Messages in this thread | | | Date | Wed, 05 May 2010 21:35:17 +0530 | From | Nitin Gupta <> | Subject | Re: [PATCH 0/3] ramzswap: Eliminate stale data in compressed memory |
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On 05/05/2010 08:44 PM, Linus Torvalds wrote: > > > On Wed, 5 May 2010, Nitin Gupta wrote: >> >> ramzswap driver creates RAM based block devices which can be >> used (only) as swap disks. Pages swapped to these disks are >> compressed and stored in memory itself. > > Ok, this patch series looks way better, if only because it looks less > hacky. > > That said, I absolutely _hate_ the f*cking notifier model that takes > "type" flags. It's a disgrace. It's a horrible horrible model. >
You mean you didn't like the 'swap type' value passed around by notifier calls, as here: "blocking_notifier_call_chain(&swapon_notify_list, type, swap_file);" ?
> I'd much rather bind a nice "swap_operations" structure to the device, and > have that structure have function pointers for the different operations. > No stupid "operation type codes". Real, honest-to-goodness function > pointers. >
I think such 'swap_operations' structure will be have to be part of block_device_operations, so we may access it from swap_entry_free() where a swap slot is freed. This will also get rid of all this notifier stuff.
The patch you nacked did something similar: it add 'swap_slot_free_callback' directly to block_device_operations. Without such change, I could not think of any way to do away with notifiers.
> The notifier layer is a total piece of sh*t. I'm sorry I ever merged it, > and I'm _doubly_ sorry that it's use is so horribly widespread. It's a > mistake.
Thanks, Nitin
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