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![Vlastimil Babka](/assets/img/avatar_default.png)
page_ext_init() can take long on large machines, so add a cond_resched() point after each section is processed. This will allow moving the init to a later point at boot without triggering lockup reports. Link: http://lkml.kernel.org/r/20170720134029.25268-3-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Yang Shi <yang.shi@linaro.org> Cc: Laura Abbott <labbott@redhat.com> Cc: Vinayak Menon <vinmenon@codeaurora.org> Cc: zhong jiang <zhongjiang@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
425 lines
11 KiB
C
425 lines
11 KiB
C
#include <linux/mm.h>
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#include <linux/mmzone.h>
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#include <linux/bootmem.h>
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#include <linux/page_ext.h>
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#include <linux/memory.h>
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#include <linux/vmalloc.h>
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#include <linux/kmemleak.h>
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#include <linux/page_owner.h>
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#include <linux/page_idle.h>
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/*
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* struct page extension
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*
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* This is the feature to manage memory for extended data per page.
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*
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* Until now, we must modify struct page itself to store extra data per page.
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* This requires rebuilding the kernel and it is really time consuming process.
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* And, sometimes, rebuild is impossible due to third party module dependency.
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* At last, enlarging struct page could cause un-wanted system behaviour change.
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*
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* This feature is intended to overcome above mentioned problems. This feature
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* allocates memory for extended data per page in certain place rather than
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* the struct page itself. This memory can be accessed by the accessor
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* functions provided by this code. During the boot process, it checks whether
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* allocation of huge chunk of memory is needed or not. If not, it avoids
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* allocating memory at all. With this advantage, we can include this feature
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* into the kernel in default and can avoid rebuild and solve related problems.
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*
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* To help these things to work well, there are two callbacks for clients. One
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* is the need callback which is mandatory if user wants to avoid useless
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* memory allocation at boot-time. The other is optional, init callback, which
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* is used to do proper initialization after memory is allocated.
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*
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* The need callback is used to decide whether extended memory allocation is
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* needed or not. Sometimes users want to deactivate some features in this
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* boot and extra memory would be unneccessary. In this case, to avoid
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* allocating huge chunk of memory, each clients represent their need of
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* extra memory through the need callback. If one of the need callbacks
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* returns true, it means that someone needs extra memory so that
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* page extension core should allocates memory for page extension. If
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* none of need callbacks return true, memory isn't needed at all in this boot
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* and page extension core can skip to allocate memory. As result,
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* none of memory is wasted.
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*
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* When need callback returns true, page_ext checks if there is a request for
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* extra memory through size in struct page_ext_operations. If it is non-zero,
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* extra space is allocated for each page_ext entry and offset is returned to
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* user through offset in struct page_ext_operations.
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*
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* The init callback is used to do proper initialization after page extension
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* is completely initialized. In sparse memory system, extra memory is
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* allocated some time later than memmap is allocated. In other words, lifetime
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* of memory for page extension isn't same with memmap for struct page.
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* Therefore, clients can't store extra data until page extension is
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* initialized, even if pages are allocated and used freely. This could
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* cause inadequate state of extra data per page, so, to prevent it, client
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* can utilize this callback to initialize the state of it correctly.
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*/
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static struct page_ext_operations *page_ext_ops[] = {
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&debug_guardpage_ops,
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#ifdef CONFIG_PAGE_OWNER
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&page_owner_ops,
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#endif
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#if defined(CONFIG_IDLE_PAGE_TRACKING) && !defined(CONFIG_64BIT)
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&page_idle_ops,
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#endif
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};
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static unsigned long total_usage;
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static unsigned long extra_mem;
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static bool __init invoke_need_callbacks(void)
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{
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int i;
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int entries = ARRAY_SIZE(page_ext_ops);
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bool need = false;
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for (i = 0; i < entries; i++) {
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if (page_ext_ops[i]->need && page_ext_ops[i]->need()) {
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page_ext_ops[i]->offset = sizeof(struct page_ext) +
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extra_mem;
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extra_mem += page_ext_ops[i]->size;
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need = true;
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}
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}
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return need;
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}
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static void __init invoke_init_callbacks(void)
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{
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int i;
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int entries = ARRAY_SIZE(page_ext_ops);
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for (i = 0; i < entries; i++) {
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if (page_ext_ops[i]->init)
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page_ext_ops[i]->init();
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}
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}
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static unsigned long get_entry_size(void)
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{
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return sizeof(struct page_ext) + extra_mem;
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}
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static inline struct page_ext *get_entry(void *base, unsigned long index)
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{
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return base + get_entry_size() * index;
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}
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#if !defined(CONFIG_SPARSEMEM)
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void __meminit pgdat_page_ext_init(struct pglist_data *pgdat)
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{
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pgdat->node_page_ext = NULL;
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}
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struct page_ext *lookup_page_ext(struct page *page)
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{
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unsigned long pfn = page_to_pfn(page);
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unsigned long index;
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struct page_ext *base;
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base = NODE_DATA(page_to_nid(page))->node_page_ext;
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#if defined(CONFIG_DEBUG_VM)
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/*
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* The sanity checks the page allocator does upon freeing a
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* page can reach here before the page_ext arrays are
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* allocated when feeding a range of pages to the allocator
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* for the first time during bootup or memory hotplug.
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*/
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if (unlikely(!base))
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return NULL;
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#endif
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index = pfn - round_down(node_start_pfn(page_to_nid(page)),
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MAX_ORDER_NR_PAGES);
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return get_entry(base, index);
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}
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static int __init alloc_node_page_ext(int nid)
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{
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struct page_ext *base;
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unsigned long table_size;
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unsigned long nr_pages;
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nr_pages = NODE_DATA(nid)->node_spanned_pages;
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if (!nr_pages)
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return 0;
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/*
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* Need extra space if node range is not aligned with
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* MAX_ORDER_NR_PAGES. When page allocator's buddy algorithm
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* checks buddy's status, range could be out of exact node range.
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*/
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if (!IS_ALIGNED(node_start_pfn(nid), MAX_ORDER_NR_PAGES) ||
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!IS_ALIGNED(node_end_pfn(nid), MAX_ORDER_NR_PAGES))
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nr_pages += MAX_ORDER_NR_PAGES;
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table_size = get_entry_size() * nr_pages;
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base = memblock_virt_alloc_try_nid_nopanic(
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table_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS),
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BOOTMEM_ALLOC_ACCESSIBLE, nid);
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if (!base)
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return -ENOMEM;
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NODE_DATA(nid)->node_page_ext = base;
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total_usage += table_size;
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return 0;
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}
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void __init page_ext_init_flatmem(void)
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{
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int nid, fail;
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if (!invoke_need_callbacks())
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return;
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for_each_online_node(nid) {
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fail = alloc_node_page_ext(nid);
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if (fail)
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goto fail;
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}
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pr_info("allocated %ld bytes of page_ext\n", total_usage);
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invoke_init_callbacks();
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return;
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fail:
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pr_crit("allocation of page_ext failed.\n");
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panic("Out of memory");
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}
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#else /* CONFIG_FLAT_NODE_MEM_MAP */
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struct page_ext *lookup_page_ext(struct page *page)
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{
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unsigned long pfn = page_to_pfn(page);
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struct mem_section *section = __pfn_to_section(pfn);
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#if defined(CONFIG_DEBUG_VM)
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/*
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* The sanity checks the page allocator does upon freeing a
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* page can reach here before the page_ext arrays are
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* allocated when feeding a range of pages to the allocator
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* for the first time during bootup or memory hotplug.
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*/
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if (!section->page_ext)
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return NULL;
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#endif
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return get_entry(section->page_ext, pfn);
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}
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static void *__meminit alloc_page_ext(size_t size, int nid)
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{
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gfp_t flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN;
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void *addr = NULL;
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addr = alloc_pages_exact_nid(nid, size, flags);
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if (addr) {
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kmemleak_alloc(addr, size, 1, flags);
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return addr;
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}
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addr = vzalloc_node(size, nid);
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return addr;
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}
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static int __meminit init_section_page_ext(unsigned long pfn, int nid)
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{
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struct mem_section *section;
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struct page_ext *base;
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unsigned long table_size;
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section = __pfn_to_section(pfn);
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if (section->page_ext)
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return 0;
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table_size = get_entry_size() * PAGES_PER_SECTION;
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base = alloc_page_ext(table_size, nid);
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/*
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* The value stored in section->page_ext is (base - pfn)
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* and it does not point to the memory block allocated above,
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* causing kmemleak false positives.
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*/
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kmemleak_not_leak(base);
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if (!base) {
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pr_err("page ext allocation failure\n");
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return -ENOMEM;
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}
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/*
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* The passed "pfn" may not be aligned to SECTION. For the calculation
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* we need to apply a mask.
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*/
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pfn &= PAGE_SECTION_MASK;
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section->page_ext = (void *)base - get_entry_size() * pfn;
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total_usage += table_size;
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return 0;
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}
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#ifdef CONFIG_MEMORY_HOTPLUG
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static void free_page_ext(void *addr)
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{
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if (is_vmalloc_addr(addr)) {
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vfree(addr);
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} else {
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struct page *page = virt_to_page(addr);
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size_t table_size;
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table_size = get_entry_size() * PAGES_PER_SECTION;
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BUG_ON(PageReserved(page));
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free_pages_exact(addr, table_size);
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}
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}
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static void __free_page_ext(unsigned long pfn)
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{
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struct mem_section *ms;
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struct page_ext *base;
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ms = __pfn_to_section(pfn);
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if (!ms || !ms->page_ext)
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return;
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base = get_entry(ms->page_ext, pfn);
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free_page_ext(base);
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ms->page_ext = NULL;
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}
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static int __meminit online_page_ext(unsigned long start_pfn,
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unsigned long nr_pages,
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int nid)
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{
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unsigned long start, end, pfn;
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int fail = 0;
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start = SECTION_ALIGN_DOWN(start_pfn);
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end = SECTION_ALIGN_UP(start_pfn + nr_pages);
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if (nid == -1) {
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/*
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* In this case, "nid" already exists and contains valid memory.
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* "start_pfn" passed to us is a pfn which is an arg for
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* online__pages(), and start_pfn should exist.
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*/
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nid = pfn_to_nid(start_pfn);
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VM_BUG_ON(!node_state(nid, N_ONLINE));
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}
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for (pfn = start; !fail && pfn < end; pfn += PAGES_PER_SECTION) {
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if (!pfn_present(pfn))
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continue;
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fail = init_section_page_ext(pfn, nid);
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}
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if (!fail)
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return 0;
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/* rollback */
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for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
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__free_page_ext(pfn);
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return -ENOMEM;
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}
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static int __meminit offline_page_ext(unsigned long start_pfn,
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unsigned long nr_pages, int nid)
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{
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unsigned long start, end, pfn;
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start = SECTION_ALIGN_DOWN(start_pfn);
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end = SECTION_ALIGN_UP(start_pfn + nr_pages);
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for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
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__free_page_ext(pfn);
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return 0;
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}
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static int __meminit page_ext_callback(struct notifier_block *self,
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unsigned long action, void *arg)
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{
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struct memory_notify *mn = arg;
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int ret = 0;
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switch (action) {
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case MEM_GOING_ONLINE:
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ret = online_page_ext(mn->start_pfn,
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mn->nr_pages, mn->status_change_nid);
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break;
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case MEM_OFFLINE:
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offline_page_ext(mn->start_pfn,
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mn->nr_pages, mn->status_change_nid);
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break;
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case MEM_CANCEL_ONLINE:
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offline_page_ext(mn->start_pfn,
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mn->nr_pages, mn->status_change_nid);
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break;
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case MEM_GOING_OFFLINE:
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break;
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case MEM_ONLINE:
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case MEM_CANCEL_OFFLINE:
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break;
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}
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return notifier_from_errno(ret);
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}
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#endif
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void __init page_ext_init(void)
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{
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unsigned long pfn;
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int nid;
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if (!invoke_need_callbacks())
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return;
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for_each_node_state(nid, N_MEMORY) {
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unsigned long start_pfn, end_pfn;
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start_pfn = node_start_pfn(nid);
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end_pfn = node_end_pfn(nid);
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/*
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* start_pfn and end_pfn may not be aligned to SECTION and the
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* page->flags of out of node pages are not initialized. So we
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* scan [start_pfn, the biggest section's pfn < end_pfn) here.
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*/
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for (pfn = start_pfn; pfn < end_pfn;
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pfn = ALIGN(pfn + 1, PAGES_PER_SECTION)) {
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if (!pfn_valid(pfn))
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continue;
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/*
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* Nodes's pfns can be overlapping.
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* We know some arch can have a nodes layout such as
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* -------------pfn-------------->
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* N0 | N1 | N2 | N0 | N1 | N2|....
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*
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* Take into account DEFERRED_STRUCT_PAGE_INIT.
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*/
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if (early_pfn_to_nid(pfn) != nid)
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continue;
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if (init_section_page_ext(pfn, nid))
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goto oom;
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cond_resched();
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}
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}
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hotplug_memory_notifier(page_ext_callback, 0);
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pr_info("allocated %ld bytes of page_ext\n", total_usage);
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invoke_init_callbacks();
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return;
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oom:
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panic("Out of memory");
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}
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void __meminit pgdat_page_ext_init(struct pglist_data *pgdat)
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{
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}
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#endif
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