On Fri, 13 Oct 2017 13:32:12 -0400 Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> wrote: > vmemmap_alloc_block() will no longer zero the block, so zero memory > at its call sites for everything except struct pages. Struct page memory > is zero'd by struct page initialization. > > Replace allocators in sprase-vmemmap to use the non-zeroing version. So, > we will get the performance improvement by zeroing the memory in parallel > when struct pages are zeroed. > > Add struct page zeroing as a part of initialization of other fields in > __init_single_page(). > > This single thread performance collected on: Intel(R) Xeon(R) CPU E7-8895 > v3 @ 2.60GHz with 1T of memory (268400646 pages in 8 nodes): > > BASE FIX > sparse_init 11.244671836s 0.007199623s > zone_sizes_init 4.879775891s 8.355182299s > -------------------------- > Total 16.124447727s 8.362381922s > > sparse_init is where memory for struct pages is zeroed, and the zeroing > part is moved later in this patch into __init_single_page(), which is > called from zone_sizes_init(). x86_64 allmodconfig: WARNING: vmlinux.o(.text+0x29d099): Section mismatch in reference from the function T.1331() to the function .meminit.text:vmemmap_alloc_block() The function T.1331() references the function __meminit vmemmap_alloc_block(). This is often because T.1331 lacks a __meminit annotation or the annotation of vmemmap_alloc_block is wrong. >From a quick scan it's unclear to me why this is happening. Maybe gcc-4.4.4 decided to create an out-of-line version of vmemmap_alloc_block_zero() for some reason. Anyway. I see no reason to publish vmemmap_alloc_block_zero() to the whole world when it's only used in sparse-vmemmap.c. The below fixes the section mismatch: --- a/include/linux/mm.h~mm-stop-zeroing-memory-during-allocation-in-vmemmap-fix +++ a/include/linux/mm.h @@ -2529,17 +2529,6 @@ static inline void *vmemmap_alloc_block_ return __vmemmap_alloc_block_buf(size, node, NULL); } -static inline void *vmemmap_alloc_block_zero(unsigned long size, int node) -{ - void *p = vmemmap_alloc_block(size, node); - - if (!p) - return NULL; - memset(p, 0, size); - - return p; -} - void vmemmap_verify(pte_t *, int, unsigned long, unsigned long); int vmemmap_populate_basepages(unsigned long start, unsigned long end, int node); --- a/mm/sparse-vmemmap.c~mm-stop-zeroing-memory-during-allocation-in-vmemmap-fix +++ a/mm/sparse-vmemmap.c @@ -178,6 +178,17 @@ pte_t * __meminit vmemmap_pte_populate(p return pte; } +static void * __meminit vmemmap_alloc_block_zero(unsigned long size, int node) +{ + void *p = vmemmap_alloc_block(size, node); + + if (!p) + return NULL; + memset(p, 0, size); + + return p; +} + pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node) { pmd_t *pmd = pmd_offset(pud, addr); _ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>