On Sat, 12 Jul 2014 16:43:26 +0200 Mathias Krause <[email protected]> wrote:
> The memory used for functions marked with __init will be released after > initialization, albeit static data referenced by such code will not, if > not explicitly marked this way, too. This is especially true for format > strings used in messages printed by such code. Those are not marked and > therefore will survive the __init cleanup -- dangling in memory without > ever being referenced again. > > Ideally we would like the compiler to automatically recognise such > constructs but it does not and it's not as simple as it might sound, as > strings used in initialization code might latter still be used, e.g. as > a slab cache name. Therefore we need to explicitly mark the strings we > want to release together with the function itself. > > For a seamless integration of the necessary __init_str() / __exit_str() > macros to mark the format strings, this patch provides new variants of > the well known pr_<level>() macros as pi_<level>() for __init code and > pe_<level>() for __exit code. Changing existing code should thereby be > as simple as changing a single letter. > > For code that cannot be changed to use the pi_<level>() / pe_<level>() > macros printk_init() and printk_exit() macros are provided, too. > > One remark, though: We cannot provide appropriate p[ie]_debug() macros > for the CONFIG_DYNAMIC_DEBUG case as there is (currently) no way to > remove entries from dyndbg after initialization. But supporting that > scenario would require more work (and code), therefore not necessarily > justifying the memory savings. I assume that if a programmer gets this wrong, CONFIG_DEBUG_SECTION_MISMATCH will detect and report the error? Please thoroughly test this if you have not done so. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
