From: Dennis Zhou <dennis@kernel.org>
To: Tejun Heo <tj@kernel.org>, Christoph Lameter <cl@linux.com>,
Roman Gushchin <guro@fb.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Dennis Zhou <dennis@kernel.org>
Subject: [PATCH 1/4] percpu: factor out pcpu_check_block_hint()
Date: Mon, 19 Apr 2021 22:50:44 +0000 [thread overview]
Message-ID: <20210419225047.3415425-2-dennis@kernel.org> (raw)
In-Reply-To: <20210419225047.3415425-1-dennis@kernel.org>
From: Roman Gushchin <guro@fb.com>
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: Roman Gushchin <guro@fb.com>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
---
mm/percpu.c | 30 +++++++++++++++++++++++-------
1 file changed, 23 insertions(+), 7 deletions(-)
diff --git a/mm/percpu.c b/mm/percpu.c
index 61339b3d9337..5edc7bd88133 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -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.
+ * 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.
*/
- bit_off = ALIGN(chunk_md->contig_hint_start, align) -
- chunk_md->contig_hint_start;
- if (bit_off + alloc_bits > chunk_md->contig_hint)
+ if (!pcpu_check_block_hint(chunk_md, alloc_bits, align))
return -1;
bit_off = pcpu_next_hint(chunk_md, alloc_bits);
--
2.31.1.368.gbe11c130af-goog
next prev parent reply other threads:[~2021-04-19 22:51 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-19 22:50 [PATCH v4 0/4] percpu: partial chunk depopulation Dennis Zhou
2021-04-19 22:50 ` Dennis Zhou [this message]
2021-04-19 22:50 ` [PATCH 2/4] percpu: use pcpu_free_slot instead of pcpu_nr_slots - 1 Dennis Zhou
2021-04-20 21:22 ` Roman Gushchin
2021-04-19 22:50 ` [PATCH 3/4] percpu: implement partial chunk depopulation Dennis Zhou
2021-07-02 19:11 ` Guenter Roeck
2021-07-02 19:45 ` Dennis Zhou
2021-07-02 20:28 ` Guenter Roeck
2021-07-02 21:00 ` Dennis Zhou
2021-04-19 22:50 ` [PATCH 4/4] percpu: use reclaim threshold instead of running for every page Dennis Zhou
2021-04-20 21:23 ` Roman Gushchin
2021-04-19 22:54 ` [PATCH v4 0/4] percpu: partial chunk depopulation Dennis Zhou
2021-04-19 22:57 ` Dennis Zhou
2021-04-20 11:07 ` Pratik Sampat
2021-04-20 14:39 ` Dennis Zhou
2021-04-20 15:25 ` Pratik Sampat
2021-04-21 18:24 ` Dennis Zhou
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