Commit 8ea2e1e3 authored by Roman Gushchin's avatar Roman Gushchin Committed by Dennis Zhou
Browse files

percpu: factor out pcpu_check_block_hint() 



Factor out the pcpu_check_block_hint() helper, which will be useful
in the future. The new function checks if the allocation can likely
fit within the contig hint.

Signed-off-by: default avatarRoman Gushchin <guro@fb.com>
Signed-off-by: default avatarDennis Zhou <dennis@kernel.org>
Signed-off-by: default avatarDennis Zhou <dennis@kernel.org>
parent 67c2669d

mm/percpu.c

+23 −7
Original line number Diff line number Diff line
@@ -306,6 +306,25 @@ static unsigned long pcpu_block_off_to_off(int index, int off) 
	return index * PCPU_BITMAP_BLOCK_BITS + off;

}



/**

 * pcpu_check_block_hint - check against the contig hint

 * @block: block of interest

 * @bits: size of allocation

 * @align: alignment of area (max PAGE_SIZE)

 *

 * Check to see if the allocation can fit in the block's contig hint.

 * Note, a chunk uses the same hints as a block so this can also check against

 * the chunk's contig hint.

 */

static bool pcpu_check_block_hint(struct pcpu_block_md *block, int bits,

				  size_t align)

{

	int bit_off = ALIGN(block->contig_hint_start, align) -

		block->contig_hint_start;



	return bit_off + bits <= block->contig_hint;

}



/*

 * pcpu_next_hint - determine which hint to use

 * @block: block of interest
@@ -1066,14 +1085,11 @@ static int pcpu_find_block_fit(struct pcpu_chunk *chunk, int alloc_bits, 
	int bit_off, bits, next_off;



	/*

	 * Check to see if the allocation can fit in the chunk's contig hint.

	 * This is an optimization to prevent scanning by assuming if it

	 * cannot fit in the global hint, there is memory pressure and creating

	 * a new chunk would happen soon.

	 */

	bit_off = ALIGN(chunk_md->contig_hint_start, align) -

		  chunk_md->contig_hint_start;

	if (bit_off + alloc_bits > chunk_md->contig_hint)

	 * This is an optimization to prevent scanning by assuming if the

	 * allocation cannot fit in the global hint, there is memory pressure

	 * and creating a new chunk would happen soon.

	 */

	if (!pcpu_check_block_hint(chunk_md, alloc_bits, align))

		return -1;



	bit_off = pcpu_next_hint(chunk_md, alloc_bits);