size its currently using too
    large memory buffers.

    Thanks for the info, I'll have a look at those function !

    Niels
    _______________________________________________
    freebsd-hackers@freebsd.org mailing list
    http://lists.freebsd.org/mailman/listinfo/freebsd-hackers
    To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org"

  • Next message: Phillip Crumpler: "Error 1802: IBM T41 doesn't like other network cards"

    Relevant Pages

    • Re: Exact mechanics of a system call
      ... want to do a syscall interface, ... That depends on the ABI design which would specify what instructions ... to be stored into virtual memory that has no associated real memory, ... OSes use some appropriate trapping CPU instruction on ...
      (comp.os.linux.development.system)
    • Re: Migrate pages from a ccNUMA node to another
      ... relatively stable memory working sets. ... > on the childs node for the child and parents node for the parent. ... we have beaten on the scheduler quite a bit and the "allocate ... > syscall you seem to be proposing, would be an addition to the ...
      (Linux-Kernel)
    • Re: user malloc from kernel
      ... >> which attempt to allocate memory after making the syscall in question? ... > Couldn't the user library interface to this new system call just ... > it until the kernel is done with it. ...
      (freebsd-hackers)
    • [PATCH v2] execve: must clear current->clear_child_tid
      ... clonesyscall has special support for TID of created threads. ... One is to set an integer into user memory with the ... The integer location is a user provided pointer, ... chances are high that we might corrupt user ...
      (Linux-Kernel)
    • Re: Large array in KVM
      ... I'm working on a kernel module that needs to maintain a large ... Could using a memory-mapped file help? ... a process that maps a large file into memory, ... which means a dynamically-allocated syscall via ...
      (freebsd-hackers)