Re: [patch] oom-5

Andrea Arcangeli (andrea@e-mind.com)
Wed, 7 Oct 1998 15:12:33 +0200 (CEST)


On Wed, 7 Oct 1998, Rik van Riel wrote:

>should push this into the main kernel right now, IMHO.
>Code cleanup is always a good thing...
>
>> if (gfp_mask & __GFP_WAIT)
>> + {
>
>Just one problem... Hardly anybody uses __GFP_WAIT anymore,

???

#define GFP_KERNEL (__GFP_MED | __GFP_WAIT)

>instead, we let the I/O requests accumulate till we have a
>nice amount and then we flush it. Maybe we want to decide
>this with a flag (agressive) to try_to_free_pages?

I don' t worry too much about swapout performance here. I only care that
everything works fine right now...

>> /*
>> + * If we can' t free one page we can' t able to
>> + * free tries page. -arca
>> + */
>> + if (!do_try_to_free_page(0))
>> + break;
>
>As I pointed out, this is plain wrong in a lot of
>situations. It might work on your machine, but it
>definately will fail on a lot of other machines.
>This is about the only piece of the patch that I
>have real problems with...

OK, thanks for your comment.

As first thing I have to say that I can live with a kernel that segfault
too early a leak-malicious-proggy but I can' t with a kernel that deadlock
if I run the same malicious proggy.

As second I can' t reproduce the problem you are reporting here (at least
with oom-5). Could you tell me a way to reproduce it to allow me to tune
things better?

And BTW, my patch still need some other _minor_ improvement, like waking
up kswapd after a process exit() if we are low in memory (I got this idea
this morning while studying Analysis ;-).

Andrea[s] Arcangeli

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