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author | Jan Weitzel <j.weitzel@phytec.de> | 2012-05-16 08:10:16 +0200 |
---|---|---|
committer | Sascha Hauer <s.hauer@pengutronix.de> | 2012-05-16 13:20:09 +0200 |
commit | 011801d22c7da29d62a7321afb4894f2618c3a9d (patch) | |
tree | f8d1b806ede3894b18061027283b433937c9b120 /fs | |
parent | 3f66e8dc57d0dd05e22d321786da39810ba6b7ff (diff) | |
download | barebox-011801d22c7da29d62a7321afb4894f2618c3a9d.tar.gz barebox-011801d22c7da29d62a7321afb4894f2618c3a9d.tar.xz |
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>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/ramfs.c | 47 |
1 files changed, 37 insertions, 10 deletions
diff --git a/fs/ramfs.c b/fs/ramfs.c index 83ab6dfc06..cec5e769b0 100644 --- a/fs/ramfs.c +++ b/fs/ramfs.c @@ -48,6 +48,10 @@ struct ramfs_inode { ulong size; struct ramfs_chunk *data; + + /* Points to recently used chunk */ + int recent_chunk; + struct ramfs_chunk *recent_chunkp; }; struct ramfs_priv { @@ -297,6 +301,35 @@ static int ramfs_close(struct device_d *dev, FILE *f) return 0; } +static struct ramfs_chunk *ramfs_find_chunk(struct ramfs_inode *node, int chunk) +{ + struct ramfs_chunk *data; + int left = chunk; + + if (chunk == 0) + return node->data; + + if (node->recent_chunk == chunk) + return node->recent_chunkp; + + if (node->recent_chunk < chunk && node->recent_chunk != 0) { + /* Start at last known chunk */ + data = node->recent_chunkp; + left -= node->recent_chunk; + } else { + /* Start at first chunk */ + data = node->data; + } + + while (left--) + data = data->next; + + node->recent_chunkp = data; + node->recent_chunk = chunk; + + return data; +} + static int ramfs_read(struct device_d *_dev, FILE *f, void *buf, size_t insize) { struct ramfs_inode *node = (struct ramfs_inode *)f->inode; @@ -311,11 +344,7 @@ static int ramfs_read(struct device_d *_dev, FILE *f, void *buf, size_t insize) debug("%s: reading from chunk %d\n", __FUNCTION__, chunk); /* Position ourself in stream */ - data = node->data; - while (chunk) { - data = data->next; - chunk--; - } + data = ramfs_find_chunk(node, chunk); ofs = f->pos % CHUNK_SIZE; /* Read till end of current chunk */ @@ -364,11 +393,7 @@ static int ramfs_write(struct device_d *_dev, FILE *f, const void *buf, size_t i debug("%s: writing to chunk %d\n", __FUNCTION__, chunk); /* Position ourself in stream */ - data = node->data; - while (chunk) { - data = data->next; - chunk--; - } + data = ramfs_find_chunk(node, chunk); ofs = f->pos % CHUNK_SIZE; /* Write till end of current chunk */ @@ -429,6 +454,8 @@ static int ramfs_truncate(struct device_d *dev, FILE *f, ulong size) ramfs_put_chunk(data); data = tmp; } + if (node->recent_chunk > newchunks) + node->recent_chunk = 0; } if (newchunks > oldchunks) { |