On Fri, Sep 17, 2021 at 02:55:18PM +0800, Kefeng Wang wrote: > > On 2021/9/17 14:24, Greg KH wrote: > > On Fri, Sep 10, 2021 at 01:33:53PM +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. > > > > > > Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx> > > > Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> > > > --- > > > 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 077f2ec4eeb2..04cfe1b4e98b 100644 > > > --- a/arch/arm64/Kconfig > > > +++ b/arch/arm64/Kconfig > > > @@ -1042,6 +1042,10 @@ 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 > > Why is this a config option at all? > > The config is introduced from > > commit 08fc45806103e59a37418e84719b878f9bb32540 > Author: Tejun Heo <tj@xxxxxxxxxx> > Date: Fri Aug 14 15:00:49 2009 +0900 > > percpu: build first chunk allocators selectively > > There's no need to build unused first chunk allocators in. Define > CONFIG_NEED_PER_CPU_*_FIRST_CHUNK and let archs enable them > selectively. > > For now, there are three ARCHs support both PER_CPU_EMBED_FIRST_CHUNK > > and PER_CPU_PAGE_FIRST_CHUNK. > > arch/powerpc/Kconfig:config NEED_PER_CPU_PAGE_FIRST_CHUNK > arch/sparc/Kconfig:config NEED_PER_CPU_PAGE_FIRST_CHUNK > arch/x86/Kconfig:config NEED_PER_CPU_PAGE_FIRST_CHUNK > > and we have a cmdline to choose a alloctor. > > percpu_alloc= Select which percpu first chunk allocator to use. > Currently supported values are "embed" and "page". > 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. > > embed percpu first chunk allocator is the first choice, but it could fails > due to some > > memory layout(it does occurs on ARM64 too.), so page mapping percpu first > chunk > > allocator is as a fallback, that is what this patch does. > > > > > > + > > > source "kernel/Kconfig.hz" > > > config ARCH_SPARSEMEM_ENABLE > > > diff --git a/drivers/base/arch_numa.c b/drivers/base/arch_numa.c > > > index 46c503486e96..995dca9f3254 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 > > Ick, no #ifdef in .c files if at all possible please. > > The drivers/base/arch_numa.c is shared by RISCV/ARM64, so I add this config > to > > no need to build this part on RISCV. Ok, then you need to get reviews from the mm people as I know nothing about this at all, sorry. This file ended up in drivers/base/ for some reason to make it easier for others to use cross-arches, not that it had much to do with the driver core :( thanks, greg k-h
