GitHub-Mirror/Star64_linux
2
0
Fork 0
mirror of https://github.com/Fishwaldo/Star64_linux.git synced 2025-06-28 01:21:58 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

ida: Move ida_bitmap to a percpu variable

Browse source 
When we preload the IDA, we allocate an IDA bitmap.  Instead of storing
that preallocated bitmap in the IDA, we store it in a percpu variable.
Generally there are more IDAs in the system than CPUs, so this cuts down
on the number of preallocated bitmaps that are unused, and about half
of the IDA users did not call ida_destroy() so they were leaking IDA
bitmaps.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
This commit is contained in:
Matthew Wilcox 2016-12-16 11:55:56 -05:00
parent 0a835c4f09
commit 7ad3d4d85c
5 changed files with 51 additions and 45 deletions
Download patch file Download diff file Expand all files Collapse all files

45
lib/radix-tree.c
View file

@ -69,6 +69,14 @@ static struct kmem_cache *radix_tree_node_cachep;
RADIX_TREE_MAP_SHIFT))
#define IDR_PRELOAD_SIZE (IDR_MAX_PATH * 2 - 1)
/*
* The IDA is even shorter since it uses a bitmap at the last level.
*/
#define IDA_INDEX_BITS (8 * sizeof(int) - 1 - ilog2(IDA_BITMAP_BITS))
#define IDA_MAX_PATH (DIV_ROUND_UP(IDA_INDEX_BITS, \
RADIX_TREE_MAP_SHIFT))
#define IDA_PRELOAD_SIZE (IDA_MAX_PATH * 2 - 1)
/*
* Per-cpu pool of preloaded nodes
*/
@ -346,9 +354,8 @@ static void dump_ida_node(void *entry, unsigned long index)
static void ida_dump(struct ida *ida)
{
struct radix_tree_root *root = &ida->ida_rt;
pr_debug("ida: %p %p free %d bitmap %p\n", ida, root->rnode,
root->gfp_mask >> ROOT_TAG_SHIFT,
ida->free_bitmap);
pr_debug("ida: %p node %p free %d\n", ida, root->rnode,
root->gfp_mask >> ROOT_TAG_SHIFT);
dump_ida_node(root->rnode, 0);
}
#endif
@ -2080,6 +2087,36 @@ void idr_preload(gfp_t gfp_mask)
}
EXPORT_SYMBOL(idr_preload);
/**
* ida_pre_get - reserve resources for ida allocation
* @ida: ida handle
* @gfp: memory allocation flags
*
* This function should be called before calling ida_get_new_above(). If it
* is unable to allocate memory, it will return %0. On success, it returns %1.
*/
int ida_pre_get(struct ida *ida, gfp_t gfp)
{
__radix_tree_preload(gfp, IDA_PRELOAD_SIZE);
/*
* The IDA API has no preload_end() equivalent. Instead,
* ida_get_new() can return -EAGAIN, prompting the caller
* to return to the ida_pre_get() step.
*/
preempt_enable();
if (!this_cpu_read(ida_bitmap)) {
struct ida_bitmap *bitmap = kmalloc(sizeof(*bitmap), gfp);
if (!bitmap)
return 0;
bitmap = this_cpu_cmpxchg(ida_bitmap, NULL, bitmap);
kfree(bitmap);
}
return 1;
}
EXPORT_SYMBOL(ida_pre_get);
void **idr_get_free(struct radix_tree_root *root,
struct radix_tree_iter *iter, gfp_t gfp, int end)
{
@ -2219,6 +2256,8 @@ static int radix_tree_cpu_dead(unsigned int cpu)
kmem_cache_free(radix_tree_node_cachep, node);
rtp->nr--;
}
kfree(per_cpu(ida_bitmap, cpu));
per_cpu(ida_bitmap, cpu) = NULL;
return 0;
}