fs/squashfs/file_direct.c: replace count*size kmalloc by kmalloc_array

2014-08-07T01:01:13+00:00

kmalloc_array() manages count*sizeof overflow. Signed-off-by: Fabian Frederick Cc: Phillip Lougher Cc: Joe Perches Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Squashfs: fix failure to unlock pages on decompress error

2013-11-24T01:02:50+00:00

Direct decompression into the page cache. If we fall back to using an intermediate buffer (because we cannot grab all the page cache pages) and we get a decompress fail, we forgot to release the pages. Reported-by: Roman Peniaev Signed-off-by: Phillip Lougher

Squashfs: Directly decompress into the page cache for file data

2013-11-20T03:59:13+00:00

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 Reviewed-by: Minchan Kim

BMC/Intel-BMC/linux.git/fs/squashfs/file_direct.c, branch dev

fs/squashfs/file_direct.c: replace count*size kmalloc by kmalloc_array

Squashfs: fix failure to unlock pages on decompress error

Squashfs: Directly decompress into the page cache for file data