fluent-bit: error initializing backend file(Cannot allocate memory)

Bug Report

Catch below error

[2019/01/18 11:28:15] [error] [storage] [cio chunk] error initializing backend file [2019/01/18 11:28:15] [error] [input chunk] could not create chunk file [2019/01/18 11:28:15] [error] [input chunk] no available chunk [lib/chunkio/src/cio_file.c:254 errno=12] Cannot allocate memory [2019/01/18 11:28:15] [error] [storage] cannot mmap file /var/log/fluent-bit//tail.1/145563-1547782095.129903982.flb

To Reproduce

1. storage.type=filesystem
2. run fluent-bit for a long time

Your Environment

• Version used: v1.0.1
• Configuration:

`

@INCLUDE input_*.conf
@SET DBFILE=/etc/fluent-bit/tailfile.db
[SERVICE]
    Flush        5
    Daemon       Off
    Log_Level    info
    HTTP_Server  Off
    storage.path /var/log/fluent-bit/
    storage.sync normal
    Parsers_File parser.conf

[OUTPUT]
    Name http
    Match *
    Host 127.0.0.1
    Port 56924
    URI /api/v1/logs
    Format json
    json_date_key time
    json_date_format iso8601
    Retry_Limit False

`

• Server type and version:
• Operating System and version: CentOS Linux release 7.4.1708 (Core)
• Filters and plugins:

`

[FILTER]
    Name grep
    Match *
    Regex name .+

input files

[INPUT]
    Name tail
    storage.type filesystem
    DB ${DBFILE}
    Path /var/log/xx/xxx.log
    Parser parse1

[INPUT]
    Name tail
    storage.type filesystem
    DB ${DBFILE}
    Path /var/log/yyy/yyy.log
    Parser parser2

`

thanks a lot