From: Wei Liu <wei.liu@kernel.org>
To: Michael Kelley <mikelley@microsoft.com>
Cc: sthemmin@microsoft.com, kys@microsoft.com, wei.liu@kernel.org,
decui@microsoft.com, tglx@linutronix.de, mingo@redhat.com,
bp@alien8.de, x86@kernel.org, hpa@zytor.com, arnd@arndb.de,
linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org,
linux-arch@vger.kernel.org
Subject: Re: [PATCH 1/3] Drivers: hv: Make portions of Hyper-V init code be arch neutral
Date: Mon, 12 Jul 2021 18:40:47 +0000 [thread overview]
Message-ID: <20210712184047.cyrebl6orh5znmkk@liuwe-devbox-debian-v2> (raw)
In-Reply-To: <20210712182400.yze3wochnyccaflw@liuwe-devbox-debian-v2>
On Mon, Jul 12, 2021 at 06:24:00PM +0000, Wei Liu wrote:
> On Sun, Jul 11, 2021 at 08:25:14PM -0700, Michael Kelley wrote:
> [...]
> > +int hv_common_cpu_init(unsigned int cpu)
> > +{
> > + void **inputarg, **outputarg;
> > + u64 msr_vp_index;
> > + gfp_t flags;
> > + int pgcount = hv_root_partition ? 2 : 1;
> > +
> > + /* hv_cpu_init() can be called with IRQs disabled from hv_resume() */
> > + flags = irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL;
> > +
> > + inputarg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
> > + *inputarg = kmalloc(pgcount * HV_HYP_PAGE_SIZE, flags);
>
> This is changed from alloc_pages to kmalloc. Does it ensure the
> alignment is still correct?
kmalloc is rather complex and can be backed by either SLUB, SLAB or
SLOB, all of which differ from the others.
I _think_ for large allocations (> 1 native page) they tend to pass the
request on to the page allocator, but still there is a level of
indirection.
If the host page size is 64KiB, while the allocation is only 4KiB or
8KiB, could there be a chance that they become misaligned?
Wei.
>
> Wei.
next prev parent reply other threads:[~2021-07-12 18:40 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-12 3:25 [PATCH 0/3] Additional refactoring of Hyper-V arch specific code Michael Kelley
2021-07-12 3:25 ` [PATCH 1/3] Drivers: hv: Make portions of Hyper-V init code be arch neutral Michael Kelley
2021-07-12 18:24 ` Wei Liu
2021-07-12 18:40 ` Wei Liu [this message]
2021-07-12 18:41 ` Michael Kelley
2021-07-12 18:51 ` Wei Liu
2021-07-12 3:25 ` [PATCH 2/3] Drivers: hv: Add arch independent default functions for some Hyper-V handlers Michael Kelley
2021-07-12 3:25 ` [PATCH 3/3] Drivers: hv: Move Hyper-V misc functionality to arch-neutral code Michael Kelley
2021-07-14 9:37 ` [PATCH 0/3] Additional refactoring of Hyper-V arch specific code Wei Liu
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