On Mon, Feb 15, 2010 at 11:41:49PM -0800, David Rientjes wrote: > On Tue, 16 Feb 2010, Nick Piggin wrote: > > > > As I already explained when you first brought this up, the possibility of > > > not invoking the oom killer is not unique to GFP_DMA, it is also possible > > > for GFP_NOFS. Since __GFP_NOFAIL is deprecated and there are no current > > > users of GFP_DMA | __GFP_NOFAIL, that warning is completely unnecessary. > > > We're not adding any additional __GFP_NOFAIL allocations. > > > > Completely agree with this request. Actually, I think even better you > > should just add && !(gfp_mask & __GFP_NOFAIL). Deprecated doesn't mean > > it is OK to break the API (callers *will* oops or corrupt memory if > > __GFP_NOFAIL returns NULL). > > > > ... unless it's used with GFP_ATOMIC, which we've always returned NULL > for when even ALLOC_HARDER can't find pages, right? Ye, it's never worked with GFP_ATOMIC. > I'm wondering where this strong argument in favor of continuing to support > __GFP_NOFAIL was when I insisted we call the oom killer for them even for > allocations over PAGE_ALLOC_COSTLY_ORDER when __alloc_pages_nodemask() was > refactored back in 2.6.31. The argument was that nobody is allocating > that high of orders of __GFP_NOFAIL pages so we don't need to free memory > for them and that's where the deprecation of the modifier happened in the > first place. Ultimately, we did invoke the oom killer for those > allocations because there's no chance of forward progress otherwise and, > unlike __GFP_DMA, GFP_KERNEL | __GFP_NOFAIL actually is popular. I don't know. IMO we should never just randomly weaken or break such flag as the page allocator API. > > I'll add this check to __alloc_pages_may_oom() for the !(gfp_mask & > __GFP_NOFAIL) path since we're all content with endlessly looping. Thanks. Yes endlessly looping is far preferable to randomly oopsing or corrupting memory. -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>