From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sog-mx-3.v43.ch3.sourceforge.com ([172.29.43.193] helo=mx.sourceforge.net) by sfs-ml-3.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1VC8Ma-0007EH-Sb for ltp-list@lists.sourceforge.net; Wed, 21 Aug 2013 13:22:16 +0000 Received: from aserp1040.oracle.com ([141.146.126.69]) by sog-mx-3.v43.ch3.sourceforge.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.76) id 1VC8MZ-0002XD-P8 for ltp-list@lists.sourceforge.net; Wed, 21 Aug 2013 13:22:16 +0000 Message-ID: <5214BEFC.504@oracle.com> Date: Wed, 21 Aug 2013 17:22:04 +0400 From: Stanislav Kholmanskikh MIME-Version: 1.0 References: <52122141.3020005@oracle.com> <1377086098-32691-3-git-send-email-stanislav.kholmanskikh@oracle.com> <212598736.1836601.1377088154292.JavaMail.root@redhat.com> In-Reply-To: <212598736.1836601.1377088154292.JavaMail.root@redhat.com> Subject: Re: [LTP] [PATCH V2 3/3] lib/numa_helper.c: fix nodemask_size List-Id: Linux Test Project General Discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ltp-list-bounces@lists.sourceforge.net To: Jan Stancek Cc: vasily isaenko , ltp-list@lists.sourceforge.net On 08/21/2013 04:29 PM, Jan Stancek wrote: > > > > ----- Original Message ----- >> From: "Stanislav Kholmanskikh" >> To: ltp-list@lists.sourceforge.net >> Cc: "vasily isaenko" , jstancek@redhat.com >> Sent: Wednesday, 21 August, 2013 1:54:58 PM >> Subject: [PATCH V2 3/3] lib/numa_helper.c: fix nodemask_size >> >> Now nodemask_size is rounded up to the next multiple >> of sizeof(nodemask_t). > Hi, > > Why multiple of nodemask_t? It can be quite large. Hi. As nodemask is a pointer to nodemask_t type, so it should point to memory areas multiple of sizeof(nodemask_t). Isn't it? > >> Signed-off-by: Stanislav Kholmanskikh >> --- >> testcases/kernel/lib/numa_helper.c | 6 +++--- >> 1 files changed, 3 insertions(+), 3 deletions(-) >> >> diff --git a/testcases/kernel/lib/numa_helper.c >> b/testcases/kernel/lib/numa_helper.c >> index 4157816..9151583 100644 >> --- a/testcases/kernel/lib/numa_helper.c >> +++ b/testcases/kernel/lib/numa_helper.c >> @@ -60,7 +60,7 @@ unsigned long get_max_node(void) >> #if HAVE_NUMA_H >> static void get_nodemask_allnodes(nodemask_t * nodemask, unsigned long >> max_node) >> { >> - unsigned long nodemask_size = max_node / 8 + 1; >> + unsigned long nodemask_size = ALIGN(max_node, sizeof(nodemask_t)*8) / 8; > Because mask is passed as parameter, we should respect max_node and > clear only up to byte which holds max_node. So I think we should align > to next byte only: > > unsigned long nodemask_size = ALIGN(max_node, 8) / 8; I agree but I'm not sure how bytes comprising nodemask_t are handled. If they are handled in an endianness-dependant way then your approach will work only on little-endian systems. So I decided to clear entire region. The same for filter_nodemask_mem. > >> int i; >> char fn[64]; >> struct stat st; >> @@ -76,7 +76,7 @@ static void get_nodemask_allnodes(nodemask_t * nodemask, >> unsigned long max_node) >> static int filter_nodemask_mem(nodemask_t * nodemask, unsigned long >> max_node) >> { >> #if MPOL_F_MEMS_ALLOWED >> - unsigned long nodemask_size = max_node / 8 + 1; >> + unsigned long nodemask_size = ALIGN(max_node, sizeof(nodemask_t)*8) / 8; > Same as above: > unsigned long nodemask_size = ALIGN(max_node, 8) / 8; > >> memset(nodemask, 0, nodemask_size); >> /* >> * avoid numa_get_mems_allowed(), because of bug in getpol() >> @@ -165,7 +165,7 @@ int get_allowed_nodes_arr(int flag, int *num_nodes, int >> **nodes) >> >> #if HAVE_NUMA_H >> unsigned long max_node = get_max_node(); >> - unsigned long nodemask_size = max_node / 8 + 1; >> + unsigned long nodemask_size = ALIGN(max_node, sizeof(nodemask_t)*8) / 8; > This function allocates the nodemask, so we can align to as much as we need. > I'd expect this to be same as in migrate_pages, align to next long: > > unsigned long nodemask_size = ALIGN(max_node / 8, sizeof(long)); This formula may give incorrect results. For example, if max_mode = 66 and sizeof(long) = 8, then ALIGN(max_node / 8, sizeof(long)) will output 8 and we will lost 2 bits. The correct output should be 16. I think as max_node contains number of bits so we should align it on sizeof(long)*8 boundary and after that divide the final result by 8. > Regards, > Jan > >> >> nodemask = malloc(nodemask_size); >> if (nodes) >> -- >> 1.7.1 >> >> ------------------------------------------------------------------------------ Introducing Performance Central, a new site from SourceForge and AppDynamics. Performance Central is your source for news, insights, analysis and resources for efficient Application Performance Management. Visit us today! http://pubads.g.doubleclick.net/gampad/clk?id=48897511&iu=/4140/ostg.clktrk _______________________________________________ Ltp-list mailing list Ltp-list@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/ltp-list