89 lines
2.0 KiB
C
89 lines
2.0 KiB
C
/*
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* Quicklist support.
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*
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* Quicklists are light weight lists of pages that have a defined state
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* on alloc and free. Pages must be in the quicklist specific defined state
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* (zero by default) when the page is freed. It seems that the initial idea
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* for such lists first came from Dave Miller and then various other people
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* improved on it.
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*
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* Copyright (C) 2007 SGI,
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* Christoph Lameter <clameter@sgi.com>
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* Generalized, added support for multiple lists and
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* constructors / destructors.
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*/
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/mmzone.h>
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#include <linux/module.h>
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#include <linux/quicklist.h>
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DEFINE_PER_CPU(struct quicklist, quicklist)[CONFIG_NR_QUICK];
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#define FRACTION_OF_NODE_MEM 16
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static unsigned long max_pages(unsigned long min_pages)
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{
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unsigned long node_free_pages, max;
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node_free_pages = node_page_state(numa_node_id(),
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NR_FREE_PAGES);
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max = node_free_pages / FRACTION_OF_NODE_MEM;
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return max(max, min_pages);
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}
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static long min_pages_to_free(struct quicklist *q,
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unsigned long min_pages, long max_free)
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{
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long pages_to_free;
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pages_to_free = q->nr_pages - max_pages(min_pages);
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return min(pages_to_free, max_free);
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}
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/*
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* Trim down the number of pages in the quicklist
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*/
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void quicklist_trim(int nr, void (*dtor)(void *),
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unsigned long min_pages, unsigned long max_free)
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{
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long pages_to_free;
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struct quicklist *q;
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q = &get_cpu_var(quicklist)[nr];
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if (q->nr_pages > min_pages) {
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pages_to_free = min_pages_to_free(q, min_pages, max_free);
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while (pages_to_free > 0) {
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/*
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* We pass a gfp_t of 0 to quicklist_alloc here
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* because we will never call into the page allocator.
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*/
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void *p = quicklist_alloc(nr, 0, NULL);
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if (dtor)
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dtor(p);
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free_page((unsigned long)p);
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pages_to_free--;
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}
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}
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put_cpu_var(quicklist);
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}
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unsigned long quicklist_total_size(void)
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{
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unsigned long count = 0;
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int cpu;
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struct quicklist *ql, *q;
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for_each_online_cpu(cpu) {
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ql = per_cpu(quicklist, cpu);
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for (q = ql; q < ql + CONFIG_NR_QUICK; q++)
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count += q->nr_pages;
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}
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return count;
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}
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