From: Matthew Wilcox <willy@infradead.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Jani Nikula <jani.nikula@linux.intel.com>,
Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
Rodrigo Vivi <rodrigo.vivi@intel.com>,
Minchan Kim <minchan@kernel.org>, Nitin Gupta <ngupta@vflare.org>,
x86@kernel.org, xen-devel@lists.xenproject.org,
linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org,
dri-devel@lists.freedesktop.org, linux-mm@kvack.org
Subject: Re: [PATCH 3/6] drm/i915: use vmap in shmem_pin_map
Date: Tue, 22 Sep 2020 15:53:23 +0100 [thread overview]
Message-ID: <20200922145323.GG32101@casper.infradead.org> (raw)
In-Reply-To: <20200922143906.GB26664@lst.de>
On Tue, Sep 22, 2020 at 04:39:06PM +0200, Christoph Hellwig wrote:
> On Tue, Sep 22, 2020 at 12:21:44PM +0100, Matthew Wilcox wrote:
> > Actually, vfree() will work today; I cc'd you on a documentation update
> > to make it clear that this is permitted.
>
> vfree calls __free_pages, the i915 and a lot of other code calls
> put_page. They are mostly the same, but not quite and everytime I
> look into that mess I'm more confused than before.
>
> Can someone in the know write sensible documentation on when to use
> __free_page(s) vs put_page?
I started on that, and then I found a bug that's been lurking for 12
years, so that delayed the documentation somewhat. The short answer is
that __free_pages() lets you free non-compound high-order pages while
put_page() can only free order-0 and compound pages.
I would really like to overhaul our memory allocation APIs:
current new
__get_free_page(s) alloc_page(s)
free_page(s) free_page(s)
alloc_page(s) get_free_page(s)
__free_pages put_page_order
Then put_page() and put_page_order() are more obviously friends.
But I cannot imagine a world in which Linus says yes to that upheaval.
He's previous expressed dislike of the get_free_page() family of APIs,
and thinks all those callers should just use kmalloc(). Maybe we can
make that transition happen, now that kmalloc() aligns larger allocations.
WARNING: multiple messages have this Message-ID (diff)
From: Matthew Wilcox <willy@infradead.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Juergen Gross <jgross@suse.com>,
Stefano Stabellini <sstabellini@kernel.org>,
linux-mm@kvack.org, Peter Zijlstra <peterz@infradead.org>,
intel-gfx@lists.freedesktop.org, x86@kernel.org,
linux-kernel@vger.kernel.org, Minchan Kim <minchan@kernel.org>,
dri-devel@lists.freedesktop.org,
Rodrigo Vivi <rodrigo.vivi@intel.com>,
xen-devel@lists.xenproject.org,
Andrew Morton <akpm@linux-foundation.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Nitin Gupta <ngupta@vflare.org>
Subject: Re: [PATCH 3/6] drm/i915: use vmap in shmem_pin_map
Date: Tue, 22 Sep 2020 15:53:23 +0100 [thread overview]
Message-ID: <20200922145323.GG32101@casper.infradead.org> (raw)
In-Reply-To: <20200922143906.GB26664@lst.de>
On Tue, Sep 22, 2020 at 04:39:06PM +0200, Christoph Hellwig wrote:
> On Tue, Sep 22, 2020 at 12:21:44PM +0100, Matthew Wilcox wrote:
> > Actually, vfree() will work today; I cc'd you on a documentation update
> > to make it clear that this is permitted.
>
> vfree calls __free_pages, the i915 and a lot of other code calls
> put_page. They are mostly the same, but not quite and everytime I
> look into that mess I'm more confused than before.
>
> Can someone in the know write sensible documentation on when to use
> __free_page(s) vs put_page?
I started on that, and then I found a bug that's been lurking for 12
years, so that delayed the documentation somewhat. The short answer is
that __free_pages() lets you free non-compound high-order pages while
put_page() can only free order-0 and compound pages.
I would really like to overhaul our memory allocation APIs:
current new
__get_free_page(s) alloc_page(s)
free_page(s) free_page(s)
alloc_page(s) get_free_page(s)
__free_pages put_page_order
Then put_page() and put_page_order() are more obviously friends.
But I cannot imagine a world in which Linus says yes to that upheaval.
He's previous expressed dislike of the get_free_page() family of APIs,
and thinks all those callers should just use kmalloc(). Maybe we can
make that transition happen, now that kmalloc() aligns larger allocations.
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
WARNING: multiple messages have this Message-ID (diff)
From: Matthew Wilcox <willy@infradead.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Juergen Gross <jgross@suse.com>,
Stefano Stabellini <sstabellini@kernel.org>,
linux-mm@kvack.org, Peter Zijlstra <peterz@infradead.org>,
intel-gfx@lists.freedesktop.org, x86@kernel.org,
linux-kernel@vger.kernel.org, Minchan Kim <minchan@kernel.org>,
dri-devel@lists.freedesktop.org, xen-devel@lists.xenproject.org,
Andrew Morton <akpm@linux-foundation.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Nitin Gupta <ngupta@vflare.org>
Subject: Re: [Intel-gfx] [PATCH 3/6] drm/i915: use vmap in shmem_pin_map
Date: Tue, 22 Sep 2020 15:53:23 +0100 [thread overview]
Message-ID: <20200922145323.GG32101@casper.infradead.org> (raw)
In-Reply-To: <20200922143906.GB26664@lst.de>
On Tue, Sep 22, 2020 at 04:39:06PM +0200, Christoph Hellwig wrote:
> On Tue, Sep 22, 2020 at 12:21:44PM +0100, Matthew Wilcox wrote:
> > Actually, vfree() will work today; I cc'd you on a documentation update
> > to make it clear that this is permitted.
>
> vfree calls __free_pages, the i915 and a lot of other code calls
> put_page. They are mostly the same, but not quite and everytime I
> look into that mess I'm more confused than before.
>
> Can someone in the know write sensible documentation on when to use
> __free_page(s) vs put_page?
I started on that, and then I found a bug that's been lurking for 12
years, so that delayed the documentation somewhat. The short answer is
that __free_pages() lets you free non-compound high-order pages while
put_page() can only free order-0 and compound pages.
I would really like to overhaul our memory allocation APIs:
current new
__get_free_page(s) alloc_page(s)
free_page(s) free_page(s)
alloc_page(s) get_free_page(s)
__free_pages put_page_order
Then put_page() and put_page_order() are more obviously friends.
But I cannot imagine a world in which Linus says yes to that upheaval.
He's previous expressed dislike of the get_free_page() family of APIs,
and thinks all those callers should just use kmalloc(). Maybe we can
make that transition happen, now that kmalloc() aligns larger allocations.
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx
next prev parent reply other threads:[~2020-09-22 14:53 UTC|newest]
Thread overview: 85+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-18 16:37 remove alloc_vm_area Christoph Hellwig
2020-09-18 16:37 ` [Intel-gfx] " Christoph Hellwig
2020-09-18 16:37 ` [PATCH 1/6] zsmalloc: switch from alloc_vm_area to get_vm_area Christoph Hellwig
2020-09-18 16:37 ` [Intel-gfx] " Christoph Hellwig
2020-09-21 17:42 ` Minchan Kim
2020-09-21 17:42 ` [Intel-gfx] " Minchan Kim
2020-09-21 17:42 ` Minchan Kim
2020-09-21 18:17 ` Christoph Hellwig
2020-09-21 18:17 ` [Intel-gfx] " Christoph Hellwig
2020-09-21 18:42 ` Minchan Kim
2020-09-21 18:42 ` [Intel-gfx] " Minchan Kim
2020-09-21 18:42 ` Minchan Kim
2020-09-21 18:43 ` Christoph Hellwig
2020-09-21 18:43 ` [Intel-gfx] " Christoph Hellwig
2020-09-18 16:37 ` [PATCH 2/6] mm: add a vmap_pfn function Christoph Hellwig
2020-09-18 16:37 ` [Intel-gfx] " Christoph Hellwig
2020-09-18 16:37 ` [PATCH 3/6] drm/i915: use vmap in shmem_pin_map Christoph Hellwig
2020-09-18 16:37 ` [Intel-gfx] " Christoph Hellwig
2020-09-21 19:11 ` Matthew Wilcox
2020-09-21 19:11 ` [Intel-gfx] " Matthew Wilcox
2020-09-21 19:11 ` Matthew Wilcox
2020-09-22 6:22 ` Christoph Hellwig
2020-09-22 6:22 ` [Intel-gfx] " Christoph Hellwig
2020-09-22 8:23 ` Tvrtko Ursulin
2020-09-22 8:23 ` Tvrtko Ursulin
2020-09-22 8:23 ` Tvrtko Ursulin
2020-09-22 14:31 ` Christoph Hellwig
2020-09-22 14:31 ` Christoph Hellwig
2020-09-22 16:13 ` Tvrtko Ursulin
2020-09-22 16:13 ` Tvrtko Ursulin
2020-09-22 16:13 ` Tvrtko Ursulin
2020-09-22 16:33 ` Christoph Hellwig
2020-09-22 16:33 ` Christoph Hellwig
2020-09-22 17:04 ` Tvrtko Ursulin
2020-09-22 17:04 ` Tvrtko Ursulin
2020-09-22 17:04 ` Tvrtko Ursulin
2020-09-23 6:11 ` Christoph Hellwig
2020-09-23 6:11 ` Christoph Hellwig
2020-09-22 11:21 ` Matthew Wilcox
2020-09-22 11:21 ` [Intel-gfx] " Matthew Wilcox
2020-09-22 11:21 ` Matthew Wilcox
2020-09-22 14:39 ` Christoph Hellwig
2020-09-22 14:39 ` [Intel-gfx] " Christoph Hellwig
2020-09-22 14:53 ` Matthew Wilcox [this message]
2020-09-22 14:53 ` Matthew Wilcox
2020-09-22 14:53 ` Matthew Wilcox
2020-09-18 16:37 ` [PATCH 4/6] drm/i915: use vmap in i915_gem_object_map Christoph Hellwig
2020-09-18 16:37 ` [Intel-gfx] " Christoph Hellwig
2020-09-23 9:52 ` Tvrtko Ursulin
2020-09-23 9:52 ` Tvrtko Ursulin
2020-09-23 9:52 ` Tvrtko Ursulin
2020-09-23 13:41 ` Christoph Hellwig
2020-09-23 13:41 ` Christoph Hellwig
2020-09-23 13:58 ` Tvrtko Ursulin
2020-09-23 13:58 ` Tvrtko Ursulin
2020-09-23 13:58 ` Tvrtko Ursulin
2020-09-23 14:44 ` Christoph Hellwig
2020-09-23 14:44 ` Christoph Hellwig
2020-09-24 12:22 ` Tvrtko Ursulin
2020-09-24 12:22 ` Tvrtko Ursulin
2020-09-24 12:22 ` Tvrtko Ursulin
2020-09-24 13:23 ` Christoph Hellwig
2020-09-24 13:23 ` Christoph Hellwig
2020-09-18 16:37 ` [PATCH 5/6] xen/xenbus: use apply_to_page_range directly in xenbus_map_ring_pv Christoph Hellwig
2020-09-18 16:37 ` [Intel-gfx] " Christoph Hellwig
2020-09-18 16:37 ` [PATCH 6/6] x86/xen: open code alloc_vm_area in arch_gnttab_valloc Christoph Hellwig
2020-09-18 16:37 ` [Intel-gfx] " Christoph Hellwig
2020-09-21 20:44 ` boris.ostrovsky
2020-09-21 20:44 ` [Intel-gfx] " boris.ostrovsky
2020-09-21 20:44 ` boris.ostrovsky
2020-09-22 14:58 ` Christoph Hellwig
2020-09-22 14:58 ` [Intel-gfx] " Christoph Hellwig
2020-09-22 15:24 ` boris.ostrovsky
2020-09-22 15:24 ` [Intel-gfx] " boris.ostrovsky
2020-09-22 15:24 ` boris.ostrovsky
2020-09-22 15:27 ` Christoph Hellwig
2020-09-22 15:27 ` [Intel-gfx] " Christoph Hellwig
2020-09-22 15:34 ` boris.ostrovsky
2020-09-22 15:34 ` [Intel-gfx] " boris.ostrovsky
2020-09-22 15:34 ` boris.ostrovsky
2020-09-18 17:03 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for series starting with [1/6] zsmalloc: switch from alloc_vm_area to get_vm_area Patchwork
2020-09-21 17:50 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for series starting with [1/6] zsmalloc: switch from alloc_vm_area to get_vm_area (rev2) Patchwork
2020-09-21 18:47 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for series starting with [1/6] zsmalloc: switch from alloc_vm_area to get_vm_area (rev3) Patchwork
2020-09-22 14:44 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for series starting with [1/6] zsmalloc: switch from alloc_vm_area to get_vm_area (rev4) Patchwork
2020-09-22 15:01 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for series starting with [1/6] zsmalloc: switch from alloc_vm_area to get_vm_area (rev5) Patchwork
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200922145323.GG32101@casper.infradead.org \
--to=willy@infradead.org \
--cc=akpm@linux-foundation.org \
--cc=boris.ostrovsky@oracle.com \
--cc=dri-devel@lists.freedesktop.org \
--cc=hch@lst.de \
--cc=intel-gfx@lists.freedesktop.org \
--cc=jani.nikula@linux.intel.com \
--cc=jgross@suse.com \
--cc=joonas.lahtinen@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=minchan@kernel.org \
--cc=ngupta@vflare.org \
--cc=peterz@infradead.org \
--cc=rodrigo.vivi@intel.com \
--cc=sstabellini@kernel.org \
--cc=x86@kernel.org \
--cc=xen-devel@lists.xenproject.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.