ramfs: rember last accessed chunk
Writing big files takes longer and longer because of the chunk list By storing a pointer of the recent used chunk in the inode, access times are improved. Testet on with tftp 10M: OMAP4 chunk size 4096: 12244ms 8192: 4239ms patched 2647ms 2785ms i.MX35 chunk size 8192: 7225ms patched 2691ms No impact on much smaller files seen Signed-off-by: Jan Weitzel <j.weitzel@phytec.de> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
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parent
3f66e8dc57
commit
011801d22c
47
fs/ramfs.c
47
fs/ramfs.c
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@ -48,6 +48,10 @@ struct ramfs_inode {
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ulong size;
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struct ramfs_chunk *data;
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/* Points to recently used chunk */
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int recent_chunk;
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struct ramfs_chunk *recent_chunkp;
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};
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struct ramfs_priv {
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@ -297,6 +301,35 @@ static int ramfs_close(struct device_d *dev, FILE *f)
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return 0;
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}
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static struct ramfs_chunk *ramfs_find_chunk(struct ramfs_inode *node, int chunk)
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{
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struct ramfs_chunk *data;
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int left = chunk;
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if (chunk == 0)
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return node->data;
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if (node->recent_chunk == chunk)
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return node->recent_chunkp;
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if (node->recent_chunk < chunk && node->recent_chunk != 0) {
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/* Start at last known chunk */
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data = node->recent_chunkp;
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left -= node->recent_chunk;
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} else {
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/* Start at first chunk */
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data = node->data;
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}
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while (left--)
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data = data->next;
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node->recent_chunkp = data;
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node->recent_chunk = chunk;
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return data;
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}
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static int ramfs_read(struct device_d *_dev, FILE *f, void *buf, size_t insize)
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{
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struct ramfs_inode *node = (struct ramfs_inode *)f->inode;
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@ -311,11 +344,7 @@ static int ramfs_read(struct device_d *_dev, FILE *f, void *buf, size_t insize)
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debug("%s: reading from chunk %d\n", __FUNCTION__, chunk);
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/* Position ourself in stream */
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data = node->data;
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while (chunk) {
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data = data->next;
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chunk--;
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}
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data = ramfs_find_chunk(node, chunk);
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ofs = f->pos % CHUNK_SIZE;
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/* Read till end of current chunk */
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@ -364,11 +393,7 @@ static int ramfs_write(struct device_d *_dev, FILE *f, const void *buf, size_t i
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debug("%s: writing to chunk %d\n", __FUNCTION__, chunk);
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/* Position ourself in stream */
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data = node->data;
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while (chunk) {
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data = data->next;
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chunk--;
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}
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data = ramfs_find_chunk(node, chunk);
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ofs = f->pos % CHUNK_SIZE;
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/* Write till end of current chunk */
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@ -429,6 +454,8 @@ static int ramfs_truncate(struct device_d *dev, FILE *f, ulong size)
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ramfs_put_chunk(data);
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data = tmp;
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}
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if (node->recent_chunk > newchunks)
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node->recent_chunk = 0;
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}
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if (newchunks > oldchunks) {
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