Re: [RFC] per thread page reservation patch

[Hugh Dickins]

On Sat, 8 Jan 2005, Nikita Danilov wrote:
> Andrew Morton <akpm@xxxxxxxx> writes:
> >
> > __alloc_pages(GFP_KERNEL, ...) doesn't return NULL.  It'll either succeed
> > or never return ;) That behaviour may change at any time of course, but it
> 
> Hmm... it used to, when I wrote that code.

And still does, if OOM decides to kill _your_ task: OOM sets PF_MEMDIE,
and then you don't get to go the retry route at all:

	/* This allocation should allow future memory freeing. */
	if ((p->flags & (PF_MEMALLOC | PF_MEMDIE)) && !in_interrupt()) {
		/* go through the zonelist yet again, ignoring mins */
		for (i = 0; (z = zones[i]) != NULL; i++) {
			page = buffered_rmqueue(z, order, gfp_mask);
			if (page)
				goto got_pg;
		}
		goto nopage;
	}
....
nopage:
	....
	return NULL;

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