From mboxrd@z Thu Jan 1 00:00:00 1970 From: Umesh Deshpande Subject: Re: [RFC PATCH v4 2/5] ramlist mutex Date: Fri, 19 Aug 2011 02:20:33 -0400 Message-ID: <4E4E00B1.9050009@redhat.com> References: <8f99d56f3a48b6255cf70425bc435d8f231f5352.1313552764.git.udeshpan@redhat.com> <4E4B5FA8.4020006@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, qemu-devel@nongnu.org, quintela@redhat.com, mtosatti@redhat.com To: Paolo Bonzini Return-path: Received: from mx1.redhat.com ([209.132.183.28]:2388 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751042Ab1HSGUi (ORCPT ); Fri, 19 Aug 2011 02:20:38 -0400 In-Reply-To: <4E4B5FA8.4020006@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 08/17/2011 02:28 AM, Paolo Bonzini wrote: > On 08/16/2011 08:56 PM, Umesh Deshpande wrote: >> @@ -3001,8 +3016,10 @@ void qemu_ram_free_from_ptr(ram_addr_t addr) >> >> QLIST_FOREACH(block,&ram_list.blocks, next) { >> if (addr == block->offset) { >> + qemu_mutex_lock_ramlist(); >> QLIST_REMOVE(block, next); >> QLIST_REMOVE(block, next_mru); >> + qemu_mutex_unlock_ramlist(); >> qemu_free(block); >> return; >> } >> @@ -3015,8 +3032,10 @@ void qemu_ram_free(ram_addr_t addr) >> >> QLIST_FOREACH(block,&ram_list.blocks, next) { >> if (addr == block->offset) { >> + qemu_mutex_lock_ramlist(); >> QLIST_REMOVE(block, next); >> QLIST_REMOVE(block, next_mru); >> + qemu_mutex_unlock_ramlist(); >> if (block->flags& RAM_PREALLOC_MASK) { >> ; >> } else if (mem_path) { > > You must protect the whole QLIST_FOREACH. Otherwise looks good. Or, is it okay to convert all the ramblock list traversals in exec.c (under iothread) to mru traversals, and probably it makes sense as the original list was also maintained in the mru order, whereas the sequence of blocks doesn't matter for the migration code. This way we don't have to acquire the mutex for block list traversals. - Umesh