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percpu: generalize first chunk allocator selection

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Now that all first chunk allocators are in mm/percpu.c, it makes sense
to make generalize percpu_alloc kernel parameter.  Define PCPU_FC_*
and set pcpu_chosen_fc using early_param() in mm/percpu.c.  Arch code
can use the set value to determine which first chunk allocator to use.

Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Tejun Heo 2009-08-14 15:00:50 +09:00
parent 08fc458061
commit f58dc01ba2
4 changed files with 56 additions and 23 deletions
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11
Documentation/kernel-parameters.txt
View File

@ -1919,11 +1919,12 @@ and is between 256 and 4096 characters. It is defined in the file
Format: { 0 | 1 }
See arch/parisc/kernel/pdc_chassis.c
percpu_alloc= [X86] Select which percpu first chunk allocator to use.
Allowed values are one of "lpage", "embed" and "page".
See comments in arch/x86/kernel/setup_percpu.c for
details on each allocator. This parameter is primarily
for debugging and performance comparison.
percpu_alloc= Select which percpu first chunk allocator to use.
Currently supported values are "embed", "page" and
"lpage". Archs may support subset or none of the
selections. See comments in mm/percpu.c for details
on each allocator. This parameter is primarily for
debugging and performance comparison.
pf. [PARIDE]
See Documentation/blockdev/paride.txt.

24
arch/x86/kernel/setup_percpu.c
View File

@ -267,16 +267,6 @@ static ssize_t __init setup_pcpu_page(size_t static_size)
pcpup_populate_pte);
}
/* for explicit first chunk allocator selection */
static char pcpu_chosen_alloc[16] __initdata;
static int __init percpu_alloc_setup(char *str)
{
strncpy(pcpu_chosen_alloc, str, sizeof(pcpu_chosen_alloc) - 1);
return 0;
}
early_param("percpu_alloc", percpu_alloc_setup);
static inline void setup_percpu_segment(int cpu)
{
#ifdef CONFIG_X86_32
@ -307,19 +297,17 @@ void __init setup_per_cpu_areas(void)
* each allocator for details.
*/
ret = -EINVAL;
if (strlen(pcpu_chosen_alloc)) {
if (strcmp(pcpu_chosen_alloc, "page")) {
if (!strcmp(pcpu_chosen_alloc, "lpage"))
if (pcpu_chosen_fc != PCPU_FC_AUTO) {
if (pcpu_chosen_fc != PCPU_FC_PAGE) {
if (pcpu_chosen_fc == PCPU_FC_LPAGE)
ret = setup_pcpu_lpage(static_size, true);
else if (!strcmp(pcpu_chosen_alloc, "embed"))
ret = setup_pcpu_embed(static_size, true);
else
pr_warning("PERCPU: unknown allocator %s "
"specified\n", pcpu_chosen_alloc);
ret = setup_pcpu_embed(static_size, true);
if (ret < 0)
pr_warning("PERCPU: %s allocator failed (%zd), "
"falling back to page size\n",
pcpu_chosen_alloc, ret);
pcpu_fc_names[pcpu_chosen_fc], ret);
}
} else {
ret = setup_pcpu_lpage(static_size, false);

12
include/linux/percpu.h
View File

@ -59,6 +59,18 @@
extern void *pcpu_base_addr;
extern const int *pcpu_unit_map;
enum pcpu_fc {
PCPU_FC_AUTO,
PCPU_FC_EMBED,
PCPU_FC_PAGE,
PCPU_FC_LPAGE,
PCPU_FC_NR,
};
extern const char *pcpu_fc_names[PCPU_FC_NR];
extern enum pcpu_fc pcpu_chosen_fc;
typedef void * (*pcpu_fc_alloc_fn_t)(unsigned int cpu, size_t size);
typedef void (*pcpu_fc_free_fn_t)(void *ptr, size_t size);
typedef void (*pcpu_fc_populate_pte_fn_t)(unsigned long addr);

32
mm/percpu.c
View File

@ -1414,6 +1414,38 @@ size_t __init pcpu_setup_first_chunk(size_t static_size, size_t reserved_size,
return pcpu_unit_size;
}
const char *pcpu_fc_names[PCPU_FC_NR] __initdata = {
[PCPU_FC_AUTO] = "auto",
[PCPU_FC_EMBED] = "embed",
[PCPU_FC_PAGE] = "page",
[PCPU_FC_LPAGE] = "lpage",
};
enum pcpu_fc pcpu_chosen_fc __initdata = PCPU_FC_AUTO;
static int __init percpu_alloc_setup(char *str)
{
if (0)
/* nada */;
#ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
else if (!strcmp(str, "embed"))
pcpu_chosen_fc = PCPU_FC_EMBED;
#endif
#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
else if (!strcmp(str, "page"))
pcpu_chosen_fc = PCPU_FC_PAGE;
#endif
#ifdef CONFIG_NEED_PER_CPU_LPAGE_FIRST_CHUNK
else if (!strcmp(str, "lpage"))
pcpu_chosen_fc = PCPU_FC_LPAGE;
#endif
else
pr_warning("PERCPU: unknown allocator %s specified\n", str);
return 0;
}
early_param("percpu_alloc", percpu_alloc_setup);
static inline size_t pcpu_calc_fc_sizes(size_t static_size,
size_t reserved_size,
ssize_t *dyn_sizep)