On Mon, 2007-08-20 at 11:38 +1000, Nigel Cunningham wrote: > Hi all. > > In current git (and for a while now), an attempt to allocate memory with > GFP_ATOMIC will fail if we're below the low watermark level. The only way to > access that memory that I can see (not that I've looked that hard) is to have > PF_MEMALLOC set (ie from kswapd). I'm wondering if this behaviour is correct. > Shouldn't GFP_ATOMIC allocations ignore watermarks too? How about GFP_KERNEL? > > The following patch is a potential fix for GFP_ATOMIC.
Sorry, no. GFP_ATOMIC must fail when below the watermark. GFP_KERNEL has __GFP_WAIT and hence can sleep and wait for reclaim so that should not be a problem (usually). GFP_ATOMIC may not access the reserves because the reserves are needed to get out of OOM deadlocks within the VM. Consider the fact that freeing memory needs memory - if there is no memory free, you cannot free memory and you're pretty much stuck. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
