Messages in this thread | | | Subject | Re: [PATCH v2 2/3] arm64: Support page mapping percpu first chunk allocator | From | Kefeng Wang <> | Date | Mon, 2 Aug 2021 10:47:04 +0800 |
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On 2021/8/1 23:53, Catalin Marinas wrote: > On Tue, Jul 20, 2021 at 10:51:04AM +0800, Kefeng Wang wrote: >> Percpu embedded first chunk allocator is the firstly option, but it >> could fails on ARM64, eg, >> "percpu: max_distance=0x5fcfdc640000 too large for vmalloc space 0x781fefff0000" >> "percpu: max_distance=0x600000540000 too large for vmalloc space 0x7dffb7ff0000" >> "percpu: max_distance=0x5fff9adb0000 too large for vmalloc space 0x5dffb7ff0000" >> >> then we could meet "WARNING: CPU: 15 PID: 461 at vmalloc.c:3087 pcpu_get_vm_areas+0x488/0x838", >> even the system could not boot successfully. >> >> Let's implement page mapping percpu first chunk allocator as a fallback >> to the embedding allocator to increase the robustness of the system. > It looks like x86, powerpc and sparc implement their own > setup_per_cpu_areas(). I had a quick look on finding some commonalities > but I think it's a lot more hassle to make a generic version out of them > (powerpc looks the simplest though). I think we could add a generic > variant with the arm64 support and later migrate other architectures to > it if possible. Ok, let's do it later, I could try to make some cleanup after the patchset is merged ;) > The patch looks ok to me otherwise but I'd need an ack from Greg as it > touches drivers/.
the arch_numa is only used ARM64 and riscv, the NEED_PER_CPU_PAGE_FIRST_CHUNK
is not enabled on RISCV, so it's no bad effect.
> > BTW, do we need something similar for the non-NUMA > setup_per_cpu_areas()? I can see this patch only enables > NEED_PER_CPU_PAGE_FIRST_CHUNK if NUMA. > > Leaving the rest of the patch below for Greg. > >> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> >> --- >> arch/arm64/Kconfig | 4 ++ >> drivers/base/arch_numa.c | 82 +++++++++++++++++++++++++++++++++++----- >> 2 files changed, 76 insertions(+), 10 deletions(-) >> >> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig >> index b5b13a932561..eacb5873ded1 100644 >> --- a/arch/arm64/Kconfig >> +++ b/arch/arm64/Kconfig >> @@ -1045,6 +1045,10 @@ config NEED_PER_CPU_EMBED_FIRST_CHUNK >> def_bool y >> depends on NUMA >> >> +config NEED_PER_CPU_PAGE_FIRST_CHUNK >> + def_bool y >> + depends on NUMA >> + >> source "kernel/Kconfig.hz" >> >> config ARCH_SPARSEMEM_ENABLE >> diff --git a/drivers/base/arch_numa.c b/drivers/base/arch_numa.c >> index 4cc4e117727d..563b2013b75a 100644 >> --- a/drivers/base/arch_numa.c >> +++ b/drivers/base/arch_numa.c >> @@ -14,6 +14,7 @@ >> #include <linux/of.h> >> >> #include <asm/sections.h> >> +#include <asm/pgalloc.h> >> >> struct pglist_data *node_data[MAX_NUMNODES] __read_mostly; >> EXPORT_SYMBOL(node_data); >> @@ -168,22 +169,83 @@ static void __init pcpu_fc_free(void *ptr, size_t size) >> memblock_free_early(__pa(ptr), size); >> } >> >> +#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK >> +static void __init pcpu_populate_pte(unsigned long addr) >> +{ >> + pgd_t *pgd = pgd_offset_k(addr); >> + p4d_t *p4d; >> + pud_t *pud; >> + pmd_t *pmd; >> + >> + p4d = p4d_offset(pgd, addr); >> + if (p4d_none(*p4d)) { >> + pud_t *new; >> + >> + new = memblock_alloc(PAGE_SIZE, PAGE_SIZE); >> + if (!new) >> + goto err_alloc; >> + p4d_populate(&init_mm, p4d, new); >> + } >> + >> + pud = pud_offset(p4d, addr); >> + if (pud_none(*pud)) { >> + pmd_t *new; >> + >> + new = memblock_alloc(PAGE_SIZE, PAGE_SIZE); >> + if (!new) >> + goto err_alloc; >> + pud_populate(&init_mm, pud, new); >> + } >> + >> + pmd = pmd_offset(pud, addr); >> + if (!pmd_present(*pmd)) { >> + pte_t *new; >> + >> + new = memblock_alloc(PAGE_SIZE, PAGE_SIZE); >> + if (!new) >> + goto err_alloc; >> + pmd_populate_kernel(&init_mm, pmd, new); >> + } >> + >> + return; >> + >> +err_alloc: >> + panic("%s: Failed to allocate %lu bytes align=%lx from=%lx\n", >> + __func__, PAGE_SIZE, PAGE_SIZE, PAGE_SIZE); >> +} >> +#endif >> + >> void __init setup_per_cpu_areas(void) >> { >> unsigned long delta; >> unsigned int cpu; >> - int rc; >> + int rc = -EINVAL; >> + >> + if (pcpu_chosen_fc != PCPU_FC_PAGE) { >> + /* >> + * Always reserve area for module percpu variables. That's >> + * what the legacy allocator did. >> + */ >> + rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE, >> + PERCPU_DYNAMIC_RESERVE, PAGE_SIZE, >> + pcpu_cpu_distance, >> + pcpu_fc_alloc, pcpu_fc_free); >> +#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK >> + if (rc < 0) >> + pr_warn("PERCPU: %s allocator failed (%d), falling back to page size\n", >> + pcpu_fc_names[pcpu_chosen_fc], rc); >> +#endif >> + } >> >> - /* >> - * Always reserve area for module percpu variables. That's >> - * what the legacy allocator did. >> - */ >> - rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE, >> - PERCPU_DYNAMIC_RESERVE, PAGE_SIZE, >> - pcpu_cpu_distance, >> - pcpu_fc_alloc, pcpu_fc_free); >> +#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK >> + if (rc < 0) >> + rc = pcpu_page_first_chunk(PERCPU_MODULE_RESERVE, >> + pcpu_fc_alloc, >> + pcpu_fc_free, >> + pcpu_populate_pte); >> +#endif >> if (rc < 0) >> - panic("Failed to initialize percpu areas."); >> + panic("Failed to initialize percpu areas (err=%d).", rc); >> >> delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start; >> for_each_possible_cpu(cpu) >> -- >> 2.26.2 > . >
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