From: "Zhang, Chen" <chen.zhang@intel.com>
To: "Dr. David Alan Gilbert" <dgilbert@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>,
"quintela@redhat.com" <quintela@redhat.com>
Cc: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Subject: Re: [PATCH] colo: fix return without releasing RCU
Date: Sun, 15 Dec 2019 01:47:35 +0800 [thread overview]
Message-ID: <344c0a76-6a7d-ae34-fa09-e49284789dbc@intel.com> (raw)
In-Reply-To: <20191213150341.GG3713@work-vm>
On 12/13/2019 11:03 PM, Dr. David Alan Gilbert wrote:
> * Paolo Bonzini (pbonzini@redhat.com) wrote:
>> Use WITH_RCU_READ_LOCK_GUARD to avoid exiting colo_init_ram_cache
>> without releasing RCU.
>>
>> Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Zhang Chen <chen.zhang@intel.com>
>
>> ---
>> migration/ram.c | 33 +++++++++++++++++----------------
>> 1 file changed, 17 insertions(+), 16 deletions(-)
>>
>> diff --git a/migration/ram.c b/migration/ram.c
>> index 7dd7f81..8d7c015 100644
>> --- a/migration/ram.c
>> +++ b/migration/ram.c
>> @@ -3891,26 +3891,27 @@ int colo_init_ram_cache(void)
>> {
>> RAMBlock *block;
>>
>> - rcu_read_lock();
>> - RAMBLOCK_FOREACH_NOT_IGNORED(block) {
>> - block->colo_cache = qemu_anon_ram_alloc(block->used_length,
>> - NULL,
>> - false);
>> - if (!block->colo_cache) {
>> - error_report("%s: Can't alloc memory for COLO cache of block %s,"
>> - "size 0x" RAM_ADDR_FMT, __func__, block->idstr,
>> - block->used_length);
>> - RAMBLOCK_FOREACH_NOT_IGNORED(block) {
>> - if (block->colo_cache) {
>> - qemu_anon_ram_free(block->colo_cache, block->used_length);
>> - block->colo_cache = NULL;
>> + WITH_RCU_READ_LOCK_GUARD() {
>> + RAMBLOCK_FOREACH_NOT_IGNORED(block) {
>> + block->colo_cache = qemu_anon_ram_alloc(block->used_length,
>> + NULL,
>> + false);
>> + if (!block->colo_cache) {
>> + error_report("%s: Can't alloc memory for COLO cache of block %s,"
>> + "size 0x" RAM_ADDR_FMT, __func__, block->idstr,
>> + block->used_length);
>> + RAMBLOCK_FOREACH_NOT_IGNORED(block) {
>> + if (block->colo_cache) {
>> + qemu_anon_ram_free(block->colo_cache, block->used_length);
>> + block->colo_cache = NULL;
>> + }
>> }
>> + return -errno;
>> }
>> - return -errno;
>> + memcpy(block->colo_cache, block->host, block->used_length);
>> }
>> - memcpy(block->colo_cache, block->host, block->used_length);
>> }
>> - rcu_read_unlock();
>> +
>> /*
>> * Record the dirty pages that sent by PVM, we use this dirty bitmap together
>> * with to decide which page in cache should be flushed into SVM's RAM. Here
>> --
>> 1.8.3.1
>>
> --
> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
>
prev parent reply other threads:[~2019-12-14 21:11 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-13 14:08 [PATCH] colo: fix return without releasing RCU Paolo Bonzini
2019-12-13 15:03 ` Dr. David Alan Gilbert
2019-12-14 17:47 ` Zhang, Chen [this message]
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