Messages in this thread | | | Date | Thu, 29 Sep 2005 16:50:25 -0700 (PDT) | From | Wilson Li <> | Subject | Re: Slow loading big kernel module in 2.6 on PPC platform |
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>--- "linux-os (Dick Johnson)" <linux-os@analogic.com> wrote: > > On Wed, 28 Sep 2005, Wilson Li wrote: > > I have a module I am currently working on. It has some assembly > stuff linked with it, so it was easy to modify. In the assembly > I allocated 16 megabytes of static storage (using the .space > keyword), > first in the .data section, then in .rodata, then in .text. The > .text section is where code exists. In no case did the module take > more than 1/4 second to load. In all cases the size shown by > `lsmod` > reflected the enormous size of the module. > > Now, that's static storage. If your code uses kmalloc() and > friends to allocate a lot of storage when it is being loaded, > then that's a different story. FYI, when you see a kernel message > on the screen, that's not necessarily when it was "printed". It > gets buffered, you know. If you want to time-check when various > sections get control, to find out what's eating the time, then > put the jiffie count into your kernel messages. > > A simple macro using the __FUNCTION__ string and the jiffie > count can go a long way towards finding out what's happening. > > For instance, I once had a problem with continuous interrupts > from a device, that couldn't be cleared, until the device was > initialized. That slowed the system to a stand-still until > I found that. The fix was easy, do some initialization before > attaching the interrupt, at least enough to quiet the board. > This board had an empty FPGA, whos bits need to be loaded > with a bit-banger to make it work. The pin connected to an > interrupt was just whatever-it-was-from-the-factory, before > the intelligence was loaded. That system took about a minute > for the first kernel message to be printed. Sometimes the > system was very quiet <forever> and needed to be kicked. > > > Cheers, > Dick Johnson > Penguin : Linux version 2.6.13 on an i686 machine (5589.55 > BogoMips). > Warning : 98.36% of all statistics are fiction. > > **************************************************************** > The information transmitted in this message is confidential and may > be privileged. Any review, retransmission, dissemination, or other > use of this information by persons or entities other than the > intended recipient is prohibited. If you are not the intended > recipient, please notify Analogic Corporation immediately - by > replying to this message or by sending an email to > DeliveryErrors@analogic.com - and destroy all copies of this > information, including any attachments, without reading or > disclosing them. > > Thank you.
Appreciate your advice and help. I finally tracked it down to the function called in init_module() in kernel/module.c.
/* Allow arches to frob section contents and sizes. */ err = module_frob_arch_sections(hdr, sechdrs, secstrings, mod);
which takes most of time (more then 99%) during module loading just as the reply from Semuel earlier.
Wilson Li
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