JFFS2 Garbage collection issue

[Albrecht, Harald]

Hi All,

thank you for the fast reply.
What we figured out is that the jffs2_garbage_collect_pass loops for 
several minutes in the first for(;;) loop. It always went into the if 
statement after jffs2_get_ino_cache. In this situation it's not 
interruptable by any signals.

Regards
   Harald


"linux-mtd" <linux-mtd-bounces at lists.infradead.org> wrote on 2013/11/27 
11:11:04:
>> Hi all,
>>
>> we are currently facing a problem with the Garbage-collection on a JFFS2
>> file system.
>>
>> We have an embedded linux system based on an ARM9 AT91RM9200 processor
>> with an Intel / Micron JS28F256 NOR-flash of 32MB in size.
>> The Flash holds the U-Boot loader and its environment and in the main
>> part (30MB) of the chip a JFFS2-based root-file-system.
>> Our Linux kernel version is 2.6.24.3
>>
>> Some minutes after startup of the system, the garbage collector (gc.c)
>> does a scan of the file system, gathering information for the garbage
>> collection procedures that may be initiated based upon that data.
>> On some file systems, especially such with long runtime and therefore
>> many file operations, this scan consumes a lot of time. On some systems
>> it stays in that scan for more that 10 minutes. The problem with this
>> behaviour is the fact, that during the scan the file system is locked,
>> and therefore all file operations are suspended. This leads to a crash
>> of the system, when the application program hangs for a long time,
>> waiting for a file operation to return from a system call, and the
>> watchdog is not triggered.
>>
>> In a test system without watchdog, after the scan, the system runs
> normally.
>> The flash chip itself shows no errors, so it seems to be a problem of
>> the file system.
>>
>> Any idea or suggestion to solve the problem would be very welcome!
> The simple fix is to send a signal(SIGCONT?) to the GC process regularly
> to do GC
> over time. That way you don't get all GC at boot time.
>
>   Jocke
>   
>
>
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