Re: [RFC][PATCH 3/5] add /dev/mem_notify device

From: Randy Dunlap
Date: Mon Jan 14 2008 - 20:10:38 EST


On Tue, 15 Jan 2008 10:01:21 +0900 KOSAKI Motohiro wrote:

> the core of this patch series.
> add /dev/mem_notify device for notification low memory to user process.
>
> <usage examle>
>
> fd = open("/dev/mem_notify", O_RDONLY);
> if (fd < 0) {
> exit(1);
> }
> pollfds.fd = fd;
> pollfds.events = POLLIN;
> pollfds.revents = 0;
> err = poll(&pollfds, 1, -1); // wake up at low memory
>
> ...
> </usage example>
>
> Signed-off-by: Marcelo Tosatti <marcelo@xxxxxxxxx>
> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
>
> ---
> drivers/char/mem.c | 6 ++
> include/linux/mem_notify.h | 41 ++++++++++++++++
> include/linux/mmzone.h | 1
> mm/Makefile | 2
> mm/mem_notify.c | 109 +++++++++++++++++++++++++++++++++++++++++++++
> mm/page_alloc.c | 1
> 6 files changed, 159 insertions(+), 1 deletion(-)
>

Hi,

1/ I don't see the file below listed in the diffstat above...

2/ Where is the userspace interface information for the syscall?

> Index: linux-2.6.24-rc6-mm1-memnotify/Documentation/devices.txt
> ===================================================================
> --- linux-2.6.24-rc6-mm1-memnotify.orig/Documentation/devices.txt 2008-01-13 16:42:57.000000000 +0900
> +++ linux-2.6.24-rc6-mm1-memnotify/Documentation/devices.txt 2008-01-13 17:07:05.000000000 +0900
> @@ -96,6 +96,7 @@ Your cooperation is appreciated.
> 11 = /dev/kmsg Writes to this come out as printk's
> 12 = /dev/oldmem Used by crashdump kernels to access
> the memory of the kernel that crashed.
> + 13 = /dev/mem_notify Low memory notification.
>
> 1 block RAM disk
> 0 = /dev/ram0 First RAM disk


---
~Randy
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