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    DateTue, 31 Jan 2006 23:42:00 -0800
    FromHans Reiser <>
    SubjectRe: Recursive chmod/chown OOM kills box with 32MB RAM
    Denis Vlasenko wrote:
    
    >On Monday 30 January 2006 15:22, Chris Mason wrote:
    > 
    >
    >>On Monday 30 January 2006 01:11, Hans Reiser wrote:
    >> 
    >>
    >>>Chris, would Denis Vlasenko wrote:
    >>> 
    >>>
    >>>>[CCing namesys]
    >>>>
    >>>>Narrowed it down to 100% reproducible case:
    >>>>
    >>>>	chown -Rc 0:<n> .
    >>>>
    >>>>in a top directory of tree containing ~21938 files
    >>>>on reiser3 partition:
    >>>>
    >>>>	/dev/sdc3 on /.3 type reiserfs (rw,noatime)
    >>>>
    >>>>causes oom kill storm. "ls -lR", "find ." etc work fine.
    >>>>
    >>>>I suspected that it is a leak in winbindd libnss module,
    >>>>but chown does not seem to grow larger in top, and also
    >>>>running it under softlimit -m 400000 still causes oom kills
    >>>>while chown's RSS stays below 4MB.
    >>>> 
    >>>>
    >>In order for the journaled filesystems to make sure the FS is consistent after 
    >>a crash, we need to keep some blocks in memory until other blocks have been 
    >>written.  These blocks are pinned, and can't be freed until a certain amount 
    >>of io is done.
    >>
    >>In the case of reiserfs, it might pin as much as the size of the journal at 
    >>any time.  The default journal is 32MB, which is much too large for a system 
    >>with only 32MB of ram.
    >>
    >>You can shrink the log of an existing filesystem.  The minimum size is 513 
    >>blocks, you might try 1024 as a good starting poing.
    >>
    >>reiserfstune -s 1024 /dev/xxxx
    >>
    >>The filesystem must be unmounted first.
    >> 
    >>
    >
    >Will try this and report the result.
    >
    >Please consider printing a big fat warning at mount time if total RAM
    >on the system is close to sum of RAM space required for all currently
    >mounted reiserfs partitions...
    >--
    >vda
    >
    >
    > 
    >
    I already suggested this to Chris.;-)  I agree.
    
    Best,
    
    Hans
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