Hi Mahesh, This feature's patches are very large, and I created a devel branch on sourceforge git tree for sharing the code with you. http://makedumpfile.git.sourceforge.net/git/gitweb.cgi?p=makedumpfile/makedumpfile;a=shortlog;h=refs/heads/filter-out-devel I commited all of your patches and my cleanup patches. If you notice some problems or cleate some patches, please let me know them. On Wed, 27 Jul 2011 11:39:44 +0530 Mahesh Jagannath Salgaonkar <mahesh at linux.vnet.ibm.com> wrote: > >> + * > >> + * This function uses dwfl API's to apply relocation before reading the > >> + * dwarf information from module debuginfo. > >> + * On success, this function sets the dwarf_info.elfd and dwarf_info.dwarfd > >> + * after applying relocation to module debuginfo. > >> + */ > >> +static int > >> +init_dwarf_info(void) > > > > Is the searching method of debuginfo file only for kernel module ? > > Or also for vmlinux ? > > Yes, the searching method is only for module debuginfo. For vmlinux we > set the dwarf_info.name_debuginfo before call to init_dwarf_info() and > we never call search routine dwfl_linux_kernel_report_offline() for > vmlinux. The routine dwfl_report_offline() applies the relocation on > specified debuginfo module. In case vmlinux it basically does nothing. > > > I feel this function is a little complex, and I'd like to make it simple. > > If only for kernel module, we can do it by separating the searching method > > from this function and calling it in case of kernel module. > > The init_dwarf_info() function gets called everytime when > get_debug_info() is called. The get_debug_info() is called multiple > times for same debuginfo file. This function tries to avoid the repeated > search for same debuginfo, hence the function is little complex. > - In case of kernel module the very first invocation of > init_dwarf_info() would call dwfl_linux_kernel_report_offline() which > will iterate over the available kernel modules and process the debuginfo > only for the module for which we are interested in. > - We set the dwarf_info.name_debuginfo with the debuginfo file name > found during the first invocation. > - The second invocation of init_dwarf_info() for same kernel module, > will find dwarf_info.name_debuginfo is already set and will avoid the > debuginfo search. In this case it will just apply relocation using > routine dwfl_report_offline(). > > This function does not have any special handling code for vmlinux. The > function is independent of whether it is called for vmlinux or kernel > module. In case of vmlinux this function has absolutely no side effects. If adding the searching method to the blow position and removing the code from init_dwarf_info(), I guess it makes the code simple. @ process_config_file() 9402 if (!set_dwarf_debuginfo(config->module_name, 9403 NULL, -1)) { 9404 ERRMSG("Skipping to next Module section\n"); 9405 skip_section = 1; 9406 free_config(config); 9407 continue; 9408 } 9409 << HERE >> Anyway, I need to investigate the code more. Thanks Ken'ichi Ohmichi
