From 76ebd0548df6ee48586e9b80d8fc2f58aa5fb51c Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sat, 9 Feb 2008 23:24:09 +0100 Subject: [PATCH] x86: introduce page pool in cpa DEBUG_PAGEALLOC was not possible on 64-bit due to its early-bootup hardcoded reliance on PSE pages, and the unrobustness of the runtime splitup of large pages. The splitup ended in recursive calls to alloc_pages() when a page for a pte split was requested. Avoid the recursion with a preallocated page pool, which is used to split up large mappings and gets refilled in the return path of kernel_map_pages after the split has been done. The size of the page pool is adjusted to the available memory. This part just implements the page pool and the initialization w/o using it yet. Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar --- arch/x86/mm/init_32.c | 2 + arch/x86/mm/init_64.c | 2 + arch/x86/mm/pageattr.c | 82 +++++++++++++++++++++++++++++++++++- include/asm-x86/cacheflush.h | 2 + 4 files changed, 87 insertions(+), 1 deletion(-) diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c index 54aba3cf9e..8106bba41e 100644 --- a/arch/x86/mm/init_32.c +++ b/arch/x86/mm/init_32.c @@ -664,6 +664,8 @@ void __init mem_init(void) if (boot_cpu_data.wp_works_ok < 0) test_wp_bit(); + cpa_init(); + /* * Subtle. SMP is doing it's boot stuff late (because it has to * fork idle threads) - but it also needs low mappings for the diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 620d2b6b6b..b59fc23815 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -528,6 +528,8 @@ void __init mem_init(void) reservedpages << (PAGE_SHIFT-10), datasize >> 10, initsize >> 10); + + cpa_init(); } void free_init_pages(char *what, unsigned long begin, unsigned long end) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index eb2a54415a..831462c3bc 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include @@ -336,6 +337,77 @@ out_unlock: return do_split; } +static LIST_HEAD(page_pool); +static unsigned long pool_size, pool_pages, pool_low; +static unsigned long pool_used, pool_failed, pool_refill; + +static void cpa_fill_pool(void) +{ + struct page *p; + gfp_t gfp = GFP_KERNEL; + + /* Do not allocate from interrupt context */ + if (in_irq() || irqs_disabled()) + return; + /* + * Check unlocked. I does not matter when we have one more + * page in the pool. The bit lock avoids recursive pool + * allocations: + */ + if (pool_pages >= pool_size || test_and_set_bit_lock(0, &pool_refill)) + return; + +#ifdef CONFIG_DEBUG_PAGEALLOC + /* + * We could do: + * gfp = in_atomic() ? GFP_ATOMIC : GFP_KERNEL; + * but this fails on !PREEMPT kernels + */ + gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN; +#endif + + while (pool_pages < pool_size) { + p = alloc_pages(gfp, 0); + if (!p) { + pool_failed++; + break; + } + spin_lock_irq(&pgd_lock); + list_add(&p->lru, &page_pool); + pool_pages++; + spin_unlock_irq(&pgd_lock); + } + clear_bit_unlock(0, &pool_refill); +} + +#define SHIFT_MB (20 - PAGE_SHIFT) +#define ROUND_MB_GB ((1 << 10) - 1) +#define SHIFT_MB_GB 10 +#define POOL_PAGES_PER_GB 16 + +void __init cpa_init(void) +{ + struct sysinfo si; + unsigned long gb; + + si_meminfo(&si); + /* + * Calculate the number of pool pages: + * + * Convert totalram (nr of pages) to MiB and round to the next + * GiB. Shift MiB to Gib and multiply the result by + * POOL_PAGES_PER_GB: + */ + gb = ((si.totalram >> SHIFT_MB) + ROUND_MB_GB) >> SHIFT_MB_GB; + pool_size = POOL_PAGES_PER_GB * gb; + pool_low = pool_size; + + cpa_fill_pool(); + printk(KERN_DEBUG + "CPA: page pool initialized %lu of %lu pages preallocated\n", + pool_pages, pool_size); +} + static int split_large_page(pte_t *kpte, unsigned long address) { unsigned long flags, pfn, pfninc = 1; @@ -600,7 +672,7 @@ static int change_page_attr_set_clr(unsigned long addr, int numpages, * Check whether we really changed something: */ if (!cpa.flushtlb) - return ret; + goto out; /* * No need to flush, when we did not set any of the caching @@ -619,6 +691,8 @@ static int change_page_attr_set_clr(unsigned long addr, int numpages, else cpa_flush_all(cache); +out: + cpa_fill_pool(); return ret; } @@ -772,6 +846,12 @@ void kernel_map_pages(struct page *page, int numpages, int enable) * but that can deadlock->flush only current cpu: */ __flush_tlb_all(); + + /* + * Try to refill the page pool here. We can do this only after + * the tlb flush. + */ + cpa_fill_pool(); } #endif diff --git a/include/asm-x86/cacheflush.h b/include/asm-x86/cacheflush.h index 8dd8c5e3cc..6a22212b4b 100644 --- a/include/asm-x86/cacheflush.h +++ b/include/asm-x86/cacheflush.h @@ -44,6 +44,8 @@ int set_memory_np(unsigned long addr, int numpages); void clflush_cache_range(void *addr, unsigned int size); +void cpa_init(void); + #ifdef CONFIG_DEBUG_RODATA void mark_rodata_ro(void); #endif -- 2.39.5