Messages in this thread | | | Date | Wed, 24 Jun 2009 12:46:02 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: upcoming kerneloops.org item: get_page_from_freelist |
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On Wed, 24 Jun 2009, Andrew Morton wrote:
> On Wed, 24 Jun 2009 12:16:20 -0700 (PDT) > Linus Torvalds <torvalds@linux-foundation.org> wrote: > > > Lookie here. This is 2.6.0:mm/page_alloc.c: > > > > do_retry = 0; > > if (!(gfp_mask & __GFP_NORETRY)) { > > if ((order <= 3) || (gfp_mask & __GFP_REPEAT)) > > do_retry = 1; > > if (gfp_mask & __GFP_NOFAIL) > > do_retry = 1; > > } > > if (do_retry) { > > blk_congestion_wait(WRITE, HZ/50); > > goto rebalance; > > } > > rebalance: > if ((p->flags & (PF_MEMALLOC | PF_MEMDIE)) && !in_interrupt()) { > /* go through the zonelist yet again, ignoring mins */ > for (i = 0; zones[i] != NULL; i++) { > struct zone *z = zones[i]; > > page = buffered_rmqueue(z, order, cold); > if (page) > goto got_pg; > } > goto nopage; > }
Your point?
That's the recursive allocation or oom case. Not the normal case at all.
The _normal_ case is to do the whole "try_to_free_pages()" case and try and try again. Forever.
IOW, we have traditionally never failed small kernel allocations. It makes perfect sense that people _depend_ on that.
Now, we have since relaxed that (a lot). And in answer to that, people have added more __GFP_NOFAIL flags, I bet. It's all very natural. Claiming that this is some "new error" and that we should warn about NOFAIL allocations with big orders is just silly and simply not true.
Linus
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