On Tue, Jun 02, 2020 at 09:23:57PM +1000, Michael Ellerman wrote: > Markus Elfring <Markus.Elfring@xxxxxx> writes: > >>>> Please just remove the message instead, it's a tiny allocation that's > >>>> unlikely to ever fail, and the caller will print an error anyway. > >>> > >>> How do you think about to take another look at a previous update suggestion > >>> like the following? > >>> > >>> powerpc/nvram: Delete three error messages for a failed memory allocation > >>> https://patchwork.ozlabs.org/project/linuxppc-dev/patch/00845261-8528-d011-d3b8-e9355a231d3a@xxxxxxxxxxxxxxxxxxxxx/ > >>> https://lore.kernel.org/linuxppc-dev/00845261-8528-d011-d3b8-e9355a231d3a@xxxxxxxxxxxxxxxxxxxxx/ > >>> https://lore.kernel.org/patchwork/patch/752720/ > >>> https://lkml.org/lkml/2017/1/19/537 > >> > >> That deleted the messages from nvram_scan_partitions(), but neither of > >> the callers of nvram_scan_paritions() check its return value or print > >> anything if it fails. So removing those messages would make those > >> failures silent which is not what we want. > > > > * How do you think about information like the following? > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/coding-style.rst?id=f359287765c04711ff54fbd11645271d8e5ff763#n883 > > “… > > These generic allocation functions all emit a stack dump on failure when used > > without __GFP_NOWARN so there is no use in emitting an additional failure > > message when NULL is returned. > > …” > > Are you sure that's actually true? > > A quick look around in slub.c leads me to: > > slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid) > { > #ifdef CONFIG_SLUB_DEBUG You first have to enable EXPERT mode before you can disable SLUB_DEBUG. So that hopefully means you *really* want to save memory. It doesn't make sense to add a bunch of memory wasting printks when the users want to go to extra lengths to conserve memory. regards, dan carpenter
