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authorPhillip Lougher <phillip@squashfs.org.uk>2013-11-13 02:04:19 +0000
committerPhillip Lougher <phillip@squashfs.org.uk>2013-11-20 03:59:13 +0000
commit0d455c12c6428647547bacccaaced3cae0f35570 (patch)
treea0c47256d66de9d70942b0d7f9422c8d7d5c5a41 /fs/squashfs/Makefile
parent5f55dbc0c5c466a9cdfa4da7ac1bfe351c7fc52a (diff)
downloadop-kernel-dev-0d455c12c6428647547bacccaaced3cae0f35570.zip
op-kernel-dev-0d455c12c6428647547bacccaaced3cae0f35570.tar.gz
Squashfs: Directly decompress into the page cache for file data
This introduces an implementation of squashfs_readpage_block() that directly decompresses into the page cache. This uses the previously added page handler abstraction to push down the necessary kmap_atomic/kunmap_atomic operations on the page cache buffers into the decompressors. This enables direct copying into the page cache without using the slow kmap/kunmap calls. The code detects when multiple threads are racing in squashfs_readpage() to decompress the same block, and avoids this regression by falling back to using an intermediate buffer. This patch enhances the performance of Squashfs significantly when multiple processes are accessing the filesystem simultaneously because it not only reduces memcopying, but it more importantly eliminates the lock contention on the intermediate buffer. Using single-thread decompression. dd if=file1 of=/dev/null bs=4096 & dd if=file2 of=/dev/null bs=4096 & dd if=file3 of=/dev/null bs=4096 & dd if=file4 of=/dev/null bs=4096 Before: 629145600 bytes (629 MB) copied, 45.8046 s, 13.7 MB/s After: 629145600 bytes (629 MB) copied, 9.29414 s, 67.7 MB/s Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk> Reviewed-by: Minchan Kim <minchan@kernel.org>
Diffstat (limited to 'fs/squashfs/Makefile')
-rw-r--r--fs/squashfs/Makefile4
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/squashfs/Makefile b/fs/squashfs/Makefile
index e01ba11..4132520 100644
--- a/fs/squashfs/Makefile
+++ b/fs/squashfs/Makefile
@@ -4,7 +4,9 @@
obj-$(CONFIG_SQUASHFS) += squashfs.o
squashfs-y += block.o cache.o dir.o export.o file.o fragment.o id.o inode.o
-squashfs-y += namei.o super.o symlink.o decompressor.o file_cache.o
+squashfs-y += namei.o super.o symlink.o decompressor.o
+squashfs-$(CONFIG_SQUASHFS_FILE_CACHE) += file_cache.o
+squashfs-$(CONFIG_SQUASHFS_FILE_DIRECT) += file_direct.o page_actor.o
squashfs-$(CONFIG_SQUASHFS_DECOMP_SINGLE) += decompressor_single.o
squashfs-$(CONFIG_SQUASHFS_DECOMP_MULTI) += decompressor_multi.o
squashfs-$(CONFIG_SQUASHFS_DECOMP_MULTI_PERCPU) += decompressor_multi_percpu.o
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