From: "Michael S. Tsirkin" <mst@redhat.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Wei Wang <wei.w.wang@intel.com>,
virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
linux-mm@kvack.org, mhocko@kernel.org, akpm@linux-foundation.org,
torvalds@linux-foundation.org, pbonzini@redhat.com,
liliang.opensource@gmail.com, yang.zhang.wz@gmail.com,
quan.xu0@gmail.com, nilal@redhat.com, riel@redhat.com,
peterx@redhat.com
Subject: Re: [PATCH v33 1/4] mm: add a function to get free page blocks
Date: Mon, 18 Jun 2018 05:16:02 +0300 [thread overview]
Message-ID: <20180618051145-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20180616045005.GA14936@bombadil.infradead.org>
On Fri, Jun 15, 2018 at 09:50:05PM -0700, Matthew Wilcox wrote:
> I wonder if (to address Michael's concern), you shouldn't instead use
> the first free chunk of pages to return the addresses of all the pages.
> ie something like this:
>
> __le64 *ret = NULL;
> unsigned int max = (PAGE_SIZE << order) / sizeof(__le64);
>
> for_each_populated_zone(zone) {
> spin_lock_irq(&zone->lock);
> for (mt = 0; mt < MIGRATE_TYPES; mt++) {
> list = &zone->free_area[order].free_list[mt];
> list_for_each_entry_safe(page, list, lru, ...) {
> if (index == size)
> break;
> addr = page_to_pfn(page) << PAGE_SHIFT;
> if (!ret) {
> list_del(...);
> ret = addr;
> }
> ret[index++] = cpu_to_le64(addr);
> }
> }
> spin_unlock_irq(&zone->lock);
> }
>
> return ret;
> }
>
> You'll need to return the page to the freelist afterwards, but free_pages()
> should take care of that.
Yes Wei already came up with the idea to stick this data into a
MAX_ORDER allocation. Are you sure just taking an entry off
the list like that has no bad side effects?
I have a vague memory someone complained that everyone
most go through get free pages/kmalloc, but I can't
find that anymore.
--
MST
next prev parent reply other threads:[~2018-06-18 2:16 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-15 4:43 [PATCH v33 0/4] Virtio-balloon: support free page reporting Wei Wang
2018-06-15 4:43 ` [PATCH v33 1/4] mm: add a function to get free page blocks Wei Wang
2018-06-15 23:08 ` Linus Torvalds
2018-06-16 1:19 ` Wang, Wei W
2018-06-26 1:55 ` Michael S. Tsirkin
2018-06-27 16:05 ` Linus Torvalds
2018-06-27 19:07 ` Michael S. Tsirkin
2018-06-28 8:39 ` Wei Wang
2018-06-16 4:50 ` Matthew Wilcox
2018-06-17 0:07 ` Wang, Wei W
2018-06-18 2:16 ` Michael S. Tsirkin [this message]
2018-06-15 4:43 ` [PATCH v33 2/4] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT Wei Wang
2018-06-15 11:42 ` Michael S. Tsirkin
2018-06-15 14:11 ` Wang, Wei W
2018-06-15 14:29 ` Michael S. Tsirkin
2018-06-16 1:09 ` Wang, Wei W
2018-06-18 2:28 ` Michael S. Tsirkin
2018-06-19 1:06 ` [virtio-dev] " Wang, Wei W
2018-06-19 3:05 ` Michael S. Tsirkin
2018-06-19 12:13 ` Wei Wang
2018-06-19 14:43 ` Michael S. Tsirkin
2018-06-20 9:11 ` Wang, Wei W
2018-06-20 14:14 ` Michael S. Tsirkin
2018-06-15 4:43 ` [PATCH v33 3/4] mm/page_poison: expose page_poisoning_enabled to kernel modules Wei Wang
2018-06-15 4:43 ` [PATCH v33 4/4] virtio-balloon: VIRTIO_BALLOON_F_PAGE_POISON Wei Wang
2018-06-15 11:29 ` [PATCH v33 0/4] Virtio-balloon: support free page reporting Michael S. Tsirkin
2018-06-15 14:28 ` Wang, Wei W
2018-06-15 14:38 ` Michael S. Tsirkin
2018-06-15 19:21 ` Luiz Capitulino
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