On Sun, Feb 25, 2024 at 09:13:47AM +1300, Thomas Munro wrote: > On Sun, Feb 25, 2024 at 9:12 AM Thomas Munro <thomas.mu...@gmail.com> wrote: > > On Sun, Feb 25, 2024 at 8:50 AM Noah Misch <n...@leadboat.com> wrote: > > > On GNU/Linux x64, gcc correctly records alignment=2**12 for the associated > > > section (.rodata for bulk_write.o zero_buffer, .bss for pg_prewarm.o > > > blockbuffer). If I'm reading this right, neither AIX gcc nor xlc is > > > marking > > > the section with sufficient alignment, in bulk_write.o or pg_prewarm.o: > > > > Ah, that is a bit of a hazard that we should probably document. > > > > I guess the ideas to fix this would be: use smgrzeroextend() instead > > of this coding, and/or perhaps look at the coding of pg_pwrite_zeros() > > (function-local static) for any other place that needs such a thing, > > if it would be satisfied by function-local scope?
True. Alternatively, could arrange for "#define PG_O_DIRECT 0" on AIX, which disables the alignment assertions (and debug_io_direct). > Erm, wait, how does that function-local static object work differently? I don't know specifically, but I expect they're different parts of the gcc implementation. Aligning an xcoff section may entail some xcoff-specific gcc component. Aligning a function-local object just changes the early instructions of the function; it's independent of the object format.
