On 17.03.25 14:56, Heiko Carstens wrote:
On Mon, Mar 17, 2025 at 12:22:46PM +0100, Wenjia Zhang wrote:
On 15.03.25 07:25, I Hsin Cheng wrote:
The variable "polled" in smc_wr_tx_tasklet_fn is a counter to determine
whether the loop has been executed for the first time. Refactor the type
of "polled" from "int" to "bool" can reduce the size of generated code
size by 12 bytes shown with the test below
$ ./scripts/bloat-o-meter vmlinux_old vmlinux_new
add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-12 (-12)
Function old new delta
smc_wr_tx_tasklet_fn 1076 1064 -12
Total: Before=24795091, After=24795079, chg -0.00%
In some configuration, the compiler will complain this function for
exceeding 1024 bytes for function stack, this change can at least reduce
the size by 12 bytes within manner.
The code itself looks good. However, I’m curious about the specific
situation where the compiler complained. Also, compared to exceeding the
function stack limit by 1024 bytes, I don’t see how saving 12 bytes would
bring any significant benefit.
The patch description doesn't make sense: bloat-a-meter prints the _text
size_ difference of two kernels, which really has nothing to do with
potential stack size savings.
If there are any changes in stack size with this patch is unknown; at least
if you rely only on the patch description.
You may want to have a look at scripts/stackusage and scripts/stackdelta.
@Heiko, thank you for pointing it out!
Even if the potential stack size saving of 12 bytes were true, I still
don’t see how it would benefit our code, let alone justify the incorrect
argument.
