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linux-next/fs/squashfs/decompressor_multi.c
Philippe Liard 93e72b3c61 squashfs: migrate from ll_rw_block usage to BIO
ll_rw_block() function has been deprecated in favor of BIO which appears
to come with large performance improvements.

This patch decreases boot time by close to 40% when using squashfs for
the root file-system.  This is observed at least in the context of
starting an Android VM on Chrome OS using crosvm.  The patch was tested
on 4.19 as well as master.

This patch is largely based on Adrien Schildknecht's patch that was
originally sent as https://lkml.org/lkml/2017/9/22/814 though with some
significant changes and simplifications while also taking Phillip
Lougher's feedback into account, around preserving support for
FILE_CACHE in particular.

[akpm@linux-foundation.org: fix build error reported by Randy]
  Link: http://lkml.kernel.org/r/319997c2-5fc8-f889-2ea3-d913308a7c1f@infradead.org
Signed-off-by: Philippe Liard <pliard@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Adrien Schildknecht <adrien+dev@schischi.me>
Cc: Phillip Lougher <phillip@squashfs.org.uk>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Daniel Rosenberg <drosen@google.com>
Link: https://chromium.googlesource.com/chromiumos/platform/crosvm
Link: http://lkml.kernel.org/r/20191106074238.186023-1-pliard@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-02 10:59:05 -07:00

198 lines
4.5 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2013
* Minchan Kim <minchan@kernel.org>
*/
#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/bio.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, struct bio *bio,
int offset, int length,
struct squashfs_page_actor *output)
{
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,
bio, offset, length, output);
put_decomp_stream(decomp_stream, stream);
if (res < 0)
ERROR("%s decompression failed, data probably corrupt\n",
msblk->decompressor->name);
return res;
}