On Thu, 9 Nov 2023 21:15:07 +0000 "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> wrote: > GFP_NOWAIT callers are always prepared for their allocations to fail > because they fail so frequently. Forcing the callers to remember to add > __GFP_NOWARN is just annoying and leads to an endless stream of patches > for the places where we forgot to add it. A possible problem is call sites where the developers were relying upon the core MM's warning, so they chose to omit __GFP_NOWARN rather than adding a local printk. We're now silencing core MM's warning so those developers might lose some diagnostic information. Random example, arch/s390/pci/pci_clp.c:clp_refresh_fh(). After this change, the pci_clp developers won't see (or be told about) allocation failures in this function. If they know about this change, they may now choose to add a local printk. It's not the end of the world by any means. One possible way to prevent this change in behavior is to add a new __GFP_WARN and go add it to all the sites which use bare __GFP_NOWAIT and which do not have a local printk for the allocation failure.
