From: Kameron Carr <[email protected]> Sent: Monday, August 3, 2026 10:40 AM > > On Saturday, August 1, 2026 9:17 PM, Michael Kelley wrote: > > From: Kameron Carr <[email protected]> Sent: Friday, July 31, > > 2026 12:06 PM > > > > > > On Friday, July 24, 2026 12:37 PM, Michael Kelley wrote: > > > > From: Kameron Carr <[email protected]> Sent: Tuesday, > > > > July 21, 2026 12:57 PM > > > [...] > > > > > + /* > > > > > + * @order monotonically decreases across iterations > > > > > + * > > > > > + * Use __GFP_NORETRY | __GFP_NOWARN to avoid OOM-killing, but > > > > > try > > > > > + * harder at order 0 since that is the final fallback. > > > > > + */ > > > > > + order = min_t(unsigned int, MAX_PAGE_ORDER, ilog2(nr_pages)); > > > > > > > > Prefer using min() instead of min_t(). For normal integer values, > > > > min() should work correctly. > > > > > > Using min() compiled fine on ARM, but x86 is throwing a compile error. > > > > > > drivers/hv/channel.c: In function 'vmbus_alloc_buffer': > > > ././include/linux/compiler_types.h:699:45: error: call to > > > '__compiletime_assert_518' declared with attribute error: min(order, > ( > > > __builtin_constant_p(remaining) ? ((remaining) < 2 ? 0 : 63 - > > > __builtin_clzll(remaining)) : (sizeof(remaining) <= 4) ? > > > __ilog2_u32(remaining) : __ilog2_u64(remaining) )) signedness error > > > > > > In my v3 I may go back to using min_t. Please let me know if a cast (or > > > some other method) is preferred. > > > > Hmmm. I don't get the same compile error on x86/x64. Maybe it is > > related to compiler and version, or the kernel code base against which > > the patch is being built. Probably you didn't see a problem on arm64 > > because of some such difference. FWIW, I built with gcc 11.4.0 against > > linux-next20260726. What is the compiler and base kernel info where > > you saw the error and on arm64 where you didn't? > > In both cases, I built against hyperv-next (a4ffc59). > On ARM64 I used gcc 13.2.0; on x86 I used 13.3.0. > > To do a fair comparison, I > * downgraded my x86 environment to gcc 13.2.0 > * started with `make defconfig` > * enabled Hyper-V and NetVSC in the config (=y) > > I saw the same behavior where there was no error on ARM and compile failure > on x86. >
Really weird. I compiled on x86/x64 with gcc 13.3.0, and saw no problem. This was against the official 7.1.0 release source code. Then I grabbed hyperv-next (the tag "hyperv-next-signed-20260621" specifically), added your patches, and again using gcc 13.3.0 I built with no problem. Are you using the same local copy of the source code for arm64 and x86/x64 builds? If not, I wonder if your local x86/x64 source code tree is somehow corrupt or not what you think it is. My .config file is different from yours. I did not try starting fresh with make defconfig and then enable Hyper-V and netvsc. Michael
