From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47262) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ejOIt-000055-G8 for qemu-devel@nongnu.org; Wed, 07 Feb 2018 06:54:20 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ejOIq-0003T0-Ci for qemu-devel@nongnu.org; Wed, 07 Feb 2018 06:54:19 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:59126 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ejOIp-0003Sq-Uc for qemu-devel@nongnu.org; Wed, 07 Feb 2018 06:54:16 -0500 Date: Wed, 7 Feb 2018 11:54:06 +0000 From: "Dr. David Alan Gilbert" Message-ID: <20180207115406.GD2665@work-vm> References: <20180207073331.14158-1-haozhong.zhang@intel.com> <20180207073331.14158-8-haozhong.zhang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180207073331.14158-8-haozhong.zhang@intel.com> Subject: Re: [Qemu-devel] [PATCH v2 7/8] migration/ram: ensure write persistence on loading compressed pages to PMEM List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Haozhong Zhang Cc: qemu-devel@nongnu.org, Eduardo Habkost , Igor Mammedov , Paolo Bonzini , mst@redhat.com, Xiao Guangrong , Juan Quintela , Stefan Hajnoczi , Dan Williams * Haozhong Zhang (haozhong.zhang@intel.com) wrote: > When loading a compressed page to persistent memory, flush CPU cache > after the data is decompressed. Combined with a call to pmem_drain() > at the end of memory loading, we can guarantee those compressed pages > are persistently loaded to PMEM. Can you explain why this can use the flush and doesn't need the special memset? Dave > Signed-off-by: Haozhong Zhang > --- > include/qemu/pmem.h | 4 ++++ > migration/ram.c | 16 +++++++++++----- > 2 files changed, 15 insertions(+), 5 deletions(-) > > diff --git a/include/qemu/pmem.h b/include/qemu/pmem.h > index 77ee1fc4eb..20e3f6e71d 100644 > --- a/include/qemu/pmem.h > +++ b/include/qemu/pmem.h > @@ -37,6 +37,10 @@ static inline void *pmem_memset_nodrain(void *pmemdest, int c, size_t len) > return memset(pmemdest, c, len); > } > > +static inline void pmem_flush(const void *addr, size_t len) > +{ > +} > + > static inline void pmem_drain(void) > { > } > diff --git a/migration/ram.c b/migration/ram.c > index 5a79bbff64..924d2b9537 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -274,6 +274,7 @@ struct DecompressParam { > void *des; > uint8_t *compbuf; > int len; > + bool is_pmem; > }; > typedef struct DecompressParam DecompressParam; > > @@ -2502,7 +2503,7 @@ static void *do_data_decompress(void *opaque) > DecompressParam *param = opaque; > unsigned long pagesize; > uint8_t *des; > - int len; > + int len, rc; > > qemu_mutex_lock(¶m->mutex); > while (!param->quit) { > @@ -2518,8 +2519,11 @@ static void *do_data_decompress(void *opaque) > * not a problem because the dirty page will be retransferred > * and uncompress() won't break the data in other pages. > */ > - uncompress((Bytef *)des, &pagesize, > - (const Bytef *)param->compbuf, len); > + rc = uncompress((Bytef *)des, &pagesize, > + (const Bytef *)param->compbuf, len); > + if (rc == Z_OK && param->is_pmem) { > + pmem_flush(des, len); > + } > > qemu_mutex_lock(&decomp_done_lock); > param->done = true; > @@ -2605,7 +2609,8 @@ static void compress_threads_load_cleanup(void) > } > > static void decompress_data_with_multi_threads(QEMUFile *f, > - void *host, int len) > + void *host, int len, > + bool is_pmem) > { > int idx, thread_count; > > @@ -2619,6 +2624,7 @@ static void decompress_data_with_multi_threads(QEMUFile *f, > qemu_get_buffer(f, decomp_param[idx].compbuf, len); > decomp_param[idx].des = host; > decomp_param[idx].len = len; > + decomp_param[idx].is_pmem = is_pmem; > qemu_cond_signal(&decomp_param[idx].cond); > qemu_mutex_unlock(&decomp_param[idx].mutex); > break; > @@ -2964,7 +2970,7 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) > ret = -EINVAL; > break; > } > - decompress_data_with_multi_threads(f, host, len); > + decompress_data_with_multi_threads(f, host, len, is_pmem); > break; > > case RAM_SAVE_FLAG_XBZRLE: > -- > 2.14.1 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK