On Thu, Jan 18, 2024 at 05:35:04AM -0800, Yang Shi wrote: > It doesn't make too much sense to force huge page alignment on 32 bit > system due to the constrained virtual address space. > > [1] https://lore.kernel.org/linux-mm/CAHbLzkqa1SCBA10yjWTtA2mKCsoK5+M1BthSDL8ROvUq2XxZMw@xxxxxxxxxxxxxx/T/#mf211643a0427f8d6495b5b53f8132f453d60ab95 > [2] https://lore.kernel.org/linux-mm/CAHbLzkqa1SCBA10yjWTtA2mKCsoK5+M1BthSDL8ROvUq2XxZMw@xxxxxxxxxxxxxx/T/#me93dff2ccbd9902c3e395e1c022fb454e48ecb1d I feel sure there are shorter URLs for those messages ... > @@ -811,6 +812,14 @@ static unsigned long __thp_get_unmapped_area(struct file *filp, > loff_t off_align = round_up(off, size); > unsigned long len_pad, ret; > > + /* > + * It doesn't make too much sense to froce huge page alignment on > + * 32 bit system or compat userspace due to the contrained virtual > + * address space and address entropy. > + */ I honestly wouldn't even comment this. But if you must, /* Using THP alignment is not as important as address randomisation */ > + if (IS_ENABLED(CONFIG_32BIT) || in_compat_syscall()) > + return 0; > + > if (off_end <= off_align || (off_end - off_align) < size) > return 0; > > -- > 2.41.0 >
