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Mon, 10 Feb 2020 10:12:17 +0000 (UTC) Received: from [10.36.117.242] (ovpn-117-242.ams2.redhat.com [10.36.117.242]) by smtp.corp.redhat.com (Postfix) with ESMTP id AAE5189F2A; Mon, 10 Feb 2020 10:12:12 +0000 (UTC) Subject: Re: [PATCH v1 13/13] exec: Ram blocks with resizable anonymous allocations under POSIX To: qemu-devel@nongnu.org References: <20200203183125.164879-1-david@redhat.com> <20200203183125.164879-14-david@redhat.com> From: David Hildenbrand Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= mQINBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABtCREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT6JAlgEEwEIAEICGwMFCQlmAYAGCwkIBwMCBhUI AgkKCwQWAgMBAh4BAheAFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl3pImkCGQEACgkQTd4Q 9wD/g1o+VA//SFvIHUAvul05u6wKv/pIR6aICPdpF9EIgEU448g+7FfDgQwcEny1pbEzAmiw zAXIQ9H0NZh96lcq+yDLtONnXk/bEYWHHUA014A1wqcYNRY8RvY1+eVHb0uu0KYQoXkzvu+s Dncuguk470XPnscL27hs8PgOP6QjG4jt75K2LfZ0eAqTOUCZTJxA8A7E9+XTYuU0hs7QVrWJ jQdFxQbRMrYz7uP8KmTK9/Cnvqehgl4EzyRaZppshruKMeyheBgvgJd5On1wWq4ZUV5PFM4x II3QbD3EJfWbaJMR55jI9dMFa+vK7MFz3rhWOkEx/QR959lfdRSTXdxs8V3zDvChcmRVGN8U Vo93d1YNtWnA9w6oCW1dnDZ4kgQZZSBIjp6iHcA08apzh7DPi08jL7M9UQByeYGr8KuR4i6e RZI6xhlZerUScVzn35ONwOC91VdYiQgjemiVLq1WDDZ3B7DIzUZ4RQTOaIWdtXBWb8zWakt/ ztGhsx0e39Gvt3391O1PgcA7ilhvqrBPemJrlb9xSPPRbaNAW39P8ws/UJnzSJqnHMVxbRZC Am4add/SM+OCP0w3xYss1jy9T+XdZa0lhUvJfLy7tNcjVG/sxkBXOaSC24MFPuwnoC9WvCVQ ZBxouph3kqc4Dt5X1EeXVLeba+466P1fe1rC8MbcwDkoUo65Ag0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAGJAiUEGAECAA8FAlXLn5ECGwwFCQlmAYAACgkQTd4Q 9wD/g1qA6w/+M+ggFv+JdVsz5+ZIc6MSyGUozASX+bmIuPeIecc9UsFRatc91LuJCKMkD9Uv GOcWSeFpLrSGRQ1Z7EMzFVU//qVs6uzhsNk0RYMyS0B6oloW3FpyQ+zOVylFWQCzoyyf227y GW8HnXunJSC+4PtlL2AY4yZjAVAPLK2l6mhgClVXTQ/S7cBoTQKP+jvVJOoYkpnFxWE9pn4t H5QIFk7Ip8TKr5k3fXVWk4lnUi9MTF/5L/mWqdyIO1s7cjharQCstfWCzWrVeVctpVoDfJWp 4LwTuQ5yEM2KcPeElLg5fR7WB2zH97oI6/Ko2DlovmfQqXh9xWozQt0iGy5tWzh6I0JrlcxJ ileZWLccC4XKD1037Hy2FLAjzfoWgwBLA6ULu0exOOdIa58H4PsXtkFPrUF980EEibUp0zFz GotRVekFAceUaRvAj7dh76cToeZkfsjAvBVb4COXuhgX6N4pofgNkW2AtgYu1nUsPAo+NftU CxrhjHtLn4QEBpkbErnXQyMjHpIatlYGutVMS91XTQXYydCh5crMPs7hYVsvnmGHIaB9ZMfB njnuI31KBiLUks+paRkHQlFcgS2N3gkRBzH7xSZ+t7Re3jvXdXEzKBbQ+dC3lpJB0wPnyMcX FOTT3aZT7IgePkt5iC/BKBk3hqKteTnJFeVIT7EC+a6YUFg= Organization: Red Hat GmbH Message-ID: <4030a9f7-9a21-edd9-0344-4860fb92eabe@redhat.com> Date: Mon, 10 Feb 2020 11:12:11 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200203183125.164879-14-david@redhat.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-MC-Unique: 7-AonS8RMGm83oLRRyE6Zg-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Eduardo Habkost , "Michael S . Tsirkin" , Stefan Weil , "Dr . David Alan Gilbert" , Paolo Bonzini , Richard Henderson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 03.02.20 19:31, David Hildenbrand wrote: > We can now make use of resizable anonymous allocations to implement > actually resizable ram blocks. Resizable anonymous allocations are > not implemented under WIN32 yet and are not available when using > alternative allocators. Fall back to the existing handling. > > We also have to fallback to the existing handling in case any ram block > notifier does not support resizing (esp., AMD SEV, HAX) yet. Remember > in RAM_RESIZEABLE_ALLOC if we are using resizable anonymous allocations. > > As the mmap()-hackery will invalidate some madvise settings, we have to > re-apply them after resizing. After resizing, notify the ram block > notifiers. > > The benefit of actually resizable ram blocks is that e.g., under Linux, > only the actual size will be reserved (even if > "/proc/sys/vm/overcommit_memory" is set to "never"). Additional memory will > be reserved when trying to resize, which allows to have ram blocks that > start small but can theoretically grow very large. > > Cc: Richard Henderson > Cc: Paolo Bonzini > Cc: "Dr. David Alan Gilbert" > Cc: Eduardo Habkost > Cc: Marcel Apfelbaum > Cc: Stefan Weil > Signed-off-by: David Hildenbrand > --- > exec.c | 68 +++++++++++++++++++++++++++++++++++---- > hw/core/numa.c | 10 ++++-- > include/exec/cpu-common.h | 2 ++ > include/exec/memory.h | 8 +++++ > 4 files changed, 79 insertions(+), 9 deletions(-) > > diff --git a/exec.c b/exec.c > index fc65c4f7ca..a59d1efde3 100644 > --- a/exec.c > +++ b/exec.c > @@ -2053,6 +2053,16 @@ void qemu_ram_unset_migratable(RAMBlock *rb) > rb->flags &= ~RAM_MIGRATABLE; > } > > +bool qemu_ram_is_resizable(RAMBlock *rb) > +{ > + return rb->flags & RAM_RESIZEABLE; > +} > + > +bool qemu_ram_is_resizable_alloc(RAMBlock *rb) > +{ > + return rb->flags & RAM_RESIZEABLE_ALLOC; > +} > + > /* Called with iothread lock held. */ > void qemu_ram_set_idstr(RAMBlock *new_block, const char *name, DeviceState *dev) > { > @@ -2139,6 +2149,8 @@ static void qemu_ram_apply_settings(void *host, size_t length) > */ > int qemu_ram_resize(RAMBlock *block, ram_addr_t newsize, Error **errp) > { > + const uint64_t oldsize = block->used_length; > + > assert(block); > > newsize = HOST_PAGE_ALIGN(newsize); > @@ -2147,7 +2159,7 @@ int qemu_ram_resize(RAMBlock *block, ram_addr_t newsize, Error **errp) > return 0; > } > > - if (!(block->flags & RAM_RESIZEABLE)) { > + if (!qemu_ram_is_resizable(block)) { > error_setg_errno(errp, EINVAL, > "Length mismatch: %s: 0x" RAM_ADDR_FMT > " in != 0x" RAM_ADDR_FMT, block->idstr, > @@ -2163,10 +2175,26 @@ int qemu_ram_resize(RAMBlock *block, ram_addr_t newsize, Error **errp) > return -EINVAL; > } > > + if (qemu_ram_is_resizable_alloc(block)) { > + g_assert(ram_block_notifiers_support_resize()); > + if (qemu_anon_ram_resize(block->host, block->used_length, > + newsize, block->flags & RAM_SHARED) == NULL) { > + error_setg_errno(errp, -ENOMEM, > + "Could not allocate enough memory."); > + return -ENOMEM; > + } > + } > + I'll most probably rework to have separate paths when growing/shrinking, with a different sequence of steps. (e.g., perform actual shrinking as last step, so all mappings remain valid, and ignore errors (which are unlikely either way)). -- Thanks, David / dhildenb