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bh=kut2k8AQFD2uy14NKFAlyp3n85fRNitFkihyuY071Hg=; b=Q8d0frJBKy44NR9skj84YhhCLyq0zxDDVlIx6IqCDzNLZcDxfxETjCNjvcp8hP7lzGaKT0 MW1AnWHtFQDXvEcnSFqoIKx7bP1juVq31/fvKEXvBjwSHJpHgZJg0PEupT/km97Q183+vx ijHXtHJy9Vmb3rHbdd2fwgHH1tVWHQg= X-MC-Unique: QlD_ODQKNjiZCMrP0rPeeA-1 From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, david@redhat.com, zhukeqian1@huawei.com, jiangkunkun@huawei.com, armbru@redhat.com, peter.maydell@linaro.org, huangy81@chinatelecom.cn Subject: [PULL 10/17] migration/ram: Discard RAM when growing RAM blocks after ram_postcopy_incoming_init() Date: Thu, 13 May 2021 18:37:30 +0100 Message-Id: <20210513173737.279402-11-dgilbert@redhat.com> In-Reply-To: <20210513173737.279402-1-dgilbert@redhat.com> References: <20210513173737.279402-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.133.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.699, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action 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: peterx@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) Content-Type: text/plain; charset="utf-8" From: David Hildenbrand In case we grow our RAM after ram_postcopy_incoming_init() (e.g., when synchronizing the RAM block state with the migration source), the resized part would not get discarded. Let's perform that when being notified about a resize while postcopy has been advised, but is not listening yet. With precopy, the process is as following: 1. VM created - RAM blocks are created 2. Incomming migration started - Postcopy is advised - All pages in RAM blocks are discarded 3. Precopy starts - RAM blocks are resized to match the size on the migration source. - RAM pages from precopy stream are loaded - Uffd handler is registered, postcopy starts listening 4. Guest started, postcopy running - Pagefaults get resolved, pages get placed Reviewed-by: Peter Xu Signed-off-by: David Hildenbrand Message-Id: <20210429112708.12291-7-david@redhat.com> Signed-off-by: Dr. David Alan Gilbert --- migration/ram.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/migration/ram.c b/migration/ram.c index 77922c445e..e1d081d334 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -4099,6 +4099,7 @@ static SaveVMHandlers savevm_ram_handlers =3D { static void ram_mig_ram_block_resized(RAMBlockNotifier *n, void *host, size_t old_size, size_t new_size) { + PostcopyState ps =3D postcopy_state_get(); ram_addr_t offset; RAMBlock *rb =3D qemu_ram_block_from_host(host, false, &offset); Error *err =3D NULL; @@ -4119,6 +4120,35 @@ static void ram_mig_ram_block_resized(RAMBlockNotifi= er *n, void *host, error_free(err); migration_cancel(); } + + switch (ps) { + case POSTCOPY_INCOMING_ADVISE: + /* + * Update what ram_postcopy_incoming_init()->init_range() does at = the + * time postcopy was advised. Syncing RAM blocks with the source w= ill + * result in RAM resizes. + */ + if (old_size < new_size) { + if (ram_discard_range(rb->idstr, old_size, new_size - old_size= )) { + error_report("RAM block '%s' discard of resized RAM failed= ", + rb->idstr); + } + } + break; + case POSTCOPY_INCOMING_NONE: + case POSTCOPY_INCOMING_RUNNING: + case POSTCOPY_INCOMING_END: + /* + * Once our guest is running, postcopy does no longer care about + * resizes. When growing, the new memory was not available on the + * source, no handler needed. + */ + break; + default: + error_report("RAM block '%s' resized during postcopy state: %d", + rb->idstr, ps); + exit(-1); + } } =20 static RAMBlockNotifier ram_mig_ram_notifier =3D { --=20 2.31.1