* [patch 1/3] Add generic routine for parsing map-like options on kernel cmd-line
[not found] <20071218220505.828395321@bohmer.net>
@ 2007-12-18 22:05 ` Remy Bohmer
2007-12-19 17:00 ` Sven-Thorsten Dietrich
2007-12-18 22:05 ` [patch 2/3] Enable setting of IRQ-thread priorities from kernel cmdline Remy Bohmer
2007-12-18 22:05 ` [patch 3/3] " Remy Bohmer
2 siblings, 1 reply; 4+ messages in thread
From: Remy Bohmer @ 2007-12-18 22:05 UTC (permalink / raw)
To: Steven Rostedt
Cc: Arnaldo Carvalho de Melo, Ingo Molnar, Juergen Beisert,
Darren Hart, linux-rt-users, Remy Bohmer
[-- Attachment #1: add-map-functionality-to-kernel-cmdline.patch --]
[-- Type: text/plain, Size: 3187 bytes --]
This patch adds a generic routine to the kernel, so that a map of
settings can be entered on the kernel commandline.
Signed-off-by: Remy Bohmer <linux@bohmer.net>
---
---
include/linux/kernel.h | 1
lib/cmdline.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 59 insertions(+)
Index: linux-2.6.24-rc5-rt1/include/linux/kernel.h
===================================================================
--- linux-2.6.24-rc5-rt1.orig/include/linux/kernel.h 2007-12-18 21:32:09.000000000 +0100
+++ linux-2.6.24-rc5-rt1/include/linux/kernel.h 2007-12-18 21:33:58.000000000 +0100
@@ -164,6 +164,7 @@ extern int vsscanf(const char *, const c
extern int get_option(char **str, int *pint);
extern char *get_options(const char *str, int nints, int *ints);
+extern int get_map_option(const char *str, const char *key, int *pint);
extern unsigned long long memparse(char *ptr, char **retptr);
extern int core_kernel_text(unsigned long addr);
Index: linux-2.6.24-rc5-rt1/lib/cmdline.c
===================================================================
--- linux-2.6.24-rc5-rt1.orig/lib/cmdline.c 2007-10-09 22:31:38.000000000 +0200
+++ linux-2.6.24-rc5-rt1/lib/cmdline.c 2007-12-18 21:33:58.000000000 +0100
@@ -15,6 +15,7 @@
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/string.h>
+#include <asm/setup.h>
/*
* If a hyphen was found in get_option, this will handle the
@@ -114,6 +115,63 @@ char *get_options(const char *str, int n
}
/**
+ * get_map_option - Parse integer from an option map
+ *
+ * This function parses an integer from an option map like
+ * some_map=key1:99,key2:98,...,keyN:NN,NN
+ * Only the value of the first match is returned, or if no
+ * key option is given (key = NULL) the value of the first
+ * field without a ':' is returned.
+ *
+ * @str: option string
+ * @key: The key inside the map, can be NULL
+ * @pint: (output) integer value parsed from the map @str
+ *
+ * Return values:
+ * 0 - no int in string
+ * 1 - int found
+ */
+int get_map_option(const char *str, const char *key, int *pint)
+{
+ char buf[COMMAND_LINE_SIZE];
+ char *p, *substr;
+ int found = 0;
+
+ /* We must copy the string to the stack, because strsep()
+ changes it.*/
+ strncpy(buf, str, COMMAND_LINE_SIZE);
+ buf[COMMAND_LINE_SIZE-1] = '\0';
+
+ p = buf;
+ substr = strsep(&p, ",");
+ while ((!found) && (substr != NULL)) {
+ if (strlen(substr) != 0) {
+ if (key == NULL) {
+ /* Check for the absence of any ':' */
+ if (strchr(substr, ':') == NULL) {
+ sscanf(substr, "%d", pint);
+ found = 1;
+ }
+ } else {
+ /* check if the first part of the key matches */
+ if (!strncmp(substr, key, strlen(key))) {
+ substr += strlen(key);
+ /* Now the next char must be a ':',
+ if not, search for the next match */
+ if (*substr == ':') {
+ substr++;
+ sscanf(substr, "%d", pint);
+ found = 1;
+ }
+ }
+ }
+ }
+ substr = strsep(&p, ",");
+ }
+ return found;
+}
+
+/**
* memparse - parse a string with mem suffixes into a number
* @ptr: Where parse begins
* @retptr: (output) Pointer to next char after parse completes
--
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [patch 1/3] Add generic routine for parsing map-like options on kernel cmd-line
2007-12-18 22:05 ` [patch 1/3] Add generic routine for parsing map-like options on kernel cmd-line Remy Bohmer
@ 2007-12-19 17:00 ` Sven-Thorsten Dietrich
0 siblings, 0 replies; 4+ messages in thread
From: Sven-Thorsten Dietrich @ 2007-12-19 17:00 UTC (permalink / raw)
To: Remy Bohmer
Cc: Steven Rostedt, Arnaldo Carvalho de Melo, Ingo Molnar,
Juergen Beisert, Darren Hart, linux-rt-users, Remy Bohmer
On Tue, 2007-12-18 at 23:05 +0100, Remy Bohmer wrote:
> plain text document attachment
> (add-map-functionality-to-kernel-cmdline.patch)
> This patch adds a generic routine to the kernel, so that a map of
> settings can be entered on the kernel commandline.
>
Hi Remy,
this might be of general interest - you should consider copying LKML for
feedback.
Regards,
Sven
> Signed-off-by: Remy Bohmer <linux@bohmer.net>
>
> ---
> ---
> include/linux/kernel.h | 1
> lib/cmdline.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 59 insertions(+)
>
> Index: linux-2.6.24-rc5-rt1/include/linux/kernel.h
> ===================================================================
> --- linux-2.6.24-rc5-rt1.orig/include/linux/kernel.h 2007-12-18 21:32:09.000000000 +0100
> +++ linux-2.6.24-rc5-rt1/include/linux/kernel.h 2007-12-18 21:33:58.000000000 +0100
> @@ -164,6 +164,7 @@ extern int vsscanf(const char *, const c
>
> extern int get_option(char **str, int *pint);
> extern char *get_options(const char *str, int nints, int *ints);
> +extern int get_map_option(const char *str, const char *key, int *pint);
> extern unsigned long long memparse(char *ptr, char **retptr);
>
> extern int core_kernel_text(unsigned long addr);
> Index: linux-2.6.24-rc5-rt1/lib/cmdline.c
> ===================================================================
> --- linux-2.6.24-rc5-rt1.orig/lib/cmdline.c 2007-10-09 22:31:38.000000000 +0200
> +++ linux-2.6.24-rc5-rt1/lib/cmdline.c 2007-12-18 21:33:58.000000000 +0100
> @@ -15,6 +15,7 @@
> #include <linux/module.h>
> #include <linux/kernel.h>
> #include <linux/string.h>
> +#include <asm/setup.h>
>
> /*
> * If a hyphen was found in get_option, this will handle the
> @@ -114,6 +115,63 @@ char *get_options(const char *str, int n
> }
>
> /**
> + * get_map_option - Parse integer from an option map
> + *
> + * This function parses an integer from an option map like
> + * some_map=key1:99,key2:98,...,keyN:NN,NN
> + * Only the value of the first match is returned, or if no
> + * key option is given (key = NULL) the value of the first
> + * field without a ':' is returned.
> + *
> + * @str: option string
> + * @key: The key inside the map, can be NULL
> + * @pint: (output) integer value parsed from the map @str
> + *
> + * Return values:
> + * 0 - no int in string
> + * 1 - int found
> + */
> +int get_map_option(const char *str, const char *key, int *pint)
> +{
> + char buf[COMMAND_LINE_SIZE];
> + char *p, *substr;
> + int found = 0;
> +
> + /* We must copy the string to the stack, because strsep()
> + changes it.*/
> + strncpy(buf, str, COMMAND_LINE_SIZE);
> + buf[COMMAND_LINE_SIZE-1] = '\0';
> +
> + p = buf;
> + substr = strsep(&p, ",");
> + while ((!found) && (substr != NULL)) {
> + if (strlen(substr) != 0) {
> + if (key == NULL) {
> + /* Check for the absence of any ':' */
> + if (strchr(substr, ':') == NULL) {
> + sscanf(substr, "%d", pint);
> + found = 1;
> + }
> + } else {
> + /* check if the first part of the key matches */
> + if (!strncmp(substr, key, strlen(key))) {
> + substr += strlen(key);
> + /* Now the next char must be a ':',
> + if not, search for the next match */
> + if (*substr == ':') {
> + substr++;
> + sscanf(substr, "%d", pint);
> + found = 1;
> + }
> + }
> + }
> + }
> + substr = strsep(&p, ",");
> + }
> + return found;
> +}
> +
> +/**
> * memparse - parse a string with mem suffixes into a number
> * @ptr: Where parse begins
> * @retptr: (output) Pointer to next char after parse completes
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* [patch 2/3] Enable setting of IRQ-thread priorities from kernel cmdline
[not found] <20071218220505.828395321@bohmer.net>
2007-12-18 22:05 ` [patch 1/3] Add generic routine for parsing map-like options on kernel cmd-line Remy Bohmer
@ 2007-12-18 22:05 ` Remy Bohmer
2007-12-18 22:05 ` [patch 3/3] " Remy Bohmer
2 siblings, 0 replies; 4+ messages in thread
From: Remy Bohmer @ 2007-12-18 22:05 UTC (permalink / raw)
To: Steven Rostedt
Cc: Arnaldo Carvalho de Melo, Ingo Molnar, Juergen Beisert,
Darren Hart, linux-rt-users, Remy Bohmer
[-- Attachment #1: changing_interrupt_prios_from_kernel_cmdline.patch --]
[-- Type: text/plain, Size: 7916 bytes --]
The RT-patch originally creates all its IRQ-threads at priority 50.
Of course, this is not a usable default for many realtime systems
and therefor these priorities has to be tuneable for each RT-system.
But, currently there is no way within the kernel to adjust this to
the needs of the user. Some scripts are floating around to do this
from userspace, but for several applications the priorities should
already be set properly by the kernel itself before userland is
started.
This patch changes this by adding a kernel cmd-line option that can
handle a map of priorities.
It is based on the name of the driver that requests an interrupt, it
does NOT use the IRQ-ID to prioritize a certain IRQ thread.
This is designed this way because across several hardware-boards the
IRQ-IDs can change, but not necessarily the drivers
(interrupt handlers) name.
Remarks:
* There is a check for conflicts added, for situations where
IRQ-sharing is detected with different priorities requested
on the kernel cmd-line.
* Priorities are only set at creation time of the IRQ-thread.
* If userland overrules, it is NOT restored by this code.
* if no new kernel cmdline options are given, the kernel works
as before, and all IRQ-threads start at 50.
* No wildcards are supported on the cmdline.
See kernel/Documentation/kernel-parameters.txt for usage info.
Signed-off-by: Remy Bohmer <linux@bohmer.net>
---
Documentation/kernel-parameters.txt | 7 ++
include/linux/irq.h | 1
kernel/irq/manage.c | 101 ++++++++++++++++++++++++++++++++----
3 files changed, 98 insertions(+), 11 deletions(-)
Index: linux-2.6.24-rc5-rt1/Documentation/kernel-parameters.txt
===================================================================
--- linux-2.6.24-rc5-rt1.orig/Documentation/kernel-parameters.txt 2007-12-18 22:09:13.000000000 +0100
+++ linux-2.6.24-rc5-rt1/Documentation/kernel-parameters.txt 2007-12-18 22:09:16.000000000 +0100
@@ -799,6 +799,13 @@ and is between 256 and 4096 characters.
ips= [HW,SCSI] Adaptec / IBM ServeRAID controller
See header of drivers/scsi/ips.c.
+ irq_pmap= [IRQ-threading] List of priorities each interrupt
+ thread must have.
+ Format: irq_pmap=megasas:90,eth0:40,50
+ The first field without ':', is the default prio.
+ If this cmdline argument is ommitted, every thread
+ runs at prio 50.
+
ports= [IP_VS_FTP] IPVS ftp helper module
Default is 21.
Up to 8 (IP_VS_APP_MAX_PORTS) ports
Index: linux-2.6.24-rc5-rt1/include/linux/irq.h
===================================================================
--- linux-2.6.24-rc5-rt1.orig/include/linux/irq.h 2007-12-18 22:09:13.000000000 +0100
+++ linux-2.6.24-rc5-rt1/include/linux/irq.h 2007-12-18 22:09:16.000000000 +0100
@@ -169,6 +169,7 @@ struct irq_desc {
unsigned int irqs_unhandled;
unsigned long last_unhandled; /* Aging timer for unhandled count */
struct task_struct *thread;
+ int rt_prio;
wait_queue_head_t wait_for_handler;
cycles_t timestamp;
raw_spinlock_t lock;
Index: linux-2.6.24-rc5-rt1/kernel/irq/manage.c
===================================================================
--- linux-2.6.24-rc5-rt1.orig/kernel/irq/manage.c 2007-12-18 22:09:13.000000000 +0100
+++ linux-2.6.24-rc5-rt1/kernel/irq/manage.c 2007-12-18 22:15:43.000000000 +0100
@@ -13,9 +13,19 @@
#include <linux/kthread.h>
#include <linux/syscalls.h>
#include <linux/interrupt.h>
+#include <linux/list.h>
#include "internals.h"
+
+#ifdef CONFIG_PREEMPT_HARDIRQS
+
+static char *cmdline;
+static int default_prio = MAX_USER_RT_PRIO/2;
+
+#endif
+
+
#ifdef CONFIG_SMP
/**
@@ -260,7 +270,7 @@ void recalculate_desc_flags(struct irq_d
desc->status |= IRQ_NODELAY;
}
-static int start_irq_thread(int irq, struct irq_desc *desc);
+static int start_irq_thread(int irq, struct irq_desc *desc, int prio);
/*
* Internal function that tells the architecture code whether a
@@ -293,6 +303,8 @@ void compat_irq_chip_set_default_handler
desc->handle_irq = NULL;
}
+static int get_irq_prio(const char *name);
+
/*
* Internal function to register an irqaction - typically used to
* allocate special interrupts that are part of the architecture.
@@ -328,7 +340,7 @@ int setup_irq(unsigned int irq, struct i
}
if (!(new->flags & IRQF_NODELAY))
- if (start_irq_thread(irq, desc))
+ if (start_irq_thread(irq, desc, get_irq_prio(new->name)))
return -ENOMEM;
/*
* The following block of code has to be executed atomically
@@ -811,11 +823,7 @@ static int do_irqd(void * __desc)
#endif
current->flags |= PF_NOFREEZE | PF_HARDIRQ;
- /*
- * Set irq thread priority to SCHED_FIFO/50:
- */
- param.sched_priority = MAX_USER_RT_PRIO/2;
-
+ param.sched_priority = desc->rt_prio;
sys_sched_setscheduler(current->pid, SCHED_FIFO, ¶m);
while (!kthread_should_stop()) {
@@ -850,11 +858,20 @@ static int do_irqd(void * __desc)
static int ok_to_create_irq_threads;
-static int start_irq_thread(int irq, struct irq_desc *desc)
+static int start_irq_thread(int irq, struct irq_desc *desc, int prio)
{
- if (desc->thread || !ok_to_create_irq_threads)
+ if (!ok_to_create_irq_threads)
return 0;
+ if (desc->thread) {
+ if (desc->rt_prio != prio)
+ printk(KERN_NOTICE
+ "irqd: Interrupt sharing detected with "
+ "conflicting thread priorities, irq:%d!\n", irq);
+ return 0;
+ }
+
+ desc->rt_prio = prio;
desc->thread = kthread_create(do_irqd, desc, "IRQ-%d", irq);
if (!desc->thread) {
printk(KERN_ERR "irqd: could not create IRQ thread %d!\n", irq);
@@ -881,13 +898,13 @@ void __init init_hardirqs(void)
irq_desc_t *desc = irq_desc + i;
if (desc->action && !(desc->status & IRQ_NODELAY))
- start_irq_thread(i, desc);
+ start_irq_thread(i, desc, get_irq_prio(NULL));
}
}
#else
-static int start_irq_thread(int irq, struct irq_desc *desc)
+static int start_irq_thread(int irq, struct irq_desc *desc, int prio)
{
return 0;
}
@@ -901,3 +918,65 @@ void __init early_init_hardirqs(void)
for (i = 0; i < NR_IRQS; i++)
init_waitqueue_head(&irq_desc[i].wait_for_handler);
}
+
+#ifdef CONFIG_PREEMPT_HARDIRQS
+
+/*
+ * Lookup the interrupt thread priority
+ * A map for the priorities can be given on the kernel commandline.
+ * if name is NULL, or no kernel commandline options is given, the default
+ * prio is used, which is either MAX_PRIO/2, or the default given on the
+ * kernel commandline.
+ */
+static int get_irq_prio(const char *name)
+{
+ int prio = default_prio; /* Set the default for all threads */
+
+ /* If no commandline options, use thread prio defaults the old style.*/
+ if (!cmdline)
+ return prio;
+
+ if (!get_map_option(cmdline, name, &prio)) {
+ prio = default_prio;
+ if (name != NULL)
+ printk(KERN_INFO
+ "No IRQ-priority specified for '%s', " \
+ "using default(=%d)\n", name, prio);
+ } else {
+ if ((prio <= 0) || (prio >= MAX_USER_RT_PRIO))
+ prio = default_prio;
+
+ if (name != NULL)
+ printk(KERN_INFO "Using IRQ-priority %d for '%s'\n",
+ prio, name);
+ }
+ return prio;
+}
+
+/*
+ * Store the pointer to the arguments in a global var, and store the
+ * default prio globally
+ */
+static int __init irq_prio_map_setup(char *str)
+{
+ if (!str) /* sanity check */
+ return 1;
+
+ cmdline = str; /* store it for later use */
+ default_prio = get_irq_prio(NULL);
+
+ printk(KERN_INFO "Default IRQ-priority: %d\n", default_prio);
+ return 1;
+}
+
+/*
+ * The commandline looks like this: irq_pmap=megasas:90,eth0:40,50
+ * The first field without the ':' is used as the default for all irq-threads.
+ * There is a check for conflicts on irq-sharing.
+ * The priorities are only set on creation of the interrupt threads, thus at
+ * the time a driver uses a certain interrupt thread for the first time.
+ * Unknown or redundant fields are ignored.
+ */
+__setup("irq_pmap=", irq_prio_map_setup);
+
+#endif
--
^ permalink raw reply [flat|nested] 4+ messages in thread* [patch 3/3] Enable setting of IRQ-thread priorities from kernel cmdline.
[not found] <20071218220505.828395321@bohmer.net>
2007-12-18 22:05 ` [patch 1/3] Add generic routine for parsing map-like options on kernel cmd-line Remy Bohmer
2007-12-18 22:05 ` [patch 2/3] Enable setting of IRQ-thread priorities from kernel cmdline Remy Bohmer
@ 2007-12-18 22:05 ` Remy Bohmer
2 siblings, 0 replies; 4+ messages in thread
From: Remy Bohmer @ 2007-12-18 22:05 UTC (permalink / raw)
To: Steven Rostedt
Cc: Arnaldo Carvalho de Melo, Ingo Molnar, Juergen Beisert,
Darren Hart, linux-rt-users, Remy Bohmer
[-- Attachment #1: changing_softirq_prios_from_kernel_cmdline.patch --]
[-- Type: text/plain, Size: 6492 bytes --]
The RT-patch originally creates all its softirq-threads at
priority 50. Of course, this is not a usable default for many
realtime systems and therefor these priorities has to be tuneable
for each RT-system. But, currently there is no way within the
kernel to adjust this to the needs of the user. Some scripts
are floating around to do this from userspace, but for several
applications the priorities should already be set properly by
the kernel itself before userland is started.
This patch changes this by adding a kernel cmd-line option that
can handle a map of priorities.
Remarks:
* Priorities are only set at creation time of the softirq.
* Priorities has to be set per-cpu.
* If userland overrules, it is NOT restored by this code.
* if no new kernel cmdline options are given, the kernel works
as before, and all softirqs start at 50.
* No wildcards are supported on the cmdline.
See kernel/Documentation/kernel-parameters.txt for usage info.
Signed-off-by: Remy Bohmer <linux@bohmer.net>
---
Documentation/kernel-parameters.txt | 11 +++
kernel/softirq.c | 105 ++++++++++++++++++++++++++++++------
2 files changed, 99 insertions(+), 17 deletions(-)
Index: linux-2.6.24-rc5-rt1/Documentation/kernel-parameters.txt
===================================================================
--- linux-2.6.24-rc5-rt1.orig/Documentation/kernel-parameters.txt 2007-12-18 22:06:11.000000000 +0100
+++ linux-2.6.24-rc5-rt1/Documentation/kernel-parameters.txt 2007-12-18 22:07:19.000000000 +0100
@@ -806,6 +806,17 @@ and is between 256 and 4096 characters.
If this cmdline argument is ommitted, every thread
runs at prio 50.
+ sirq_pmap= [IRQ-threading] List of priorities each softirq
+ thread must have.
+ Format: sirq_pmap=block/0:90,sched/0:75,50
+ The priorities have to be specified per-cpu.
+ The first field without ':', is the default prio.
+ The names have to match the softirq_names[] table in
+ kernel/softirq.c, (thus without 'softirq-' prefix) to
+ keep the cmd-line short.
+ If this cmdline argument is ommitted, every softirq
+ runs at prio 50.
+
ports= [IP_VS_FTP] IPVS ftp helper module
Default is 21.
Up to 8 (IP_VS_APP_MAX_PORTS) ports
Index: linux-2.6.24-rc5-rt1/kernel/softirq.c
===================================================================
--- linux-2.6.24-rc5-rt1.orig/kernel/softirq.c 2007-12-18 22:06:11.000000000 +0100
+++ linux-2.6.24-rc5-rt1/kernel/softirq.c 2007-12-18 22:08:54.000000000 +0100
@@ -66,6 +66,10 @@ struct softirqdata {
static DEFINE_PER_CPU(struct softirqdata [MAX_SOFTIRQ], ksoftirqd);
+static char *cmdline;
+static int default_prio = MAX_USER_RT_PRIO/2;
+
+
#ifdef CONFIG_PREEMPT_SOFTIRQS
/*
* Preempting the softirq causes cases that would not be a
@@ -770,10 +774,28 @@ EXPORT_SYMBOL(tasklet_unlock_wait);
#endif
+static const char *softirq_names [] =
+{
+ [HI_SOFTIRQ] = "high",
+ [SCHED_SOFTIRQ] = "sched",
+ [TIMER_SOFTIRQ] = "timer",
+ [NET_TX_SOFTIRQ] = "net-tx",
+ [NET_RX_SOFTIRQ] = "net-rx",
+ [BLOCK_SOFTIRQ] = "block",
+ [TASKLET_SOFTIRQ] = "tasklet",
+#ifdef CONFIG_HIGH_RES_TIMERS
+ [HRTIMER_SOFTIRQ] = "hrtimer",
+#endif
+ [RCU_SOFTIRQ] = "rcu",
+};
+
+static int get_softirq_prio(const char *name);
+
static int ksoftirqd(void * __data)
{
- struct sched_param param = { .sched_priority = MAX_USER_RT_PRIO/2 };
+ struct sched_param param = { 0, };
struct softirqdata *data = __data;
+ char buf[50];
u32 softirq_mask = (1 << data->nr);
struct softirq_action *h;
int cpu = data->cpu;
@@ -781,8 +803,12 @@ static int ksoftirqd(void * __data)
#ifdef CONFIG_PREEMPT_SOFTIRQS
init_waitqueue_head(&data->wait);
#endif
-
+ /* Lookup the priority of this softirq, and set the prio accordingly */
+ snprintf(buf, sizeof(buf), "%s/%lu",
+ softirq_names[data->nr], data->cpu);
+ param.sched_priority = get_softirq_prio(buf);
sys_sched_setscheduler(current->pid, SCHED_FIFO, ¶m);
+
current->flags |= PF_SOFTIRQ;
set_current_state(TASK_INTERRUPTIBLE);
@@ -911,21 +937,6 @@ void takeover_tasklets(unsigned int cpu)
}
#endif /* CONFIG_HOTPLUG_CPU */
-static const char *softirq_names [] =
-{
- [HI_SOFTIRQ] = "high",
- [SCHED_SOFTIRQ] = "sched",
- [TIMER_SOFTIRQ] = "timer",
- [NET_TX_SOFTIRQ] = "net-tx",
- [NET_RX_SOFTIRQ] = "net-rx",
- [BLOCK_SOFTIRQ] = "block",
- [TASKLET_SOFTIRQ] = "tasklet",
-#ifdef CONFIG_HIGH_RES_TIMERS
- [HRTIMER_SOFTIRQ] = "hrtimer",
-#endif
- [RCU_SOFTIRQ] = "rcu",
-};
-
static int __cpuinit cpu_callback(struct notifier_block *nfb,
unsigned long action,
void *hcpu)
@@ -1051,3 +1062,63 @@ int on_each_cpu(void (*func) (void *info
}
EXPORT_SYMBOL(on_each_cpu);
#endif
+
+/*
+ * Lookup the softirq thread priority.
+ * A map for the priorities can be given on the kernel commandline.
+ * if name is NULL, or no kernel commandline options is given, the default
+ * prio is returned, which is either MAX_PRIO/2, or the default given on the
+ * kernel commandline.
+ */
+static int get_softirq_prio(const char *name)
+{
+ int prio = default_prio; /* Set the default for all threads */
+
+ /* If no commandline options, use thread prio defaults the old style.*/
+ if (!cmdline)
+ return prio;
+
+ if (!get_map_option(cmdline, name, &prio)) {
+ prio = default_prio;
+ if (name != NULL)
+ printk(KERN_INFO
+ "No priority specified for 'softirq-%s', " \
+ "using default(=%d)\n", name, prio);
+ } else {
+ if ((prio <= 0) || (prio >= MAX_USER_RT_PRIO))
+ prio = default_prio;
+
+ if (name != NULL)
+ printk(KERN_INFO "Using priority %d for 'softirq-%s'\n",
+ prio, name);
+ }
+ return prio;
+}
+
+/*
+ * Store the pointer to the arguments in a global var, and store the
+ * default prio globally
+ */
+static int __init softirq_prio_map_setup(char *str)
+{
+ if (!str) /* sanity check */
+ return 1;
+
+ cmdline = str; /* store it for later use */
+ default_prio = get_softirq_prio(NULL);
+
+ printk(KERN_INFO "Default softirq priority: %d\n", default_prio);
+
+ return 1;
+}
+
+/*
+ * The commandline looks like this:
+ * sirq_pmap=block/0:90,sched/0:75,50
+ * The first field without the ':' is used as the default for all
+ * soft-irq-threads. The priorities are only set on creation of the
+ * softirq threads. Unknown or redundant fields are ignored.
+ * The names have to match the softirq_names[] table without 'softirq-' prefix
+ * to keep the cmd-line short.
+ */
+__setup("sirq_pmap=", softirq_prio_map_setup);
--
^ permalink raw reply [flat|nested] 4+ messages in thread