Re: [PATCH 0/3] ramzswap: Eliminate stale data from compressed memory (v2 resend)
From: Pekka Enberg
Date: Mon May 17 2010 - 02:10:47 EST
On Mon, May 17, 2010 at 8:32 AM, Nitin Gupta <ngupta@xxxxxxxxxx> wrote:
> Resending as Greg wanted.
>
> (tested on mainline but should apply to linux-next cleanly)
>
>
> * Changelog: v2 vs initial patches
> - directly add swap free callback to block_device_operations
> instead of using 'notifiers' for various swap events.
>
> 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.
>
> However, these devices do not get any notification when a swap
> slot is freed (swap_map[i] reaches 0). So, we cannot free memory
> allocated corresponding to this swap slot. Such stale data can
> quickly accumulate in (compressed) memory defeating the whole
> purpose of such devices.
>
> To overcome this problem, we now add a callback in struct
> block_device_operations which is called as soon as a swap
> slot is freed.
>
> Nitin Gupta (3):
> Add flag to identify block swap devices
> Add swap slot free callback to block_device_operations
> ramzswap: Handler for swap slot free callback
>
> drivers/staging/ramzswap/TODO | 5 -----
> drivers/staging/ramzswap/ramzswap_drv.c | 22 +++++++++++++---------
> include/linux/blkdev.h | 2 ++
> include/linux/swap.h | 1 +
> mm/swapfile.c | 5 +++++
> 5 files changed, 21 insertions(+), 14 deletions(-)
> delete mode 100644 drivers/staging/ramzswap/TODO
Nitin, please retain ACKs when resending patches.
Acked-by: Pekka Enberg <penberg@xxxxxxxxxxxxxx>
for the whole series.
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