On Fri, Mar 12, 2021 at 09:25:31PM +0900, Daeho Jeong wrote:
> From: Daeho Jeong <[email protected]>
>
> I've added new sysfs nodes to show runtime compression stat since mount.
> compr_written_block - show the block count written after compression
> compr_saved_block - show the saved block count with compression
> compr_new_inode - show the count of inode newly enabled for compression
>
> Signed-off-by: Daeho Jeong <[email protected]>
> ---
> v2: thanks to kernel test robot <[email protected]>, fixed compile issue
> related to kernel config
> v3: changed sysfs nodes' names and made them runtime stat, not
> persistent on disk
> v4: changed sysfs nodes' desctiption
> ---
> Documentation/ABI/testing/sysfs-fs-f2fs | 24 ++++++++++
> fs/f2fs/compress.c | 1 +
> fs/f2fs/f2fs.h | 19 ++++++++
> fs/f2fs/super.c | 7 +++
> fs/f2fs/sysfs.c | 58 +++++++++++++++++++++++++
> 5 files changed, 109 insertions(+)
>
> diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs
> b/Documentation/ABI/testing/sysfs-fs-f2fs
> index cbeac1bebe2f..ddd4bd6116fc 100644
> --- a/Documentation/ABI/testing/sysfs-fs-f2fs
> +++ b/Documentation/ABI/testing/sysfs-fs-f2fs
> @@ -409,3 +409,27 @@ Description: Give a way to change checkpoint merge
> daemon's io priority.
> I/O priority "3". We can select the class between "rt" and "be",
> and set the I/O priority within valid range of it. "," delimiter
> is necessary in between I/O class and priority number.
> +
> +What: /sys/fs/f2fs/<disk>/compr_written_block
> +Date: March 2021
> +Contact: "Daeho Jeong" <[email protected]>
> +Description: Show the block count written after compression since mount. Note
> + that when the compressed blocks are deleted, this count doesn't
> + decrease. If you write "0" here, you can initialize
> + compr_written_block and compr_saved_block to "0".
> +
> +What: /sys/fs/f2fs/<disk>/compr_saved_block
> +Date: March 2021
> +Contact: "Daeho Jeong" <[email protected]>
> +Description: Show the saved block count with compression since mount. Note
> + that when the compressed blocks are deleted, this count doesn't
> + decrease. If you write "0" here, you can initialize
> + compr_written_block and compr_saved_block to "0".
> +
> +What: /sys/fs/f2fs/<disk>/compr_new_inode
> +Date: March 2021
> +Contact: "Daeho Jeong" <[email protected]>
> +Description: Show the count of inode newly enabled for compression since
> mount.
> + Note that when the compression is disabled for the files, this
> count
> + doesn't decrease. If you write "0" here, you can initialize
> + compr_new_inode to "0".
> diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
> index 77fa342de38f..3c9d797dbdd6 100644
> --- a/fs/f2fs/compress.c
> +++ b/fs/f2fs/compress.c
> @@ -1353,6 +1353,7 @@ static int f2fs_write_compressed_pages(struct
> compress_ctx *cc,
> if (fio.compr_blocks)
> f2fs_i_compr_blocks_update(inode, fio.compr_blocks - 1, false);
> f2fs_i_compr_blocks_update(inode, cc->nr_cpages, true);
> + add_compr_block_stat(inode, cc->nr_cpages);
>
> set_inode_flag(cc->inode, FI_APPEND_WRITE);
> if (cc->cluster_idx == 0)
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index e2d302ae3a46..2c989f8caf05 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1623,6 +1623,11 @@ struct f2fs_sb_info {
> #ifdef CONFIG_F2FS_FS_COMPRESSION
> struct kmem_cache *page_array_slab; /* page array entry */
> unsigned int page_array_slab_size; /* default page array slab size
> */
> +
> + /* For runtime compression statistics */
> + atomic64_t compr_written_block;
> + atomic64_t compr_saved_block;
> + atomic_t compr_new_inode;
Why do you need these to be atomic? What requires this?
> +#ifdef CONFIG_F2FS_FS_COMPRESSION
> + if (!strcmp(a->attr.name, "compr_written_block")) {
> + u64 bcount;
> + int len;
> +
> + bcount = atomic64_read(&sbi->compr_written_block);
> +
> + len = scnprintf(buf, PAGE_SIZE, "%llu\n", bcount);
Please use sysfs_emit() for new sysfs entries like these. Makes it much
simpler.
And look, you really do not need an atomic value as this is just a
random number you are sending to userspace that could be stale the
minute you read from it.
Please just use a normal u64 and save the cpu sync for stuff like this.
thanks,
greg k-h
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