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bh=yOIHVYyv54egdlVoMdUVLVFk4lzZ/xlT1WvDt+htyXc=; b=G9W9cJcSUS7ydxnAbPhQI5P0YEFETCHCGhetaGqZxc4dBT40Sym3T1pklZnj67Q3KE175/ D23jYflk4Yf2Ij8wvtc9eHD6lcKJ8LPU3lw/AoL+ZZJ+xEoJUaSdweXkVdnZd3IDE4cZi3 eIX+Rm6wOWl9S2knNdkSAhkM63irXYU= X-MC-Unique: ZTD3sIyWPJCtcTfhIz3bmg-1 From: peterx@redhat.com To: Peter Maydell , qemu-devel@nongnu.org Cc: Fabiano Rosas , peterx@redhat.com Subject: [PULL 04/14] migration: Drop unnecessary check in ram's pending_exact() Date: Mon, 29 Jan 2024 11:03:55 +0800 Message-ID: <20240129030405.177100-5-peterx@redhat.com> In-Reply-To: <20240129030405.177100-1-peterx@redhat.com> References: <20240129030405.177100-1-peterx@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.3 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=170.10.129.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -45 X-Spam_score: -4.6 X-Spam_bar: ---- X-Spam_report: (-4.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-2.485, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1706497592700100001 Content-Type: text/plain; charset="utf-8" From: Peter Xu When the migration frameworks fetches the exact pending sizes, it means this check: remaining_size < s->threshold_size Must have been done already, actually at migration_iteration_run(): if (must_precopy <=3D s->threshold_size) { qemu_savevm_state_pending_exact(&must_precopy, &can_postcopy); That should be after one round of ram_state_pending_estimate(). It makes the 2nd check meaningless and can be dropped. To say it in another way, when reaching ->state_pending_exact(), we unconditionally sync dirty bits for precopy. Then we can drop migrate_get_current() there too. Reviewed-by: Fabiano Rosas Link: https://lore.kernel.org/r/20240117075848.139045-3-peterx@redhat.com Signed-off-by: Peter Xu --- migration/ram.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/migration/ram.c b/migration/ram.c index c0cdcccb75..d5b7cd5ac2 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -3213,21 +3213,20 @@ static void ram_state_pending_estimate(void *opaque= , uint64_t *must_precopy, static void ram_state_pending_exact(void *opaque, uint64_t *must_precopy, uint64_t *can_postcopy) { - MigrationState *s =3D migrate_get_current(); RAMState **temp =3D opaque; RAMState *rs =3D *temp; + uint64_t remaining_size; =20 - uint64_t remaining_size =3D rs->migration_dirty_pages * TARGET_PAGE_SI= ZE; - - if (!migration_in_postcopy() && remaining_size < s->threshold_size) { + if (!migration_in_postcopy()) { bql_lock(); WITH_RCU_READ_LOCK_GUARD() { migration_bitmap_sync_precopy(rs, false); } bql_unlock(); - remaining_size =3D rs->migration_dirty_pages * TARGET_PAGE_SIZE; } =20 + remaining_size =3D rs->migration_dirty_pages * TARGET_PAGE_SIZE; + if (migrate_postcopy_ram()) { /* We can do postcopy, and all the data is postcopiable */ *can_postcopy +=3D remaining_size; --=20 2.43.0