From: Linus Torvalds <torvalds@linux-foundation.org>
To: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
intel-gfx <intel-gfx@lists.freedesktop.org>,
Linux-MM <linux-mm@kvack.org>, Pavel Machek <pavel@ucw.cz>,
Andrew Morton <akpm@linux-foundation.org>,
Joerg Roedel <jroedel@suse.de>, Dave Airlie <airlied@redhat.com>,
Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
Rodrigo Vivi <rodrigo.vivi@intel.com>,
stable <stable@vger.kernel.org>
Subject: Re: [PATCH 2/4] drm/i915/gem: Sync the vmap PTEs upon construction
Date: Fri, 21 Aug 2020 05:41:03 -0700 [thread overview]
Message-ID: <CAHk-=wiu1WHD0x0VXKoLQGy43S7KLCY=Yd-TPDh=7tDW08554w@mail.gmail.com> (raw)
In-Reply-To: <20200821085011.28878-2-chris@chris-wilson.co.uk>
On Fri, Aug 21, 2020 at 1:50 AM Chris Wilson <chris@chris-wilson.co.uk> wrote:
>
> Since synchronising the PTE after assignment is a manual step, use the
> newly exported interface to flush the PTE after assigning via
> alloc_vm_area().
This commit message doesn't make much sense to me.
Are you talking about synchronizing the page directory structure
across processes after possibly creating new kernel page tables?
Because that has nothing to do with the PTE. It's all about making
sure the _upper_ layers of the page directories are populated
everywhere..
The name seems off to me too - what are you "flushing"? (And yes, I
know about the flush_cache_vmap(), but that looks just bogus, since
any non-mapped area shouldn't have any virtual caches to begin with,
so I suspect that is just the crazy architectures being confused -
flush_cache_vmap() is a no-op on any sane architecture - and powerpc
that mis-uses it for other things).
Linus
next prev parent reply other threads:[~2020-08-21 12:41 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-21 8:50 [PATCH 1/4] mm: Export flush_vm_area() to sync the PTEs upon construction Chris Wilson
2020-08-21 8:50 ` [PATCH 2/4] drm/i915/gem: Sync the vmap " Chris Wilson
2020-08-21 12:41 ` Linus Torvalds [this message]
2020-08-21 13:01 ` Chris Wilson
2020-08-21 8:50 ` [PATCH 3/4] drm/i915/gem: Use set_pte_at() for assigning the vmapped PTE Chris Wilson
2020-08-21 8:50 ` [PATCH 4/4] drm/i915/gem: Replace reloc chain with terminator on error unwind Chris Wilson
2020-08-21 9:51 ` [PATCH 1/4] mm: Export flush_vm_area() to sync the PTEs upon construction Joerg Roedel
2020-08-21 9:54 ` Chris Wilson
2020-08-21 10:22 ` Joerg Roedel
2020-08-21 10:36 ` Chris Wilson
2020-08-21 10:09 ` [PATCH] mm: Track page table modifications in __apply_to_page_range() construction Joerg Roedel
2020-08-21 10:13 ` Chris Wilson
2020-08-21 10:23 ` Joerg Roedel
2020-08-21 10:39 ` Chris Wilson
2020-08-21 11:38 ` Chris Wilson
2020-08-21 12:18 ` Joerg Roedel
2020-08-21 10:53 ` Greg KH
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