On Mon, 25 May 2020, Maciej W. Rozycki wrote:

On Mon, 25 May 2020, Mikulas Patocka wrote:

quoted

quoted

quoted

The functions __raw_read* are already extern inline, so the compiler will 
inline/noinline them depending on the macros trivial_io_bw and 
trivial_io_lq - so we can just call them from read*_relaxed without 
repeating the extern inline pattern.

 The whole point of this peculiar arrangement for cooked accessors is to 
avoid having barriers inserted inline around out-of-line calls to raw 
accessors,

I see, but why do we want to avoid that? Linux kernel has no binary 
compatibility, so it doesn't matter if the barriers are inlined in the 
drivers or not.

 It does matter as it expands code unnecessarily (at all call sites), as I 
noted in the original review.  This has nothing to do with compatibility.

quoted

Anyway, I've sent a next version of the patch that makes read*_relaxed 
extern inline.

 Thanks, I'll have a look.  And now that you have this update, please run 
`size' on ALPHA_GENERIC `vmlinux', preferably monolithic, to see what the 
difference is between `read*_relaxed' handlers `static inline' and keyed 
with `*trivial_rw_*'.

  Maciej

The patch with static inline:
   text    data     bss     dec     hex filename
124207762       75953010        5426432 205587204       c410304 vmlinux

The patch with extern inline:
   text    data     bss     dec     hex filename
124184422       75953474        5426432 205564328       c40a9a8 vmlinux

(I've sent version 7 of the patch because I misnamed the "write_relaxed" 
function in version 6).

Mikulas