LinuxLists.cc - [PATCH] isdn: reduce stack size of mISDN

2009-03-01 16:33:07

Subject: [PATCH] isdn: reduce stack size of mISDN_dsp

2009-03-01 16:51:52

Subject: Re: [PATCH] isdn: reduce stack size of mISDN_dsp

On Sun, Mar 01, 2009 at 05:32:50PM +0100, Frank Seidel wrote:
> From: Frank Seidel <[email protected]>
>
> Reduce stack size memory footprint of mISDN_dsp.
> (From 1468 bytes for dsp_cmx_send on i386 down
> to 44).
>

I do not think we can use a static buffer here,
we may have multiple instances.

> Signed-off-by: Frank Seidel <[email protected]>
> ---
> drivers/isdn/mISDN/dsp_cmx.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> --- a/drivers/isdn/mISDN/dsp_cmx.c
> +++ b/drivers/isdn/mISDN/dsp_cmx.c
> @@ -1592,7 +1592,8 @@ dsp_cmx_send(void *arg)
> struct dsp_conf_member *member;
> struct dsp *dsp;
> int mustmix, members;
> - s32 mixbuffer[MAX_POLL+100], *c;
> + static s32 mixbuffer[MAX_POLL+100];
> + s32 *c;
> u8 *p, *q;
> int r, rr;
> int jittercheck = 0, delay, i;

--
Karsten Keil
SuSE Labs
ISDN and VOIP development
SUSE LINUX Products GmbH, Maxfeldstr.5 90409 Nuernberg, GF: Markus Rex, HRB 16746 (AG Nuernberg)

2009-03-01 16:53:57

by Frank Seidel

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Subject: Re: [PATCH] isdn: reduce stack size of mISDN_dsp

On 03/01/2009 05:51 PM, Karsten Keil wrote:
> I do not think we can use a static buffer here,
> we may have multiple instances.

Oh, i see. So i'll redo the patch with
kmalloc/kfree.

Thanks,
Frank

2009-03-01 17:10:39

by Frank Seidel

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Subject: [PATCHv2] isdn: reduce stack size of mISDN_dsp

From: Frank Seidel <[email protected]>

Reduce stack size memory footprint of mISDN_dsp.
(From 1468 bytes for dsp_cmx_send on i386 down
to 44).

Signed-off-by: Frank Seidel <[email protected]>
---
drivers/isdn/mISDN/dsp_cmx.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)

--- a/drivers/isdn/mISDN/dsp_cmx.c
+++ b/drivers/isdn/mISDN/dsp_cmx.c
@@ -1592,13 +1592,21 @@ dsp_cmx_send(void *arg)
struct dsp_conf_member *member;
struct dsp *dsp;
int mustmix, members;
- s32 mixbuffer[MAX_POLL+100], *c;
+ s32 *mixbuffer;
+ s32 *c;
u8 *p, *q;
int r, rr;
int jittercheck = 0, delay, i;
u_long flags;
u16 length, count;

+ mixbuffer = kmalloc(sizeof(*mixbuffer) * (MAX_POLL + 100), GFP_KERNEL);
+ if (!mixbuffer) {
+ printk(KERN_ERR "mISDN_dsp: cannot allocate buffer(%s)\n",
+ __func__);
+ return;
+ }
+
/* lock */
spin_lock_irqsave(&dsp_lock, flags);

@@ -1811,6 +1819,8 @@ dsp_cmx_send(void *arg)

/* unlock */
spin_unlock_irqrestore(&dsp_lock, flags);
+
+ kfree(mixbuffer);
}

/*

2009-03-01 19:55:06

by Karsten Keil

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Subject: Re: [PATCHv2] isdn: reduce stack size of mISDN_dsp

On Sun, Mar 01, 2009 at 06:10:24PM +0100, Frank Seidel wrote:
> From: Frank Seidel <[email protected]>
>
> Reduce stack size memory footprint of mISDN_dsp.
> (From 1468 bytes for dsp_cmx_send on i386 down
> to 44).

Looks safer and has the same function as before, but
I think we should work on a better solution later, which
use one buffer per instance and allocate it on creation time.
Andreas, what do you think ?

>
> Signed-off-by: Frank Seidel <[email protected]>
> ---
> drivers/isdn/mISDN/dsp_cmx.c | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
> --- a/drivers/isdn/mISDN/dsp_cmx.c
> +++ b/drivers/isdn/mISDN/dsp_cmx.c
> @@ -1592,13 +1592,21 @@ dsp_cmx_send(void *arg)
> struct dsp_conf_member *member;
> struct dsp *dsp;
> int mustmix, members;
> - s32 mixbuffer[MAX_POLL+100], *c;
> + s32 *mixbuffer;
> + s32 *c;
> u8 *p, *q;
> int r, rr;
> int jittercheck = 0, delay, i;
> u_long flags;
> u16 length, count;
>
> + mixbuffer = kmalloc(sizeof(*mixbuffer) * (MAX_POLL + 100), GFP_KERNEL);
> + if (!mixbuffer) {
> + printk(KERN_ERR "mISDN_dsp: cannot allocate buffer(%s)\n",
> + __func__);
> + return;
> + }
> +
> /* lock */
> spin_lock_irqsave(&dsp_lock, flags);
>
> @@ -1811,6 +1819,8 @@ dsp_cmx_send(void *arg)
>
> /* unlock */
> spin_unlock_irqrestore(&dsp_lock, flags);
> +
> + kfree(mixbuffer);
> }
>
> /*

--
Karsten Keil