Emacs eats up my memory while viewing images

Emacs eats up my memory while viewing images

[Danny YUE]

Hi guys,

I was viewing some (well, lots of) old images using image+ in Emacs.
Then I noticed that it opens new image slower and slower.
I ran command `free -h` and noticed that my memory was almost totally
consumed.
Then I killed Emacs and memory consumption dropped to normal level.

I suspect there is something wrong with it, because when I press "N" for
`image-next-file`, the old image file is removed from buffer list, thus
the memory consumed by it *should* be released...

Any help is appreciated.

Danny

Re: Emacs eats up my memory while viewing images

[Alexis]

Danny YUE <sheepduke@gmail.com> writes:

> I suspect there is something wrong with it, because when I press 
> "N"
> for `image-next-file`, the old image file is removed from buffer 
> list,
> thus the memory consumed by it *should* be released...

Not necessarily; it depends on the OS. Some only mark memory as
again available after the application exits. What OS are you 
running
Emacs on?


Alexis.

Re: Emacs eats up my memory while viewing images

[Eli Zaretskii]

> From: Danny YUE <sheepduke@gmail.com>
> Date: Thu, 08 Jun 2017 19:58:03 +0800
> 
> I was viewing some (well, lots of) old images using image+ in Emacs.
> Then I noticed that it opens new image slower and slower.
> I ran command `free -h` and noticed that my memory was almost totally
> consumed.
> Then I killed Emacs and memory consumption dropped to normal level.
> 
> I suspect there is something wrong with it, because when I press "N" for
> `image-next-file`, the old image file is removed from buffer list, thus
> the memory consumed by it *should* be released...

The memory isn't released immediately because Emacs caches images for
better performance.  And even if Emacs does free the memory used for
the image and its buffer, it doesn't necessarily return that memory to
the OS; that depend on the build and the OS you are using.

Try the command "M-x clear-image-cache".  If that helps, you may wish
to customize your value of image-cache-eviction-delay.

Re: Emacs eats up my memory while viewing images

[Danny YUE]

On 2017-06-08 14:54, Alexis <flexibeast@gmail.com> wrote:
> Danny YUE <sheepduke@gmail.com> writes:
>
>> I suspect there is something wrong with it, because when I press
>> "N"
>> for `image-next-file`, the old image file is removed from buffer
>> list,
>> thus the memory consumed by it *should* be released...
>
> Not necessarily; it depends on the OS. Some only mark memory as
> again available after the application exits. What OS are you
> running
> Emacs on?
>
>
> Alexis.

I am running Emacs on a Gentoo system.
Well, customized kernel, hard to say.

I forgot to mention that more than 1 GB (out of 8GB) memory was released
after I killed Emacs. Is that really *normal*?

But thanks, you inspired me ;-)

Danny

Re: Emacs eats up my memory while viewing images

[Danny YUE]

On 2017-06-08 15:09, Eli Zaretskii <eliz@gnu.org> wrote:
>> From: Danny YUE <sheepduke@gmail.com>
>> Date: Thu, 08 Jun 2017 19:58:03 +0800
>> 
>> I was viewing some (well, lots of) old images using image+ in Emacs.
>> Then I noticed that it opens new image slower and slower.
>> I ran command `free -h` and noticed that my memory was almost totally
>> consumed.
>> Then I killed Emacs and memory consumption dropped to normal level.
>> 
>> I suspect there is something wrong with it, because when I press "N" for
>> `image-next-file`, the old image file is removed from buffer list, thus
>> the memory consumed by it *should* be released...
>
> The memory isn't released immediately because Emacs caches images for
> better performance.  And even if Emacs does free the memory used for
> the image and its buffer, it doesn't necessarily return that memory to
> the OS; that depend on the build and the OS you are using.
>
> Try the command "M-x clear-image-cache".  If that helps, you may wish
> to customize your value of image-cache-eviction-delay.

In fact `clear-image-cache` is not really an interactive command, it is
a function.

The current value of `image-cache-eviction-delay` is 300.
I will try to set it to a smaller value and have a try.

Thanks.

Danny

Re: Emacs eats up my memory while viewing images

[Eli Zaretskii]

> From: Danny YUE <sheepduke@gmail.com>
> Cc: help-gnu-emacs@gnu.org
> Date: Fri, 09 Jun 2017 00:06:49 +0800
> 
> > Try the command "M-x clear-image-cache".  If that helps, you may wish
> > to customize your value of image-cache-eviction-delay.
> 
> In fact `clear-image-cache` is not really an interactive command, it is
> a function.

Oops, you are right.  Sorry.  In any case, you can invoke it via
"M-:", to see if that helps.