From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59801) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W8vp6-0003Ov-76 for qemu-devel@nongnu.org; Thu, 30 Jan 2014 12:54:50 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W8voz-0002LX-U5 for qemu-devel@nongnu.org; Thu, 30 Jan 2014 12:54:44 -0500 Received: from mx1.redhat.com ([209.132.183.28]:18875) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W8voz-0002LP-LX for qemu-devel@nongnu.org; Thu, 30 Jan 2014 12:54:37 -0500 Message-ID: <52EA91FB.6030302@redhat.com> Date: Thu, 30 Jan 2014 19:55:07 +0200 From: Orit Wasserman MIME-Version: 1.0 References: <1391066055-17024-1-git-send-email-owasserm@redhat.com> <1391066055-17024-7-git-send-email-owasserm@redhat.com> <20140130160831.GC2655@work-vm> In-Reply-To: <20140130160831.GC2655@work-vm> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 6/6] Don't abort on memory allocation error List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert" Cc: peter.maydell@linaro.org, qemu-devel@nongnu.org, anthony@codemonkey.ws, quintela@redhat.com On 01/30/2014 06:08 PM, Dr. David Alan Gilbert wrote: > * Orit Wasserman (owasserm@redhat.com) wrote: >> It is better to fail migration in case of failure to >> allocate new cache item > > Does this actually fail migration or just drop back to sending an uncompressed > page? (I think the latter, and that's an even better result). > It fails the migration, if the users wants to disable compression it can do it and start migration again. >> Signed-off-by: Orit Wasserman >> --- >> arch_init.c | 4 +++- >> include/migration/page_cache.h | 4 +++- >> page_cache.c | 16 +++++++++++----- >> 3 files changed, 17 insertions(+), 7 deletions(-) >> >> diff --git a/arch_init.c b/arch_init.c >> index 806d096..0bfbc5a 100644 >> --- a/arch_init.c >> +++ b/arch_init.c >> @@ -284,7 +284,9 @@ static int save_xbzrle_page(QEMUFile *f, uint8_t *current_data, >> >> if (!cache_is_cached(XBZRLE.cache, current_addr)) { >> if (!last_stage) { >> - cache_insert(XBZRLE.cache, current_addr, current_data); >> + if (cache_insert(XBZRLE.cache, current_addr, current_data) == -1) { >> + return -1; >> + } >> } >> acct_info.xbzrle_cache_miss++; >> return -1; >> diff --git a/include/migration/page_cache.h b/include/migration/page_cache.h >> index 87894fe..d156f0d 100644 >> --- a/include/migration/page_cache.h >> +++ b/include/migration/page_cache.h >> @@ -60,11 +60,13 @@ uint8_t *get_cached_data(const PageCache *cache, uint64_t addr); >> * cache_insert: insert the page into the cache. the page cache >> * will dup the data on insert. the previous value will be overwritten >> * >> + * Returns -1 on error >> + * >> * @cache pointer to the PageCache struct >> * @addr: page address >> * @pdata: pointer to the page >> */ >> -void cache_insert(PageCache *cache, uint64_t addr, uint8_t *pdata); >> +int cache_insert(PageCache *cache, uint64_t addr, uint8_t *pdata); >> >> /** >> * cache_resize: resize the page cache. In case of size reduction the extra >> diff --git a/page_cache.c b/page_cache.c >> index 62a53f8..69e8329 100644 >> --- a/page_cache.c >> +++ b/page_cache.c >> @@ -150,7 +150,7 @@ uint8_t *get_cached_data(const PageCache *cache, uint64_t addr) >> return cache_get_by_addr(cache, addr)->it_data; >> } >> >> -void cache_insert(PageCache *cache, uint64_t addr, uint8_t *pdata) >> +int cache_insert(PageCache *cache, uint64_t addr, uint8_t *pdata) >> { >> >> CacheItem *it = NULL; >> @@ -161,16 +161,22 @@ void cache_insert(PageCache *cache, uint64_t addr, uint8_t *pdata) >> /* actual update of entry */ >> it = cache_get_by_addr(cache, addr); >> >> - /* free old cached data if any */ >> - g_free(it->it_data); >> - >> + /* allocate page */ >> if (!it->it_data) { >> cache->num_items++; >> + it->it_data = g_try_malloc(cache->page_size); >> + if (!it->it_data) { >> + DPRINTF("Error allocating page\n"); >> + return -1; >> + } > > It feels like it would have been correct to do the num_items++ after the > allocation test (although since the num_items doesn't seem to be used > anywhere that's not a show-stopper, but worth fixing sometime). > You are correct, I will move it after allocation. Orit >> } >> >> - it->it_data = g_memdup(pdata, cache->page_size); >> + memcpy(it->it_data, pdata, cache->page_size); >> + >> it->it_age = ++cache->max_item_age; >> it->it_addr = addr; >> + >> + return 0; >> } >> >> int64_t cache_resize(PageCache *cache, int64_t new_num_pages) >> -- >> 1.8.3.1 > > Reviewed-by: Dr. David Alan Gilbert > > Dave > -- > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK >