squashfs: Enhance parallel I/O (cd59c2ec) · Commits · 戴 / test

fs/squashfs/Kconfig

+13 −0

Original line number	Diff line number	Diff line
		@@ -63,6 +63,19 @@ config SQUASHFS_LZO

		If unsure, say N.

		config SQUASHFS_MULTI_DECOMPRESSOR
		bool "Use multiple decompressors for handling parallel I/O"
		depends on SQUASHFS
		help
		By default Squashfs uses a single decompressor but it gives
		poor performance on parallel I/O workloads when using multiple CPU
		machines due to waiting on decompressor availability.

		If you have a parallel I/O workload and your system has enough memory,
		using this option may improve overall I/O performance.

		If unsure, say N.

		config SQUASHFS_XZ
		bool "Include support for XZ compressed file systems"
		depends on SQUASHFS

fs/squashfs/Makefile

+8 −1

Original line number	Diff line number	Diff line
		@@ -4,8 +4,15 @@

		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 decompressor_single.o
		squashfs-y += namei.o super.o symlink.o decompressor.o

		squashfs-$(CONFIG_SQUASHFS_XATTR) += xattr.o xattr_id.o
		squashfs-$(CONFIG_SQUASHFS_LZO) += lzo_wrapper.o
		squashfs-$(CONFIG_SQUASHFS_XZ) += xz_wrapper.o
		squashfs-$(CONFIG_SQUASHFS_ZLIB) += zlib_wrapper.o

		ifdef CONFIG_SQUASHFS_MULTI_DECOMPRESSOR
		squashfs-y += decompressor_multi.o
		else
		squashfs-y += decompressor_single.o
		endif

fs/squashfs/decompressor_multi.c

0 → 100644

+200 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (c) 2013
		* Minchan Kim <minchan@kernel.org>
		*
		* This work is licensed under the terms of the GNU GPL, version 2. See
		* the COPYING file in the top-level directory.
		*/
		#include <linux/types.h>
		#include <linux/mutex.h>
		#include <linux/slab.h>
		#include <linux/buffer_head.h>
		#include <linux/sched.h>
		#include <linux/wait.h>
		#include <linux/cpumask.h>

		#include "squashfs_fs.h"
		#include "squashfs_fs_sb.h"
		#include "decompressor.h"
		#include "squashfs.h"

		/*
		* This file implements multi-threaded decompression in the
		* decompressor framework
		*/


		/*
		* The reason that multiply two is that a CPU can request new I/O
		* while it is waiting previous request.
		*/
		#define MAX_DECOMPRESSOR (num_online_cpus() * 2)


		int squashfs_max_decompressors(void)
		{
		return MAX_DECOMPRESSOR;
		}


		struct squashfs_stream {
		void *comp_opts;
		struct list_head strm_list;
		struct mutex mutex;
		int avail_decomp;
		wait_queue_head_t wait;
		};


		struct decomp_stream {
		void *stream;
		struct list_head list;
		};


		static void put_decomp_stream(struct decomp_stream *decomp_strm,
		struct squashfs_stream *stream)
		{
		mutex_lock(&stream->mutex);
		list_add(&decomp_strm->list, &stream->strm_list);
		mutex_unlock(&stream->mutex);
		wake_up(&stream->wait);
		}

		void squashfs_decompressor_create(struct squashfs_sb_info msblk,
		void *comp_opts)
		{
		struct squashfs_stream *stream;
		struct decomp_stream *decomp_strm = NULL;
		int err = -ENOMEM;

		stream = kzalloc(sizeof(*stream), GFP_KERNEL);
		if (!stream)
		goto out;

		stream->comp_opts = comp_opts;
		mutex_init(&stream->mutex);
		INIT_LIST_HEAD(&stream->strm_list);
		init_waitqueue_head(&stream->wait);

		/*
		* We should have a decompressor at least as default
		* so if we fail to allocate new decompressor dynamically,
		* we could always fall back to default decompressor and
		* file system works.
		*/
		decomp_strm = kmalloc(sizeof(*decomp_strm), GFP_KERNEL);
		if (!decomp_strm)
		goto out;

		decomp_strm->stream = msblk->decompressor->init(msblk,
		stream->comp_opts);
		if (IS_ERR(decomp_strm->stream)) {
		err = PTR_ERR(decomp_strm->stream);
		goto out;
		}

		list_add(&decomp_strm->list, &stream->strm_list);
		stream->avail_decomp = 1;
		return stream;

		out:
		kfree(decomp_strm);
		kfree(stream);
		return ERR_PTR(err);
		}


		void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
		{
		struct squashfs_stream *stream = msblk->stream;
		if (stream) {
		struct decomp_stream *decomp_strm;

		while (!list_empty(&stream->strm_list)) {
		decomp_strm = list_entry(stream->strm_list.prev,
		struct decomp_stream, list);
		list_del(&decomp_strm->list);
		msblk->decompressor->free(decomp_strm->stream);
		kfree(decomp_strm);
		stream->avail_decomp--;
		}
		}

		WARN_ON(stream->avail_decomp);
		kfree(stream->comp_opts);
		kfree(stream);
		}


		static struct decomp_stream get_decomp_stream(struct squashfs_sb_info msblk,
		struct squashfs_stream *stream)
		{
		struct decomp_stream *decomp_strm;

		while (1) {
		mutex_lock(&stream->mutex);

		/* There is available decomp_stream */
		if (!list_empty(&stream->strm_list)) {
		decomp_strm = list_entry(stream->strm_list.prev,
		struct decomp_stream, list);
		list_del(&decomp_strm->list);
		mutex_unlock(&stream->mutex);
		break;
		}

		/*
		* If there is no available decomp and already full,
		* let's wait for releasing decomp from other users.
		*/
		if (stream->avail_decomp >= MAX_DECOMPRESSOR)
		goto wait;

		/* Let's allocate new decomp */
		decomp_strm = kmalloc(sizeof(*decomp_strm), GFP_KERNEL);
		if (!decomp_strm)
		goto wait;

		decomp_strm->stream = msblk->decompressor->init(msblk,
		stream->comp_opts);
		if (IS_ERR(decomp_strm->stream)) {
		kfree(decomp_strm);
		goto wait;
		}

		stream->avail_decomp++;
		WARN_ON(stream->avail_decomp > MAX_DECOMPRESSOR);

		mutex_unlock(&stream->mutex);
		break;
		wait:
		/*
		* If system memory is tough, let's for other's
		* releasing instead of hurting VM because it could
		* make page cache thrashing.
		*/
		mutex_unlock(&stream->mutex);
		wait_event(stream->wait,
		!list_empty(&stream->strm_list));
		}

		return decomp_strm;
		}


		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 res;
		struct squashfs_stream *stream = msblk->stream;
		struct decomp_stream *decomp_stream = get_decomp_stream(msblk, stream);
		res = msblk->decompressor->decompress(msblk, decomp_stream->stream,
		buffer, bh, b, offset, length, srclength, pages);
		put_decomp_stream(decomp_stream, stream);
		if (res < 0)
		ERROR("%s decompression failed, data probably corrupt\n",
		msblk->decompressor->name);
		return res;
		}

Admin message