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powerpc/64: Use array of paca pointers and allocate pacas individually

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Change the paca array into an array of pointers to pacas. Allocate
pacas individually.

This allows flexibility in where the PACAs are allocated. Future work
will allocate them node-local. Platforms that don't have address limits
on PACAs would be able to defer PACA allocations until later in boot
rather than allocate all possible ones up-front then freeing unused.

This is slightly more overhead (one additional indirection) for cross
CPU paca references, but those aren't too common.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Nicholas Piggin
2018-02-14 01:08:12 +10:00
committed by Michael Ellerman
parent 8e0b634b13
commit d2e60075a3
26 changed files with 141 additions and 105 deletions
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66
arch/powerpc/kernel/paca.c
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@@ -161,8 +161,8 @@ static void __init allocate_slb_shadows(int nr_cpus, int limit) { }
* processors. The processor VPD array needs one entry per physical
* processor (not thread).
*/
struct paca_struct *paca;
EXPORT_SYMBOL(paca);
struct paca_struct **paca_ptrs __read_mostly;
EXPORT_SYMBOL(paca_ptrs);
void __init initialise_paca(struct paca_struct *new_paca, int cpu)
{
@@ -213,11 +213,13 @@ void setup_paca(struct paca_struct *new_paca)
}
static int __initdata paca_size;
static int __initdata paca_nr_cpu_ids;
static int __initdata paca_ptrs_size;
void __init allocate_pacas(void)
{
u64 limit;
unsigned long size = 0;
int cpu;
#ifdef CONFIG_PPC_BOOK3S_64
@@ -230,13 +232,27 @@ void __init allocate_pacas(void)
limit = ppc64_rma_size;
#endif
paca_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpu_ids);
paca_nr_cpu_ids = nr_cpu_ids;
paca = __va(memblock_alloc_base(paca_size, PAGE_SIZE, limit));
memset(paca, 0, paca_size);
paca_ptrs_size = sizeof(struct paca_struct *) * nr_cpu_ids;
paca_ptrs = __va(memblock_alloc_base(paca_ptrs_size, 0, limit));
memset(paca_ptrs, 0, paca_ptrs_size);
printk(KERN_DEBUG "Allocated %u bytes for %u pacas at %p\n",
paca_size, nr_cpu_ids, paca);
size += paca_ptrs_size;
for (cpu = 0; cpu < nr_cpu_ids; cpu++) {
unsigned long pa;
pa = memblock_alloc_base(sizeof(struct paca_struct),
L1_CACHE_BYTES, limit);
paca_ptrs[cpu] = __va(pa);
memset(paca_ptrs[cpu], 0, sizeof(struct paca_struct));
size += sizeof(struct paca_struct);
}
printk(KERN_DEBUG "Allocated %lu bytes for %u pacas\n",
size, nr_cpu_ids);
allocate_lppacas(nr_cpu_ids, limit);
@@ -244,26 +260,38 @@ void __init allocate_pacas(void)
/* Can't use for_each_*_cpu, as they aren't functional yet */
for (cpu = 0; cpu < nr_cpu_ids; cpu++)
initialise_paca(&paca[cpu], cpu);
initialise_paca(paca_ptrs[cpu], cpu);
}
void __init free_unused_pacas(void)
{
int new_size;
unsigned long size = 0;
int new_ptrs_size;
int cpu;
new_size = PAGE_ALIGN(sizeof(struct paca_struct) * nr_cpu_ids);
for (cpu = 0; cpu < paca_nr_cpu_ids; cpu++) {
if (!cpu_possible(cpu)) {
unsigned long pa = __pa(paca_ptrs[cpu]);
memblock_free(pa, sizeof(struct paca_struct));
paca_ptrs[cpu] = NULL;
size += sizeof(struct paca_struct);
}
}
if (new_size >= paca_size)
return;
new_ptrs_size = sizeof(struct paca_struct *) * nr_cpu_ids;
if (new_ptrs_size < paca_ptrs_size) {
memblock_free(__pa(paca_ptrs) + new_ptrs_size,
paca_ptrs_size - new_ptrs_size);
size += paca_ptrs_size - new_ptrs_size;
}
memblock_free(__pa(paca) + new_size, paca_size - new_size);
printk(KERN_DEBUG "Freed %u bytes for unused pacas\n",
paca_size - new_size);
paca_size = new_size;
if (size)
printk(KERN_DEBUG "Freed %lu bytes for unused pacas\n", size);
free_lppacas();
paca_nr_cpu_ids = nr_cpu_ids;
paca_ptrs_size = new_ptrs_size;
}
void copy_mm_to_paca(struct mm_struct *mm)