Messages in this thread | | | Date | Wed, 17 Nov 2004 13:38:36 +0200 | From | Jari Ruusu <> | Subject | Re: vm-pageout-throttling.patch: hanging in throttle_vm_writeout/blk_congestion_wait |
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Sami Farin wrote: > On Mon, Nov 15, 2004 at 09:56:29PM +0000, Hugh Dickins wrote: > > On Mon, 15 Nov 2004, Sami Farin wrote: > > > > > > this time I had some swapspace on /dev/loop1 (file-backed, reiserfs, > > > loop-AES-2.2d)... I think (!) it caused this deadlock. > > > > That's not at all surprising. See the swap_extent work Andrew did > > for 2.5 (in mm/swapfile.c), by which swap to a swapfile now avoids > > the filesystem altogether (except while swapon prepares the map of > > disk blocks). By swapping to a loop device over a file, you're > > sneaking past his work, and putting the filesystem back under swap. > > Aha... interesting. > > > It is begging for deadlocks: I'm not saying it couldn't be got to > > work, and of course it would be nice to boast that there's no such > > issue; but there are so many better places to invest such effort... > > So, this was a known issue and it's hard to fix? I didn't know that. > > I know it's a "nicer" idea to use some partition for the swap > instead of a file on reiserfs, but I created too small swap partitions > originally and I can't(/bother?) resize the other partitions. > And sometimes some memhog forces me to add even more swap.
Quote from loop-AES' README file: " 7.1. Example 1 - Encrypting swap on 2.4 and newer kernels ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Device backed (partition backed) loop is capable of encrypting swap on 2.4 and newer kernels. File backed loops can't be used for swap. "
That "file backed loops can't be used for swap" warning has been there in that README file since September 2001.
-- Jari Ruusu 1024R/3A220F51 5B 4B F9 BB D3 3F 52 E9 DB 1D EB E3 24 0E A9 DD - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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