Thread (9 messages) 9 messages, 5 authors, 2017-09-25

Re: [PATCH] wireless: iwlegacy: make const array static to shink object code size Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit

From: Julia Lawall <hidden>
Date: 2017-09-22 07:23:20
Also in: kernel-janitors, linux-wireless, lkml


On Thu, 21 Sep 2017, Colin King wrote:
From: Colin Ian King <redacted>

Don't populate const array ac_to_fifo on the stack in an inlined
function, instead make it static.  Makes the object code smaller
by over 800 bytes:

   text	   data	    bss	    dec	    hex	filename
 159029	  33154	   1216	 193399	  2f377	4965-mac.o

   text	   data	    bss	    dec	    hex	filename
 158122	  33250	   1216	 192588	  2f04c	4965-mac.o

(gcc version 7.2.0 x86_64)
Gcc 7 must be much more aggressive about inlining than gcc 4.  Here is the
change that I got on this file:

     text          data     bss     dec     hex filename
-   76346          1494     152   77992   130a8 drivers/net/wireless/intel/iwlegacy/4965-mac.o
+   76298          1494     152   77944   13078 drivers/net/wireless/intel/iwlegacy/4965-mac.o
decrease of 48

julia
quoted hunk ↗ jump to hunk
Signed-off-by: Colin Ian King <redacted>
---
 drivers/net/wireless/intel/iwlegacy/4965-mac.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/wireless/intel/iwlegacy/4965-mac.c b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
index de9b6522c43f..65eba2c24292 100644
--- a/drivers/net/wireless/intel/iwlegacy/4965-mac.c
+++ b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
@@ -1480,7 +1480,7 @@ il4965_get_ac_from_tid(u16 tid)
 static inline int
 il4965_get_fifo_from_tid(u16 tid)
 {
-	const u8 ac_to_fifo[] = {
+	static const u8 ac_to_fifo[] = {
 		IL_TX_FIFO_VO,
 		IL_TX_FIFO_VI,
 		IL_TX_FIFO_BE,
--
2.14.1

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