Hi, Jeff Breidenbach: > Filenames are like "msg1234567.html" > > $ ls -U | wc > 1600415 1600415 24506508 > > I would like to have a safety margin of 2X, because this directory will gro= > w.
Ok. I tried ubuntu 2.6.24-24-server kernel on my test machine and begin thinking that the trigger of your problem MAY be memory fragmentation. Because you have installed plenty of RAM and the kernel log shows some bigger numbers as free pages, as long as those numbers are correct and SLUB in ubuntu kernel is fine, the fragmentation MAY be the cause (I may be wrong). In your last kernel log, it showed the memory allocation for 1MB failed. And now it failed 128KB allocation. It looks weird. Anyway, VDIR in aufs does not suit for such large directory, because VDIR builds dir blocks in memory which contain all entry names. It means that when you readdir(3) to that dir, aufs allocates more than 24MB memory in kernel space. Although the memory will be freed after several seconds later closedir(3), allocating such large memory in kernel space is not a good approach. I may be able to stop these messages by specifying the __GFP_NOWARN flag, but it doesn't solve the problem. the memory allocation failure will be still failure. Currently I have a plan to address your problem. - develop a new hook in user-space for readdir(3) as a shared object library. - the hook will issue a 'raw' readdir/getdents request to aufs, merge the result, and build VDIR in user space. - the raw request to aufs is equivalent to the direct readdir to the branch in aufs. - you can specify the hook per process. - you don't need to re-compile your binary, just specifying some environment variables. - the performance may be damaged, but the memory consumption in kernel space is much less. - in other words, move VDIR from kernel space to user space. How do you think? J. R. Okajima ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july
