task: reduce memory usage

[nokute78]

Refer to Valgrind, the size of flb_config is about 33KB.

$ valgrind --tool=massif bin/fluent-bit -i cpu -o stdout
.
$ ms_print massif.out.7631 
.
->55.89% (33,120B) 0x41334B: flb_config_init (in /home/taka/git/oss/pull_req/fluentbit_env/fluent-bit/build/bin/fluent-bit)
| ->55.89% (33,120B) 0x41092E: main (in /home/taka/git/oss/pull_req/fluentbit_env/fluent-bit/build/bin/fluent-bit)
.

It is caused by this member.

    struct flb_task_map tasks_map[2048];

flb_task_map is like this.

struct flb_task_map {
    uint8_t id;
    void    *task;
};

So, the size of array tasks_map is (8 + 8) *2048= 32.7KB.

By the way, the value id is used like bool.
So, I deleted id to reduce memory usage.

Signed-off-by: Takahiro YAMASHITA nokute78@gmail.com

[nokute78]

My patch reduces memory usage of flb_config. 33.1KB -> 16.7KB.

Before

$ ms_print massif.out.7631 
.
->55.89% (33,120B) 0x41334B: flb_config_init (in /home/taka/git/oss/pull_req/fluentbit_env/fluent-bit/build/bin/fluent-bit)
| ->55.89% (33,120B) 0x41092E: main (in /home/taka/git/oss/pull_req/fluentbit_env/fluent-bit/build/bin/fluent-bit)
.

After

99.24% (17,070B) (heap allocation functions) malloc/new/new[], --alloc-fns, etc.
->97.30% (16,736B) 0x41334B: flb_config_init (in /home/taka/git/oss/pull_req/fluentbit_env/fluent-bit/build/bin/fluent-bit)
| ->97.30% (16,736B) 0x41092E: main (in /home/taka/git/oss/pull_req/fluentbit_env/fluent-bit/build/bin/fluent-bit)

[edsiper]

thanks.