On Jan 21, 2014, at 4:59 PM, Andreas Rohner wrote:
> With this option the user can specify the minimal number of free/dead
> blocks before a segment can be cleaned.
"Free or dead" or "free and dead"? What do you mean by free blocks?
"Free blocks" sounds for me as blocks that I can allocate and to use
immediately without any operations. If you mean invalid blocks (blocks
that it was updated in this segment) then I need to do garbage collection
operation for making it free. So, free blocks are really confusing term. And
"dead blocks" sounds for me not very good.
> This is a threshold for the GC
> to prevent needless moving of data. If there are less free blocks
> to gain from cleaning a segment than the specified number, the GC will
> abort and try again with a different segment.
>
> By setting it to 0 this feature is effectively disabled.
>
> Signed-off-by: Andreas Rohner <andreas.rohner@xxxxxxx>
> ---
> include/nilfs_cleaner.h | 19 ++++++++++---------
> sbin/cleanerd/cldconfig.c | 40 +++++++++++++++++++++++++++++++++++++++
> sbin/cleanerd/cldconfig.h | 4 ++++
> sbin/cleanerd/cleanerd.c | 23 ++++++++++++++++++++++
> sbin/cleanerd/nilfs_cleanerd.conf | 9 +++++++++
> sbin/nilfs-clean/nilfs-clean.c | 18 ++++++++++++++----
> 6 files changed, 100 insertions(+), 13 deletions(-)
>
> diff --git a/include/nilfs_cleaner.h b/include/nilfs_cleaner.h
> index 0bf02aa..42c4aa7 100644
> --- a/include/nilfs_cleaner.h
> +++ b/include/nilfs_cleaner.h
> @@ -46,17 +46,18 @@ struct nilfs_cleaner_args {
> uint64_t start_segnum; /* start segment number */
> uint64_t nsegs; /* number of segments */
> uint32_t runtime; /* runtime in seconds */
> - uint32_t pad2;
> + uint32_t min_free_blocks_threshold;
> };
> /* valid flags */
> -#define NILFS_CLEANER_ARG_PROTECTION_PERIOD (1 << 0)
> -#define NILFS_CLEANER_ARG_NSEGMENTS_PER_CLEAN (1 << 1)
> -#define NILFS_CLEANER_ARG_CLEANING_INTERVAL (1 << 2)
> -#define NILFS_CLEANER_ARG_USAGE_RATE_THRESHOLD (1 << 3) /* reserved */
> -#define NILFS_CLEANER_ARG_START_SEGNUM (1 << 4) /* reserved */
> -#define NILFS_CLEANER_ARG_NSEGS (1 << 5) /* reserved */
> -#define NILFS_CLEANER_ARG_NPASSES (1 << 6) /* reserved */
> -#define NILFS_CLEANER_ARG_RUNTIME (1 << 7) /* reserved */
> +#define NILFS_CLEANER_ARG_PROTECTION_PERIOD (1 << 0)
> +#define NILFS_CLEANER_ARG_NSEGMENTS_PER_CLEAN (1 << 1)
> +#define NILFS_CLEANER_ARG_CLEANING_INTERVAL (1 << 2)
> +#define NILFS_CLEANER_ARG_USAGE_RATE_THRESHOLD (1 << 3) /* reserved */
> +#define NILFS_CLEANER_ARG_START_SEGNUM (1 << 4) /* reserved */
> +#define NILFS_CLEANER_ARG_NSEGS (1 << 5) /* reserved */
> +#define NILFS_CLEANER_ARG_NPASSES (1 << 6) /* reserved */
> +#define NILFS_CLEANER_ARG_RUNTIME (1 << 7) /* reserved */
> +#define NILFS_CLEANER_ARG_MIN_FREE_BLOCKS_THRESHOLD (1 << 8)
What about NILFS_CLEANER_ARG_MIN_FBLK_THRESHOLD?
But free blocks really confuse me.
>
> enum {
> NILFS_CLEANER_STATUS_IDLE,
> diff --git a/sbin/cleanerd/cldconfig.c b/sbin/cleanerd/cldconfig.c
> index 270d360..4d7589c 100644
> --- a/sbin/cleanerd/cldconfig.c
> +++ b/sbin/cleanerd/cldconfig.c
> @@ -456,6 +456,34 @@ nilfs_cldconfig_handle_mc_nsegments_per_clean(struct nilfs_cldconfig *config,
> }
>
> static int
> +nilfs_cldconfig_handle_min_free_blocks(struct nilfs_cldconfig *config,
> + char **tokens, size_t ntoks,
> + struct nilfs *nilfs)
> +{
> + unsigned long n;
> +
> + if (nilfs_cldconfig_get_ulong_argument(tokens, ntoks, &n) < 0)
> + return 0;
> +
> + config->cf_min_free_blocks_threshold = n;
> + return 0;
> +}
> +
> +static int
> +nilfs_cldconfig_handle_mc_min_free_blocks(struct nilfs_cldconfig *config,
> + char **tokens, size_t ntoks,
> + struct nilfs *nilfs)
> +{
> + unsigned long n;
> +
> + if (nilfs_cldconfig_get_ulong_argument(tokens, ntoks, &n) < 0)
> + return 0;
> +
> + config->cf_mc_min_free_blocks_threshold = n;
> + return 0;
> +}
> +
> +static int
> nilfs_cldconfig_handle_cleaning_interval(struct nilfs_cldconfig *config,
> char **tokens, size_t ntoks,
> struct nilfs *nilfs)
> @@ -576,6 +604,14 @@ nilfs_cldconfig_keyword_table[] = {
> "log_priority", 2, 2,
> nilfs_cldconfig_handle_log_priority
> },
> + {
> + "min_free_blocks_threshold", 2, 2,
> + nilfs_cldconfig_handle_min_free_blocks
> + },
> + {
> + "mc_min_free_blocks_threshold", 2, 2,
> + nilfs_cldconfig_handle_mc_min_free_blocks
> + },
> };
>
> #define NILFS_CLDCONFIG_NKEYWORDS \
> @@ -641,6 +677,10 @@ static void nilfs_cldconfig_set_default(struct nilfs_cldconfig *config,
> config->cf_retry_interval.tv_usec = 0;
> config->cf_use_mmap = NILFS_CLDCONFIG_USE_MMAP;
> config->cf_log_priority = NILFS_CLDCONFIG_LOG_PRIORITY;
> + config->cf_min_free_blocks_threshold =
> + NILFS_CLDCONFIG_MIN_FREE_BLOCKS_THRESHOLD;
> + config->cf_mc_min_free_blocks_threshold =
> + NILFS_CLDCONFIG_MC_MIN_FREE_BLOCKS_THRESHOLD;
> }
>
> static inline int iseol(int c)
> diff --git a/sbin/cleanerd/cldconfig.h b/sbin/cleanerd/cldconfig.h
> index 188ce9b..49ee6be 100644
> --- a/sbin/cleanerd/cldconfig.h
> +++ b/sbin/cleanerd/cldconfig.h
> @@ -102,6 +102,8 @@ struct nilfs_cldconfig {
> struct timeval cf_retry_interval;
> int cf_use_mmap;
> int cf_log_priority;
> + unsigned long cf_min_free_blocks_threshold;
> + unsigned long cf_mc_min_free_blocks_threshold;
> };
>
> #define NILFS_CLDCONFIG_SELECTION_POLICY_IMPORTANCE \
> @@ -120,6 +122,8 @@ struct nilfs_cldconfig {
> #define NILFS_CLDCONFIG_RETRY_INTERVAL 60
> #define NILFS_CLDCONFIG_USE_MMAP 1
> #define NILFS_CLDCONFIG_LOG_PRIORITY LOG_INFO
> +#define NILFS_CLDCONFIG_MIN_FREE_BLOCKS_THRESHOLD 256
> +#define NILFS_CLDCONFIG_MC_MIN_FREE_BLOCKS_THRESHOLD 128
Why 256 or 128? What is good? What is bad?
I am a user. How can I define what value is appropriate?
How should I think for choosing some value?
For example, I want to have the fastest performance as possible. How can I define
an appropriate value? Or, maybe, I want to clean as many segments as possible.
How should I think?
Or, maybe, I want combination of GC policies.
Thanks,
Vyacheslav Dubeyko.
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