On Fri, 10 Jun 2011, Russell King - ARM Linux wrote: > > > > Should one submit a patch adding a warning to GFP_DMA allocations > > > > w/o ZONE_DMA, or the idea of the original patch is wrong? > > > > > > Linus was far from impressed by the original commit, saying: > > > | Using GFP_DMA is reasonable in a driver - on platforms where that > > > | matters, it should allocate from the DMA zone, on platforms where it > > > | doesn't matter it should be a no-op. > > > > > > So no, not even a warning. > > > > > > > Any words of wisdom for users with CONFIG_ZONE_DMA=n that actually use > > drivers where they need GFP_DMA? The page allocator should just silently > > return memory from anywhere? > > See Linus' reply. I quote again "on platforms where it doesn't matter it > should be a no-op". If _you_ have a problem with that _you_ need to > discuss it with _Linus_, not me. I'm not going to be a middle-man sitting > between two people with different opinions. > We're talking about two different things. Linus is saying that if GFP_DMA should be a no-op if the hardware doesn't require DMA memory because the kernel was correctly compiled without CONFIG_ZONE_DMA. I'm asking about a kernel that was incorrectly compiled without CONFIG_ZONE_DMA and now we're returning memory from anywhere even though we actually require GFP_DMA. If you don't want to form an opinion of your own, then I have no problem cc'ing Linus on it. I don't think he'd object to a #ifndef CONFIG_ZONE_DMA WARN_ON_ONCE(1, "%s (%d): allocating DMA memory without DMA support -- " "enable CONFIG_ZONE_DMA if needed.\n", current->comm, current->pid); #endif -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>