150 lines
4.1 KiB
C
150 lines
4.1 KiB
C
/*
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* linux/mm/allocpercpu.c
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*
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* Separated from slab.c August 11, 2006 Christoph Lameter
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*/
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#include <linux/mm.h>
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#include <linux/module.h>
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#ifndef cache_line_size
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#define cache_line_size() L1_CACHE_BYTES
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#endif
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/**
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* percpu_depopulate - depopulate per-cpu data for given cpu
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* @__pdata: per-cpu data to depopulate
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* @cpu: depopulate per-cpu data for this cpu
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*
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* Depopulating per-cpu data for a cpu going offline would be a typical
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* use case. You need to register a cpu hotplug handler for that purpose.
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*/
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static void percpu_depopulate(void *__pdata, int cpu)
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{
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struct percpu_data *pdata = __percpu_disguise(__pdata);
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kfree(pdata->ptrs[cpu]);
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pdata->ptrs[cpu] = NULL;
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}
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/**
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* percpu_depopulate_mask - depopulate per-cpu data for some cpu's
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* @__pdata: per-cpu data to depopulate
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* @mask: depopulate per-cpu data for cpu's selected through mask bits
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*/
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static void __percpu_depopulate_mask(void *__pdata, const cpumask_t *mask)
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{
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int cpu;
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for_each_cpu_mask_nr(cpu, *mask)
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percpu_depopulate(__pdata, cpu);
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}
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#define percpu_depopulate_mask(__pdata, mask) \
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__percpu_depopulate_mask((__pdata), &(mask))
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/**
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* percpu_populate - populate per-cpu data for given cpu
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* @__pdata: per-cpu data to populate further
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* @size: size of per-cpu object
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* @gfp: may sleep or not etc.
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* @cpu: populate per-data for this cpu
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*
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* Populating per-cpu data for a cpu coming online would be a typical
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* use case. You need to register a cpu hotplug handler for that purpose.
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* Per-cpu object is populated with zeroed buffer.
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*/
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static void *percpu_populate(void *__pdata, size_t size, gfp_t gfp, int cpu)
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{
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struct percpu_data *pdata = __percpu_disguise(__pdata);
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int node = cpu_to_node(cpu);
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/*
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* We should make sure each CPU gets private memory.
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*/
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size = roundup(size, cache_line_size());
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BUG_ON(pdata->ptrs[cpu]);
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if (node_online(node))
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pdata->ptrs[cpu] = kmalloc_node(size, gfp|__GFP_ZERO, node);
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else
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pdata->ptrs[cpu] = kzalloc(size, gfp);
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return pdata->ptrs[cpu];
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}
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/**
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* percpu_populate_mask - populate per-cpu data for more cpu's
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* @__pdata: per-cpu data to populate further
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* @size: size of per-cpu object
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* @gfp: may sleep or not etc.
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* @mask: populate per-cpu data for cpu's selected through mask bits
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*
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* Per-cpu objects are populated with zeroed buffers.
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*/
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static int __percpu_populate_mask(void *__pdata, size_t size, gfp_t gfp,
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cpumask_t *mask)
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{
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cpumask_t populated;
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int cpu;
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cpus_clear(populated);
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for_each_cpu_mask_nr(cpu, *mask)
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if (unlikely(!percpu_populate(__pdata, size, gfp, cpu))) {
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__percpu_depopulate_mask(__pdata, &populated);
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return -ENOMEM;
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} else
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cpu_set(cpu, populated);
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return 0;
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}
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#define percpu_populate_mask(__pdata, size, gfp, mask) \
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__percpu_populate_mask((__pdata), (size), (gfp), &(mask))
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/**
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* alloc_percpu - initial setup of per-cpu data
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* @size: size of per-cpu object
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* @align: alignment
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*
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* Allocate dynamic percpu area. Percpu objects are populated with
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* zeroed buffers.
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*/
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void *__alloc_percpu(size_t size, size_t align)
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{
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/*
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* We allocate whole cache lines to avoid false sharing
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*/
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size_t sz = roundup(nr_cpu_ids * sizeof(void *), cache_line_size());
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void *pdata = kzalloc(sz, GFP_KERNEL);
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void *__pdata = __percpu_disguise(pdata);
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/*
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* Can't easily make larger alignment work with kmalloc. WARN
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* on it. Larger alignment should only be used for module
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* percpu sections on SMP for which this path isn't used.
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*/
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WARN_ON_ONCE(align > SMP_CACHE_BYTES);
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if (unlikely(!pdata))
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return NULL;
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if (likely(!__percpu_populate_mask(__pdata, size, GFP_KERNEL,
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&cpu_possible_map)))
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return __pdata;
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kfree(pdata);
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return NULL;
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}
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EXPORT_SYMBOL_GPL(__alloc_percpu);
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/**
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* free_percpu - final cleanup of per-cpu data
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* @__pdata: object to clean up
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*
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* We simply clean up any per-cpu object left. No need for the client to
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* track and specify through a bis mask which per-cpu objects are to free.
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*/
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void free_percpu(void *__pdata)
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{
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if (unlikely(!__pdata))
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return;
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__percpu_depopulate_mask(__pdata, cpu_possible_mask);
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kfree(__percpu_disguise(__pdata));
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}
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EXPORT_SYMBOL_GPL(free_percpu);
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