From: Michal Hocko <mhocko@kernel.org>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Wei Wang <wei.w.wang@intel.com>,
virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org,
qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org,
kvm@vger.kernel.org, linux-mm@kvack.org,
akpm@linux-foundation.org, mawilcox@microsoft.com,
david@redhat.com, cornelia.huck@de.ibm.com,
mgorman@techsingularity.net, aarcange@redhat.com,
amit.shah@redhat.com, pbonzini@redhat.com, willy@infradead.org,
liliang.opensource@gmail.com, yang.zhang.wz@gmail.com,
quan.xu@aliyun.com
Subject: Re: [PATCH v14 4/5] mm: support reporting free page blocks
Date: Mon, 21 Aug 2017 08:18:12 +0200 [thread overview]
Message-ID: <20170821061812.GB13724@dhcp22.suse.cz> (raw)
In-Reply-To: <20170818201946-mutt-send-email-mst@kernel.org>
On Fri 18-08-17 20:23:05, Michael S. Tsirkin wrote:
> On Thu, Aug 17, 2017 at 11:26:55AM +0800, Wei Wang wrote:
[...]
> > +void walk_free_mem_block(void *opaque1,
> > + unsigned int min_order,
> > + void (*visit)(void *opaque2,
>
> You can just avoid opaque2 completely I think, then opaque1 can
> be renamed opaque.
>
> > + unsigned long pfn,
> > + unsigned long nr_pages))
> > +{
> > + struct zone *zone;
> > + struct page *page;
> > + struct list_head *list;
> > + unsigned int order;
> > + enum migratetype mt;
> > + unsigned long pfn, flags;
> > +
> > + for_each_populated_zone(zone) {
> > + for (order = MAX_ORDER - 1;
> > + order < MAX_ORDER && order >= min_order; order--) {
> > + for (mt = 0; mt < MIGRATE_TYPES; mt++) {
> > + spin_lock_irqsave(&zone->lock, flags);
> > + list = &zone->free_area[order].free_list[mt];
> > + list_for_each_entry(page, list, lru) {
> > + pfn = page_to_pfn(page);
> > + visit(opaque1, pfn, 1 << order);
>
> My only concern here is inability of callback to
> 1. break out of list
> 2. remove page from the list
As I've said before this has to be a read only API. You cannot simply
fiddle with the page allocator internals under its feet.
> So I would make the callback bool, and I would use
> list_for_each_entry_safe.
If a bool would tell to break out of the loop then I agree. This sounds
useful.
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2017-08-21 6:18 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-17 3:26 [PATCH v14 0/5] Virtio-balloon Enhancement Wei Wang
2017-08-17 3:26 ` [PATCH v14 1/5] lib/xbitmap: Introduce xbitmap Wei Wang
2017-08-19 20:30 ` kbuild test robot
2017-08-17 3:26 ` [PATCH v14 2/5] lib/xbitmap: add xb_find_next_bit() and xb_zero() Wei Wang
2017-08-17 3:26 ` [PATCH v14 3/5] virtio-balloon: VIRTIO_BALLOON_F_SG Wei Wang
2017-08-18 2:22 ` Michael S. Tsirkin
2017-08-18 7:39 ` Wei Wang
2017-08-21 20:22 ` Michael S. Tsirkin
2017-08-19 21:37 ` kbuild test robot
2017-08-17 3:26 ` [PATCH v14 4/5] mm: support reporting free page blocks Wei Wang
2017-08-18 13:46 ` Michal Hocko
2017-08-21 6:12 ` Wei Wang
2017-08-21 6:14 ` Michal Hocko
2017-08-18 17:23 ` Michael S. Tsirkin
2017-08-21 6:18 ` Michal Hocko [this message]
2017-08-17 3:26 ` [PATCH v14 5/5] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_VQ Wei Wang
2017-08-18 2:13 ` Michael S. Tsirkin
2017-08-18 8:41 ` Wei Wang
2017-08-18 18:26 ` Michael S. Tsirkin
2017-08-21 5:21 ` Wei Wang
2017-08-18 2:28 ` Michael S. Tsirkin
2017-08-18 8:36 ` Wei Wang
2017-08-18 18:10 ` Michael S. Tsirkin
2017-08-21 5:28 ` [virtio-dev] " Wei Wang
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