From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-dev-return-5169-cohuck=redhat.com@lists.oasis-open.org Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 3B43A985C84 for ; Tue, 11 Dec 2018 08:58:01 +0000 (UTC) From: Wei Wang Date: Tue, 11 Dec 2018 16:24:50 +0800 Message-Id: <1544516693-5395-5-git-send-email-wei.w.wang@intel.com> In-Reply-To: <1544516693-5395-1-git-send-email-wei.w.wang@intel.com> References: <1544516693-5395-1-git-send-email-wei.w.wang@intel.com> Subject: [virtio-dev] [PATCH v11 4/7] migration: API to clear bits of guest free pages from the dirty bitmap To: qemu-devel@nongnu.org, virtio-dev@lists.oasis-open.org, mst@redhat.com, quintela@redhat.com, dgilbert@redhat.com, peterx@redhat.com Cc: pbonzini@redhat.com, liliang.opensource@gmail.com, nilal@redhat.com, riel@redhat.com, wei.w.wang@intel.com List-ID: This patch adds an API to clear bits corresponding to guest free pages from the dirty bitmap. Spilt the free page block if it crosses the QEMU RAMBlock boundary. Signed-off-by: Wei Wang CC: Dr. David Alan Gilbert CC: Juan Quintela CC: Michael S. Tsirkin CC: Peter Xu Reviewed-by: Peter Xu --- include/migration/misc.h | 2 ++ migration/ram.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 49 insertions(+) diff --git a/include/migration/misc.h b/include/migration/misc.h index 4ebf24c..113320e 100644 --- a/include/migration/misc.h +++ b/include/migration/misc.h @@ -14,11 +14,13 @@ #ifndef MIGRATION_MISC_H #define MIGRATION_MISC_H +#include "exec/cpu-common.h" #include "qemu/notify.h" /* migration/ram.c */ void ram_mig_init(void); +void qemu_guest_free_page_hint(void *addr, size_t len); /* migration/block.c */ diff --git a/migration/ram.c b/migration/ram.c index 01d267f..c13b44f 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -3131,6 +3131,53 @@ static void ram_state_resume_prepare(RAMState *rs, QEMUFile *out) } /* + * This function clears bits of the free pages reported by the caller from the + * migration dirty bitmap. @addr is the host address corresponding to the + * start of the continuous guest free pages, and @len is the total bytes of + * those pages. + */ +void qemu_guest_free_page_hint(void *addr, size_t len) +{ + RAMBlock *block; + ram_addr_t offset; + size_t used_len, start, npages; + MigrationState *s = migrate_get_current(); + + /* This function is currently expected to be used during live migration */ + if (!migration_is_setup_or_active(s->state)) { + return; + } + + for (; len > 0; len -= used_len, addr += used_len) { + block = qemu_ram_block_from_host(addr, false, &offset); + if (unlikely(!block || offset >= block->used_length)) { + /* + * The implementation might not support RAMBlock resize during + * live migration, but it could happen in theory with future + * updates. So we add a check here to capture that case. + */ + error_report_once("%s unexpected error", __func__); + return; + } + + if (len <= block->used_length - offset) { + used_len = len; + } else { + used_len = block->used_length - offset; + } + + start = offset >> TARGET_PAGE_BITS; + npages = used_len >> TARGET_PAGE_BITS; + + qemu_mutex_lock(&ram_state->bitmap_mutex); + ram_state->migration_dirty_pages -= + bitmap_count_one_with_offset(block->bmap, start, npages); + bitmap_clear(block->bmap, start, npages); + qemu_mutex_unlock(&ram_state->bitmap_mutex); + } +} + +/* * Each of ram_save_setup, ram_save_iterate and ram_save_complete has * long-running RCU critical section. When rcu-reclaims in the code * start to become numerous it will be necessary to reduce the -- 1.8.3.1 --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org