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David Alan Gilbert" , Andrey Gruzdev , Peter Xu , =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= , Alexey Romko , "open list:All patches CC here" Subject: [PATCH v3 3/3] migration/ram: Optimize ram_save_host_page() Date: Fri, 5 Mar 2021 15:50:35 +0800 Message-ID: <20210305075035.1852-4-jiangkunkun@huawei.com> X-Mailer: git-send-email 2.26.2.windows.1 In-Reply-To: <20210305075035.1852-1-jiangkunkun@huawei.com> References: <20210305075035.1852-1-jiangkunkun@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.174.185.210] X-CFilter-Loop: Reflected 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=45.249.212.35; envelope-from=jiangkunkun@huawei.com; helo=szxga07-in.huawei.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, 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: Zenghui Yu , wanghaibin.wang@huawei.com, Keqian Zhu Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" Starting from pss->page, ram_save_host_page() will check every page and send the dirty pages up to the end of the current host page or the boundary of used_length of the block. If the host page size is a huge page, the step "check" will take a lot of time. This will improve performance to use migration_bitmap_find_dirty(). Signed-off-by: Keqian Zhu Signed-off-by: Kunkun Jiang --- migration/ram.c | 39 +++++++++++++++++++-------------------- 1 file changed, 19 insertions(+), 20 deletions(-) diff --git a/migration/ram.c b/migration/ram.c index 9fc5b2997c..28215aefe4 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -1991,6 +1991,8 @@ static int ram_save_host_page(RAMState *rs, PageSearc= hStatus *pss, int pages =3D 0; size_t pagesize_bits =3D qemu_ram_pagesize(pss->block) >> TARGET_PAGE_BITS; + unsigned long hostpage_boundary =3D + QEMU_ALIGN_UP(pss->page + 1, pagesize_bits); unsigned long start_page =3D pss->page; int res; =20 @@ -2003,30 +2005,27 @@ static int ram_save_host_page(RAMState *rs, PageSea= rchStatus *pss, int pages_this_iteration =3D 0; =20 /* Check if the page is dirty and send it if it is */ - if (!migration_bitmap_clear_dirty(rs, pss->block, pss->page)) { - pss->page++; - continue; - } - - pages_this_iteration =3D ram_save_target_page(rs, pss, last_stage); - if (pages_this_iteration < 0) { - return pages_this_iteration; - } + if (migration_bitmap_clear_dirty(rs, pss->block, pss->page)) { + pages_this_iteration =3D ram_save_target_page(rs, pss, last_st= age); + if (pages_this_iteration < 0) { + return pages_this_iteration; + } =20 - pages +=3D pages_this_iteration; - pss->page++; - /* - * Allow rate limiting to happen in the middle of huge pages if - * something is sent in the current iteration. - */ - if (pagesize_bits > 1 && pages_this_iteration > 0) { - migration_rate_limit(); + pages +=3D pages_this_iteration; + /* + * Allow rate limiting to happen in the middle of huge pages if + * something is sent in the current iteration. + */ + if (pagesize_bits > 1 && pages_this_iteration > 0) { + migration_rate_limit(); + } } - } while ((pss->page & (pagesize_bits - 1)) && + pss->page =3D migration_bitmap_find_dirty(rs, pss->block, pss->pag= e); + } while ((pss->page < hostpage_boundary) && offset_in_ramblock(pss->block, ((ram_addr_t)pss->page) << TARGET_PAGE_BIT= S)); - /* The offset we leave with is the last one we looked at */ - pss->page--; + /* The offset we leave with is the min boundary of host page and block= */ + pss->page =3D MIN(pss->page, hostpage_boundary) - 1; =20 res =3D ram_save_release_protection(rs, pss, start_page); return (res < 0 ? res : pages); --=20 2.23.0