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Rename kernel cache options

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Thanks to @cipriancraciun for suggesting way better names
This commit is contained in:
Marcus Holland-Moritz 2020-12-03 12:55:10 +01:00
parent 34b3de12c2
commit 70c2a97fdd
2 changed files with 32 additions and 25 deletions
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35
doc/dwarfs.md
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@ -64,25 +64,28 @@ options:
will also consume more memory to hold the hardlink count table.
This will be 4 bytes for every regular file inode.
* `-o no_image_madvise`
By default, `dwarfs` will issue `madvise` calls after reading
the compressed block data from the file system image. This
will reduce the memory consumption of the FUSE driver to
slightly more than the `cachesize`. This usually isn't a
problem, especially when the image is stored on an SSD, but if
you want to maximize performance it can be beneficial to use
this option to keep the compressed image data in the kernel
* `-o (no_)cache_image`
By default, `dwarfs` tries to ensure that the compressed file
system image will not be cached by the kernel (i.e. the default
is `-o no_cache_image`). This will reduce the memory consumption
of the FUSE driver to slightly more than the `cachesize`, plus
the size of the metadata block. This usually isn't a problem,
especially when the image is stored on an SSD, but if you want
to maximize performance it can be beneficial to use
`-o cache_image` to keep the compressed image data in the kernel
cache.
* `-o direct_io`
* `-o (no_)cache_files`
By default, files in the mounted file system will be cached by
the kernel. This significantly improves performance when accessing
the same files over and over again, especially if the data from
these files has been (partially) evicted from the block cache of
`dwarfs`. By setting this option, you can force the fuse driver
to not use the kernel cache for file data. If you're short on
memory and only infrequently accessing files, this can be worth
trying.
the kernel (i.e. the default is `-o cache_files`). This will
significantly improve performance when accessing the same files
over and over again, especially if the data from these files has
been (partially) evicted from the block cache. By setting the
`-o no_cache_files` option, you can force the fuse driver to not
use the kernel cache for file data. If you're short on memory and
only infrequently accessing files, this can be worth trying, even
though it's likely that the kernel will already do the right thing
even when the cache is enabled.
* `-o debuglevel=`*name*:
Use this for different levels of verbosity along with either

22
src/dwarfs.cpp
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@ -53,8 +53,8 @@ struct options {
const char* mlock_str; // TODO: const?? -> use string?
const char* decompress_ratio_str; // TODO: const?? -> use string?
int enable_nlink;
int no_image_madvise;
int direct_io;
int cache_image;
int cache_files;
size_t cachesize;
size_t workers;
mlock_mode lock_mode;
@ -79,8 +79,10 @@ const struct fuse_opt dwarfs_opts[] = {
DWARFS_OPT("mlock=%s", mlock_str, 0),
DWARFS_OPT("decratio=%s", decompress_ratio_str, 0),
DWARFS_OPT("enable_nlink", enable_nlink, 1),
DWARFS_OPT("no_image_madvise", no_image_madvise, 1),
DWARFS_OPT("direct_io", direct_io, 1),
DWARFS_OPT("cache_image", cache_image, 1),
DWARFS_OPT("no_cache_image", cache_image, 0),
DWARFS_OPT("cache_files", cache_files, 1),
DWARFS_OPT("no_cache_files", cache_files, 0),
FUSE_OPT_END};
options s_opts;
@ -101,7 +103,7 @@ void op_init(void* /*userdata*/, struct fuse_conn_info* /*conn*/) {
fsopts.block_cache.max_bytes = s_opts.cachesize;
fsopts.block_cache.num_workers = s_opts.workers;
fsopts.block_cache.decompress_ratio = s_opts.decompress_ratio;
fsopts.block_cache.mm_release = !s_opts.no_image_madvise;
fsopts.block_cache.mm_release = !s_opts.cache_image;
fsopts.metadata.enable_nlink = bool(s_opts.enable_nlink);
s_fs = std::make_shared<filesystem_v2>(
s_lgr, std::make_shared<mmap>(s_opts.fsimage), fsopts,
@ -254,8 +256,8 @@ void op_open(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info* fi) {
err = EACCES;
} else {
fi->fh = FUSE_ROOT_ID + entry->inode();
fi->direct_io = s_opts.direct_io;
fi->keep_cache = !s_opts.direct_io;
fi->direct_io = !s_opts.cache_files;
fi->keep_cache = s_opts.cache_files;
fuse_reply_open(req, fi);
return;
}
@ -398,8 +400,8 @@ void usage(const char* progname) {
<< " -o mlock=NAME mlock mode: (none), try, must\n"
<< " -o decratio=NUM ratio for full decompression (0.8)\n"
<< " -o enable_nlink show correct hardlink numbers\n"
<< " -o no_image_madvise keep image in kernel cache\n"
<< " -o direct_io don't keep files in kernel cache\n"
<< " -o (no_)cache_image (don't) keep image in kernel cache\n"
<< " -o (no_)cache_files (don't) keep files in kernel cache\n"
<< " -o debuglevel=NAME error, warn, (info), debug, trace\n"
<< std::endl;
@ -498,6 +500,8 @@ int main(int argc, char* argv[]) {
struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
s_opts.progname = argv[0];
s_opts.cache_image = 0;
s_opts.cache_files = 1;
fuse_opt_parse(&args, &s_opts, dwarfs_opts, option_hdl);