Messages in this thread | | | Date | Thu, 29 Feb 2024 08:37:55 +0800 | Subject | Re: [PATCH 0/4] printk_index: Fix false positives | From | Xiubo Li <> |
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On 2/28/24 22:00, Geert Uytterhoeven wrote: > Hi all, > > When printk-indexing is enabled, each printk() invocation emits a > pi_entry structure, containing the format string and other information > related to its location in the kernel sources. This is even true when > the printk() is protected by an always-false check, as is typically the > case for debug messages: while the actual code to print the message is > optimized out by the compiler, the pi_entry structure is still emitted. > Hence when debugging is disabled, this leads to the inclusion in the > index of lots of printk formats that cannot be emitted by the current > kernel. > > This series fixes that for the common debug helpers under include/. > It reduces the size of an arm64 defconfig kernel with > CONFIG_PRINTK_INDEX=y by ca. 1.5 MiB, or 28% of the overhead of > enabling CONFIG_PRINTK_INDEX=y. > > Notes: > - netdev_(v)dbg() and netif_(v)dbg() are not affected, as > net{dev,if}_printk() do not implement printk-indexing, except > for the single global internal instance of __netdev_printk(). > - This series fixes only debug code in global header files under > include/. There are more cases to fix in subsystem-specific header > files and in sources files. > > Thanks for your comments! > > Geert Uytterhoeven (4): > printk: Let no_printk() use _printk() > dev_printk: Add and use dev_no_printk() > dyndbg: Use *no_printk() helpers > ceph: Use no_printk() helper > > include/linux/ceph/ceph_debug.h | 18 +++++++----------- > include/linux/dev_printk.h | 25 +++++++++++++------------ > include/linux/dynamic_debug.h | 4 ++-- > include/linux/printk.h | 2 +- > 4 files changed, 23 insertions(+), 26 deletions(-) > This series LGTM.
Reviewed-by: Xiubo Li <xiubli@redhat.com>
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