From: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> Subject: mm/sparse: abstract sparse buffer allocations Patch series "sparse_init rewrite", v6. In sparse_init() we allocate two large buffers to temporary hold usemap and memmap for the whole machine. However, we can avoid doing that if we changed sparse_init() to operated on per-node bases instead of doing it on the whole machine beforehand. As shown by Baoquan http://lkml.kernel.org/r/20180628062857.29658-1-bhe@xxxxxxxxxx The buffers are large enough to cause machine stop to boot on small memory systems. Another benefit of these changes is that they also obsolete CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER. This patch (of 5): When struct pages are allocated for sparse-vmemmap VA layout, we first try to allocate one large buffer, and than if that fails allocate struct pages for each section as we go. The code that allocates buffer is uses global variables and is spread across several call sites. Cleanup the code by introducing three functions to handle the global buffer: sparse_buffer_init() initialize the buffer sparse_buffer_fini() free the remaining part of the buffer sparse_buffer_alloc() alloc from the buffer, and if buffer is empty return NULL Define these functions in sparse.c instead of sparse-vmemmap.c because later we will use them for non-vmemmap sparse allocations as well. [akpm@xxxxxxxxxxxxxxxxxxxx: use PTR_ALIGN()] [akpm@xxxxxxxxxxxxxxxxxxxx: s/BUG_ON/WARN_ON/] Link: http://lkml.kernel.org/r/20180712203730.8703-2-pasha.tatashin@xxxxxxxxxx Signed-off-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx> Tested-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> [powerpc] Reviewed-by: Oscar Salvador <osalvador@xxxxxxx> Tested-by: Oscar Salvador <osalvador@xxxxxxx> Cc: Pasha Tatashin <Pavel.Tatashin@xxxxxxxxxxxxx> Cc: Steven Sistare <steven.sistare@xxxxxxxxxx> Cc: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx> Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Jan Kara <jack@xxxxxxx> Cc: Jérôme Glisse <jglisse@xxxxxxxxxx> Cc: Souptick Joarder <jrdr.linux@xxxxxxxxx> Cc: Baoquan He <bhe@xxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: Wei Yang <richard.weiyang@xxxxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Abdul Haleem <abdhalee@xxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/mm.h | 4 +++ mm/sparse-vmemmap.c | 40 +++++-------------------------------- mm/sparse.c | 45 +++++++++++++++++++++++++++++++++++++++++- 3 files changed, 54 insertions(+), 35 deletions(-) --- a/include/linux/mm.h~mm-sparse-abstract-sparse-buffer-allocations +++ a/include/linux/mm.h @@ -2671,6 +2671,10 @@ void sparse_mem_maps_populate_node(struc unsigned long map_count, int nodeid); +unsigned long __init section_map_size(void); +void sparse_buffer_init(unsigned long size, int nid); +void sparse_buffer_fini(void); +void *sparse_buffer_alloc(unsigned long size); struct page *sparse_mem_map_populate(unsigned long pnum, int nid, struct vmem_altmap *altmap); pgd_t *vmemmap_pgd_populate(unsigned long addr, int node); --- a/mm/sparse.c~mm-sparse-abstract-sparse-buffer-allocations +++ a/mm/sparse.c @@ -400,7 +400,14 @@ static void __init sparse_early_usemaps_ } } -#ifndef CONFIG_SPARSEMEM_VMEMMAP +#ifdef CONFIG_SPARSEMEM_VMEMMAP +unsigned long __init section_map_size(void) + +{ + return ALIGN(sizeof(struct page) * PAGES_PER_SECTION, PMD_SIZE); +} + +#else struct page __init *sparse_mem_map_populate(unsigned long pnum, int nid, struct vmem_altmap *altmap) { @@ -457,6 +464,42 @@ void __init sparse_mem_maps_populate_nod } #endif /* !CONFIG_SPARSEMEM_VMEMMAP */ +static void *sparsemap_buf __meminitdata; +static void *sparsemap_buf_end __meminitdata; + +void __init sparse_buffer_init(unsigned long size, int nid) +{ + WARN_ON(sparsemap_buf); /* forgot to call sparse_buffer_fini()? */ + sparsemap_buf = + memblock_virt_alloc_try_nid_raw(size, PAGE_SIZE, + __pa(MAX_DMA_ADDRESS), + BOOTMEM_ALLOC_ACCESSIBLE, nid); + sparsemap_buf_end = sparsemap_buf + size; +} + +void __init sparse_buffer_fini(void) +{ + unsigned long size = sparsemap_buf_end - sparsemap_buf; + + if (sparsemap_buf && size > 0) + memblock_free_early(__pa(sparsemap_buf), size); + sparsemap_buf = NULL; +} + +void * __meminit sparse_buffer_alloc(unsigned long size) +{ + void *ptr = NULL; + + if (sparsemap_buf) { + ptr = PTR_ALIGN(sparsemap_buf, size); + if (ptr + size > sparsemap_buf_end) + ptr = NULL; + else + sparsemap_buf = ptr + size; + } + return ptr; +} + #ifdef CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER static void __init sparse_early_mem_maps_alloc_node(void *data, unsigned long pnum_begin, --- a/mm/sparse-vmemmap.c~mm-sparse-abstract-sparse-buffer-allocations +++ a/mm/sparse-vmemmap.c @@ -43,12 +43,9 @@ static void * __ref __earlyonly_bootmem_ unsigned long goal) { return memblock_virt_alloc_try_nid_raw(size, align, goal, - BOOTMEM_ALLOC_ACCESSIBLE, node); + BOOTMEM_ALLOC_ACCESSIBLE, node); } -static void *vmemmap_buf; -static void *vmemmap_buf_end; - void * __meminit vmemmap_alloc_block(unsigned long size, int node) { /* If the main allocator is up use that, fallback to bootmem. */ @@ -76,18 +73,10 @@ void * __meminit vmemmap_alloc_block(uns /* need to make sure size is all the same during early stage */ void * __meminit vmemmap_alloc_block_buf(unsigned long size, int node) { - void *ptr; - - if (!vmemmap_buf) - return vmemmap_alloc_block(size, node); - - /* take the from buf */ - ptr = (void *)ALIGN((unsigned long)vmemmap_buf, size); - if (ptr + size > vmemmap_buf_end) - return vmemmap_alloc_block(size, node); - - vmemmap_buf = ptr + size; + void *ptr = sparse_buffer_alloc(size); + if (!ptr) + ptr = vmemmap_alloc_block(size, node); return ptr; } @@ -279,19 +268,9 @@ void __init sparse_mem_maps_populate_nod unsigned long map_count, int nodeid) { unsigned long pnum; - unsigned long size = sizeof(struct page) * PAGES_PER_SECTION; - void *vmemmap_buf_start; int nr_consumed_maps = 0; - size = ALIGN(size, PMD_SIZE); - vmemmap_buf_start = __earlyonly_bootmem_alloc(nodeid, size * map_count, - PMD_SIZE, __pa(MAX_DMA_ADDRESS)); - - if (vmemmap_buf_start) { - vmemmap_buf = vmemmap_buf_start; - vmemmap_buf_end = vmemmap_buf_start + size * map_count; - } - + sparse_buffer_init(section_map_size() * map_count, nodeid); for (pnum = pnum_begin; pnum < pnum_end; pnum++) { if (!present_section_nr(pnum)) continue; @@ -303,12 +282,5 @@ void __init sparse_mem_maps_populate_nod pr_err("%s: sparsemem memory map backing failed some memory will not be available\n", __func__); } - - if (vmemmap_buf_start) { - /* need to free left buf */ - memblock_free_early(__pa(vmemmap_buf), - vmemmap_buf_end - vmemmap_buf); - vmemmap_buf = NULL; - vmemmap_buf_end = NULL; - } + sparse_buffer_fini(); } _
