Messages in this thread | | | From | Huacai Chen <> | Date | Tue, 5 Sep 2023 18:59:59 +0800 | Subject | Re: [PATCH 2/2] LoongArch: Use static defined zero page rather than allocated |
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Hi, Bibo,
On Tue, Sep 5, 2023 at 4:01 PM Bibo Mao <maobibo@loongson.cn> wrote: > > Like other popular architectures, zero page is defined in kernel > BSS code segment, rather than dynamically alloted page. It is > simpler. > > Signed-off-by: Bibo Mao <maobibo@loongson.cn> > --- > arch/loongarch/include/asm/mmzone.h | 2 -- > arch/loongarch/include/asm/pgtable.h | 6 ++---- > arch/loongarch/kernel/numa.c | 1 - > arch/loongarch/mm/init.c | 21 +-------------------- > 4 files changed, 3 insertions(+), 27 deletions(-) > > diff --git a/arch/loongarch/include/asm/mmzone.h b/arch/loongarch/include/asm/mmzone.h > index fe67d0b4b33d..2b9a90727e19 100644 > --- a/arch/loongarch/include/asm/mmzone.h > +++ b/arch/loongarch/include/asm/mmzone.h > @@ -13,6 +13,4 @@ extern struct pglist_data *node_data[]; > > #define NODE_DATA(nid) (node_data[(nid)]) > > -extern void setup_zero_pages(void); > - > #endif /* _ASM_MMZONE_H_ */ > diff --git a/arch/loongarch/include/asm/pgtable.h b/arch/loongarch/include/asm/pgtable.h > index 342c5f9c25d2..70bd57daf42a 100644 > --- a/arch/loongarch/include/asm/pgtable.h > +++ b/arch/loongarch/include/asm/pgtable.h > @@ -70,10 +70,8 @@ struct vm_area_struct; > * for zero-mapped memory areas etc.. > */ > > -extern unsigned long empty_zero_page; > - > -#define ZERO_PAGE(vaddr) \ > - (virt_to_page((void *)(empty_zero_page))) > +extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]; > +#define ZERO_PAGE(vaddr) ((void)(vaddr), virt_to_page(empty_zero_page)) Can we simply use virt_to_page(empty_zero_page) here? Only x86 does it like this now.
Huacai > > /* > * TLB refill handlers may also map the vmalloc area into xkvrange. > diff --git a/arch/loongarch/kernel/numa.c b/arch/loongarch/kernel/numa.c > index 708665895b47..6f464d49f0c2 100644 > --- a/arch/loongarch/kernel/numa.c > +++ b/arch/loongarch/kernel/numa.c > @@ -470,7 +470,6 @@ void __init mem_init(void) > { > high_memory = (void *) __va(get_num_physpages() << PAGE_SHIFT); > memblock_free_all(); > - setup_zero_pages(); /* This comes from node 0 */ > } > > int pcibus_to_node(struct pci_bus *bus) > diff --git a/arch/loongarch/mm/init.c b/arch/loongarch/mm/init.c > index 8ec668f97b00..628ebe42b519 100644 > --- a/arch/loongarch/mm/init.c > +++ b/arch/loongarch/mm/init.c > @@ -35,27 +35,9 @@ > #include <asm/pgalloc.h> > #include <asm/tlb.h> > > -unsigned long empty_zero_page; > +unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss; > EXPORT_SYMBOL(empty_zero_page); > > -void setup_zero_pages(void) > -{ > - unsigned int order, i; > - struct page *page; > - > - order = 0; > - > - empty_zero_page = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order); > - if (!empty_zero_page) > - panic("Oh boy, that early out of memory?"); > - > - page = virt_to_page((void *)empty_zero_page); > - split_page(page, order); > - for (i = 0; i < (1 << order); i++, page++) > - mark_page_reserved(page); > - > -} > - > void copy_user_highpage(struct page *to, struct page *from, > unsigned long vaddr, struct vm_area_struct *vma) > { > @@ -99,7 +81,6 @@ void __init mem_init(void) > high_memory = (void *) __va(max_low_pfn << PAGE_SHIFT); > > memblock_free_all(); > - setup_zero_pages(); /* Setup zeroed pages. */ > } > #endif /* !CONFIG_NUMA */ > > -- > 2.27.0 > >
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