From d208383d640727b70cd6689bc17e67e9b5ebf4ff Mon Sep 17 00:00:00 2001 From: Phillip Lougher Date: Mon, 18 Nov 2013 02:31:36 +0000 Subject: Squashfs: add multi-threaded decompression using percpu variable Add a multi-threaded decompression implementation which uses percpu variables. Using percpu variables has advantages and disadvantages over implementations which do not use percpu variables. Advantages: * the nature of percpu variables ensures decompression is load-balanced across the multiple cores. * simplicity. Disadvantages: it limits decompression to one thread per core. Signed-off-by: Phillip Lougher --- fs/squashfs/decompressor_multi_percpu.c | 98 +++++++++++++++++++++++++++++++++ 1 file changed, 98 insertions(+) create mode 100644 fs/squashfs/decompressor_multi_percpu.c (limited to 'fs/squashfs/decompressor_multi_percpu.c') diff --git a/fs/squashfs/decompressor_multi_percpu.c b/fs/squashfs/decompressor_multi_percpu.c new file mode 100644 index 000000000000..0e7b679bc4ad --- /dev/null +++ b/fs/squashfs/decompressor_multi_percpu.c @@ -0,0 +1,98 @@ +/* + * Copyright (c) 2013 + * Phillip Lougher + * + * This work is licensed under the terms of the GNU GPL, version 2. See + * the COPYING file in the top-level directory. + */ + +#include +#include +#include +#include + +#include "squashfs_fs.h" +#include "squashfs_fs_sb.h" +#include "decompressor.h" +#include "squashfs.h" + +/* + * This file implements multi-threaded decompression using percpu + * variables, one thread per cpu core. + */ + +struct squashfs_stream { + void *stream; +}; + +void *squashfs_decompressor_create(struct squashfs_sb_info *msblk, + void *comp_opts) +{ + struct squashfs_stream *stream; + struct squashfs_stream __percpu *percpu; + int err, cpu; + + percpu = alloc_percpu(struct squashfs_stream); + if (percpu == NULL) + return ERR_PTR(-ENOMEM); + + for_each_possible_cpu(cpu) { + stream = per_cpu_ptr(percpu, cpu); + stream->stream = msblk->decompressor->init(msblk, comp_opts); + if (IS_ERR(stream->stream)) { + err = PTR_ERR(stream->stream); + goto out; + } + } + + kfree(comp_opts); + return (__force void *) percpu; + +out: + for_each_possible_cpu(cpu) { + stream = per_cpu_ptr(percpu, cpu); + if (!IS_ERR_OR_NULL(stream->stream)) + msblk->decompressor->free(stream->stream); + } + free_percpu(percpu); + return ERR_PTR(err); +} + +void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk) +{ + struct squashfs_stream __percpu *percpu = + (struct squashfs_stream __percpu *) msblk->stream; + struct squashfs_stream *stream; + int cpu; + + if (msblk->stream) { + for_each_possible_cpu(cpu) { + stream = per_cpu_ptr(percpu, cpu); + msblk->decompressor->free(stream->stream); + } + free_percpu(percpu); + } +} + +int squashfs_decompress(struct squashfs_sb_info *msblk, + void **buffer, struct buffer_head **bh, int b, int offset, int length, + int srclength, int pages) +{ + struct squashfs_stream __percpu *percpu = + (struct squashfs_stream __percpu *) msblk->stream; + struct squashfs_stream *stream = get_cpu_ptr(percpu); + int res = msblk->decompressor->decompress(msblk, stream->stream, buffer, + bh, b, offset, length, srclength, pages); + put_cpu_ptr(stream); + + if (res < 0) + ERROR("%s decompression failed, data probably corrupt\n", + msblk->decompressor->name); + + return res; +} + +int squashfs_max_decompressors(void) +{ + return num_possible_cpus(); +} -- cgit v1.2.2 From 846b730e99518a1c9945afcb2afbe4d08a02ed80 Mon Sep 17 00:00:00 2001 From: Phillip Lougher Date: Mon, 18 Nov 2013 02:59:12 +0000 Subject: Squashfs: Generalise paging handling in the decompressors Further generalise the decompressors by adding a page handler abstraction. This adds helpers to allow the decompressors to access and process the output buffers in an implementation independant manner. This allows different types of output buffer to be passed to the decompressors, with the implementation specific aspects handled at decompression time, but without the knowledge being held in the decompressor wrapper code. This will allow the decompressors to handle Squashfs cache buffers, and page cache pages. This patch adds the abstraction and an implementation for the caches. Signed-off-by: Phillip Lougher Reviewed-by: Minchan Kim --- fs/squashfs/decompressor_multi_percpu.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'fs/squashfs/decompressor_multi_percpu.c') diff --git a/fs/squashfs/decompressor_multi_percpu.c b/fs/squashfs/decompressor_multi_percpu.c index 0e7b679bc4ad..23a9c28ad8ea 100644 --- a/fs/squashfs/decompressor_multi_percpu.c +++ b/fs/squashfs/decompressor_multi_percpu.c @@ -74,15 +74,14 @@ void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk) } } -int squashfs_decompress(struct squashfs_sb_info *msblk, - void **buffer, struct buffer_head **bh, int b, int offset, int length, - int srclength, int pages) +int squashfs_decompress(struct squashfs_sb_info *msblk, struct buffer_head **bh, + int b, int offset, int length, struct squashfs_page_actor *output) { struct squashfs_stream __percpu *percpu = (struct squashfs_stream __percpu *) msblk->stream; struct squashfs_stream *stream = get_cpu_ptr(percpu); - int res = msblk->decompressor->decompress(msblk, stream->stream, buffer, - bh, b, offset, length, srclength, pages); + int res = msblk->decompressor->decompress(msblk, stream->stream, bh, b, + offset, length, output); put_cpu_ptr(stream); if (res < 0) -- cgit v1.2.2