On Friday 22 April 2005 01:02, Yum Rayan wrote:
> This patch reduces the stack usage of the function smc91c92_event() in
> smc91c92_cs driver from 3540 to 132. Currently this is the highest
> stack user in linux-2.6.12-rc2-mm3. I used a patched version of gcc
> 3.4.3 on i386 with -fno-unit-at-a-time disabled.
>
> The patch has only been compile tested. It would be nice to get
> feedback if someone that owns the hardware can actually test this
> patch.
>
> Acked-by: JЖrn Engel <[email protected]>
> Acked-by: Randy Dunlap <[email protected]>
> Signed-off-by: Yum Rayan <[email protected]>
>
> smc91c92_cs.c | 287 ++++++++++++++++++++++++++++++++++++++--------------------
> 1 files changed, 189 insertions(+), 98 deletions(-)
>
> diff -Nupr -X dontdiff
> linux-2.6.12-rc2-mm3.a/drivers/net/pcmcia/smc91c92_cs.c
> linux-2.6.12-rc2-mm3.b/drivers/net/pcmcia/smc91c92_cs.c
> --- linux-2.6.12-rc2-mm3.a/drivers/net/pcmcia/smc91c92_cs.c 2005-04-14
> 22:15:43.000000000 -0700
> +++ linux-2.6.12-rc2-mm3.b/drivers/net/pcmcia/smc91c92_cs.c 2005-04-20
> 18:12:00.000000000 -0700
> @@ -127,6 +127,12 @@ struct smc_private {
> int rx_ovrn;
> };
>
> +struct smc_cfg_mem {
> + tuple_t tuple;
> + cisparse_t parse;
> + u_char buf[255];
> +};
> +
> /* Special definitions for Megahertz multifunction cards */
> #define MEGAHERTZ_ISR 0x0380
>
> @@ -498,14 +504,24 @@ static int mhz_mfc_config(dev_link_t *li
> {
> struct net_device *dev = link->priv;
> struct smc_private *smc = netdev_priv(dev);
> - tuple_t tuple;
> - cisparse_t parse;
> - u_char buf[255];
> - cistpl_cftable_entry_t *cf = &parse.cftable_entry;
> + struct smc_cfg_mem *cfg_mem;
> + tuple_t *tuple;
> + cisparse_t *parse;
> + cistpl_cftable_entry_t *cf;
> + u_char *buf;
I do it this way:
int f()
{
- tuple_t tuple;
- cisparse_t parse;
- u_char buf[255];
+ struct {
+ tuple_t tuple;
+ cisparse_t parse;
+ u_char buf[255];
+ } local;
+ local = kmalloc(sizeof(*local),...); if(!local)...
...
- tuple.Attributes = tuple.TupleOffset = 0;
- tuple.TupleData = (cisdata_t *)buf;
- tuple.TupleDataMax = sizeof(buf);
+ local->tuple.Attributes = local->tuple.TupleOffset = 0;
+ local->tuple.TupleData = (cisdata_t *)local->buf;
+ local->tuple.TupleDataMax = sizeof(local->buf);
I see the following advantages:
1) struct is unnamed and local to function
2) Variables do not change their type, the just sit in local-> now.
I can just add 'local->' to each affected variable,
without "it was an object, now it is a pointer" changes.
No need to replace . with ->, remove &, etc.
3) I do not need to do this part of your patch which adds more locals:
+ tuple_t *tuple;
+ cisparse_t *parse;
+ cistpl_cftable_entry_t *cf;
+ u_char *buf;
...
+ tuple = &cfg_mem->tuple;
+ parse = &cfg_mem->parse;
+ buf = cfg_mem->buf;
4) in resulting asm one base pointer instead of many will require
less registers
Look into nfs4_proc_unlink_setup() for example.
I see that Trond do not use locally declared struct there,
but otherwise it is done as described above.
--
vda
-
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