Re: Question about page allocation failure

["liyu@WAN" <liyu@ccoss.com.cn>]

the related code is here:

       /* This allocation should allow future memory freeing. */

       if (((p->flags & PF_MEMALLOC) || 
unlikely(test_thread_flag(TIF_MEMDIE)))
                       && !in_interrupt()) {
               if (!(gfp_mask & __GFP_NOMEMALLOC)) {
                       /* go through the zonelist yet again, ignoring 
mins */
                       for (i = 0; (z = zones[i]) != NULL; i++) {
                               if (!cpuset_zone_allowed(z))
                                       continue;
                               page = buffered_rmqueue(z, order, gfp_mask);
                               if (page)
                                       goto got_pg;
                       }
               }
               goto nopage;
       }

       /* Atomic allocations - we can't balance anything */
       if (!wait)
               goto nopage;
                                                                                                   

nopage:
       if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit()) {
               printk(KERN_WARNING "%s: page allocation failure."
                       " order:%d, mode:0x%x\n",
                       p->comm, order, gfp_mask);
               dump_stack();
       }
       return NULL;



if we are in normal case, there have two possbiles:
   1. total of memory  is too low.
   2. /* Atomic allocations - we can't balance anything */

I think this is not too dangerous.

PS: I use 2.6.12.

Any more clear idea?


sailor



nopage:
  
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