diff options
| -rw-r--r-- | include/linux/quicklist.h | 94 | ||||
| -rw-r--r-- | mm/Kconfig | 5 | ||||
| -rw-r--r-- | mm/Makefile | 2 | ||||
| -rw-r--r-- | mm/quicklist.c | 88 |
4 files changed, 189 insertions, 0 deletions
diff --git a/include/linux/quicklist.h b/include/linux/quicklist.h new file mode 100644 index 0000000..9371c61 --- /dev/null +++ b/include/linux/quicklist.h @@ -0,0 +1,94 @@ +#ifndef LINUX_QUICKLIST_H +#define LINUX_QUICKLIST_H +/* + * Fast allocations and disposal of pages. Pages must be in the condition + * as needed after allocation when they are freed. Per cpu lists of pages + * are kept that only contain node local pages. + * + * (C) 2007, SGI. Christoph Lameter <clameter@sgi.com> + */ +#include <linux/kernel.h> +#include <linux/gfp.h> +#include <linux/percpu.h> + +#ifdef CONFIG_QUICKLIST + +struct quicklist { + void *page; + int nr_pages; +}; + +DECLARE_PER_CPU(struct quicklist, quicklist)[CONFIG_NR_QUICK]; + +/* + * The two key functions quicklist_alloc and quicklist_free are inline so + * that they may be custom compiled for the platform. + * Specifying a NULL ctor can remove constructor support. Specifying + * a constant quicklist allows the determination of the exact address + * in the per cpu area. + * + * The fast patch in quicklist_alloc touched only a per cpu cacheline and + * the first cacheline of the page itself. There is minmal overhead involved. + */ +static inline void *quicklist_alloc(int nr, gfp_t flags, void (*ctor)(void *)) +{ + struct quicklist *q; + void **p = NULL; + + q =&get_cpu_var(quicklist)[nr]; + p = q->page; + if (likely(p)) { + q->page = p[0]; + p[0] = NULL; + q->nr_pages--; + } + put_cpu_var(quicklist); + if (likely(p)) + return p; + + p = (void *)__get_free_page(flags | __GFP_ZERO); + if (ctor && p) + ctor(p); + return p; +} + +static inline void __quicklist_free(int nr, void (*dtor)(void *), void *p, + struct page *page) +{ + struct quicklist *q; + int nid = page_to_nid(page); + + if (unlikely(nid != numa_node_id())) { + if (dtor) + dtor(p); + __free_page(page); + return; + } + + q = &get_cpu_var(quicklist)[nr]; + *(void **)p = q->page; + q->page = p; + q->nr_pages++; + put_cpu_var(quicklist); +} + +static inline void quicklist_free(int nr, void (*dtor)(void *), void *pp) +{ + __quicklist_free(nr, dtor, pp, virt_to_page(pp)); +} + +static inline void quicklist_free_page(int nr, void (*dtor)(void *), + struct page *page) +{ + __quicklist_free(nr, dtor, page_address(page), page); +} + +void quicklist_trim(int nr, void (*dtor)(void *), + unsigned long min_pages, unsigned long max_free); + +unsigned long quicklist_total_size(void); + +#endif + +#endif /* LINUX_QUICKLIST_H */ + @@ -163,3 +163,8 @@ config ZONE_DMA_FLAG default "0" if !ZONE_DMA default "1" +config NR_QUICK + int + depends on QUICKLIST + default "1" + diff --git a/mm/Makefile b/mm/Makefile index 1887148..a9148ea 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -30,3 +30,5 @@ obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o obj-$(CONFIG_FS_XIP) += filemap_xip.o obj-$(CONFIG_MIGRATION) += migrate.o obj-$(CONFIG_SMP) += allocpercpu.o +obj-$(CONFIG_QUICKLIST) += quicklist.o + diff --git a/mm/quicklist.c b/mm/quicklist.c new file mode 100644 index 0000000..ae8189c --- /dev/null +++ b/mm/quicklist.c @@ -0,0 +1,88 @@ +/* + * Quicklist support. + * + * Quicklists are light weight lists of pages that have a defined state + * on alloc and free. Pages must be in the quicklist specific defined state + * (zero by default) when the page is freed. It seems that the initial idea + * for such lists first came from Dave Miller and then various other people + * improved on it. + * + * Copyright (C) 2007 SGI, + * Christoph Lameter <clameter@sgi.com> + * Generalized, added support for multiple lists and + * constructors / destructors. + */ +#include <linux/kernel.h> + +#include <linux/mm.h> +#include <linux/mmzone.h> +#include <linux/module.h> +#include <linux/quicklist.h> + +DEFINE_PER_CPU(struct quicklist, quicklist)[CONFIG_NR_QUICK]; + +#define FRACTION_OF_NODE_MEM 16 + +static unsigned long max_pages(unsigned long min_pages) +{ + unsigned long node_free_pages, max; + + node_free_pages = node_page_state(numa_node_id(), + NR_FREE_PAGES); + max = node_free_pages / FRACTION_OF_NODE_MEM; + return max(max, min_pages); +} + +static long min_pages_to_free(struct quicklist *q, + unsigned long min_pages, long max_free) +{ + long pages_to_free; + + pages_to_free = q->nr_pages - max_pages(min_pages); + + return min(pages_to_free, max_free); +} + +/* + * Trim down the number of pages in the quicklist + */ +void quicklist_trim(int nr, void (*dtor)(void *), + unsigned long min_pages, unsigned long max_free) +{ + long pages_to_free; + struct quicklist *q; + + q = &get_cpu_var(quicklist)[nr]; + if (q->nr_pages > min_pages) { + pages_to_free = min_pages_to_free(q, min_pages, max_free); + + while (pages_to_free > 0) { + /* + * We pass a gfp_t of 0 to quicklist_alloc here + * because we will never call into the page allocator. + */ + void *p = quicklist_alloc(nr, 0, NULL); + + if (dtor) + dtor(p); + free_page((unsigned long)p); + pages_to_free--; + } + } + put_cpu_var(quicklist); +} + +unsigned long quicklist_total_size(void) +{ + unsigned long count = 0; + int cpu; + struct quicklist *ql, *q; + + for_each_online_cpu(cpu) { + ql = per_cpu(quicklist, cpu); + for (q = ql; q < ql + CONFIG_NR_QUICK; q++) + count += q->nr_pages; + } + return count; +} + |