From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: [PATCH take3] Memoryless nodes: use "node_memory_map" for cpuset mems_allowed validation From: Lee Schermerhorn In-Reply-To: References: <20070711182219.234782227@sgi.com> <20070711182250.005856256@sgi.com> Content-Type: text/plain Date: Tue, 24 Jul 2007 16:30:19 -0400 Message-Id: <1185309019.5649.69.camel@localhost> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter , Paul Jackson , Nishanth Aravamudan Cc: akpm@linux-foundation.org, kxr@sgi.com, linux-mm@kvack.org, KAMEZAWA Hiroyuki List-ID: Memoryless Nodes: use "node_memory_map" for cpusets - take 3 Against 2.6.22-rc6-mm1 atop Christoph Lameter's memoryless nodes series take 2: + replaced node_online_map in cpuset_current_mems_allowed() with node_states[N_MEMORY] + replaced node_online_map in cpuset_init_smp() with node_states[N_MEMORY] take 3: + fix up comments and top level cpuset tracking of nodes with memory [instead of on-line nodes]. + maybe I got them all this time? cpusets try to ensure that any node added to a cpuset's mems_allowed is on-line and contains memory. The assumption was that online nodes contained memory. Thus, it is possible to add memoryless nodes to a cpuset and then add tasks to this cpuset. This results in continuous series of oom-kill and apparent system hang. Change cpusets to use node_states[N_MEMORY] [a.k.a. node_memory_map] in place of node_online_map when vetting memories. Return error if admin attempts to write a non-empty mems_allowed node mask containing only memoryless-nodes. Signed-off-by: Lee Schermerhorn include/linux/cpuset.h | 2 - kernel/cpuset.c | 51 +++++++++++++++++++++++++++++++------------------ 2 files changed, 34 insertions(+), 19 deletions(-) Index: Linux/kernel/cpuset.c =================================================================== --- Linux.orig/kernel/cpuset.c 2007-07-24 11:24:56.000000000 -0400 +++ Linux/kernel/cpuset.c 2007-07-24 12:20:40.000000000 -0400 @@ -316,26 +316,26 @@ static void guarantee_online_cpus(const /* * Return in *pmask the portion of a cpusets's mems_allowed that - * are online. If none are online, walk up the cpuset hierarchy - * until we find one that does have some online mems. If we get - * all the way to the top and still haven't found any online mems, - * return node_online_map. + * are online, with memory. If none are online with memory, walk + * up the cpuset hierarchy until we find one that does have some + * online mems. If we get all the way to the top and still haven't + * found any online mems, return node_states[N_MEMORY]. * * One way or another, we guarantee to return some non-empty subset - * of node_online_map. + * of node_states[N_MEMORY]. * * Call with callback_mutex held. */ static void guarantee_online_mems(const struct cpuset *cs, nodemask_t *pmask) { - while (cs && !nodes_intersects(cs->mems_allowed, node_online_map)) + while (cs && !nodes_intersects(cs->mems_allowed, node_states[N_MEMORY])) cs = cs->parent; if (cs) - nodes_and(*pmask, cs->mems_allowed, node_online_map); + nodes_and(*pmask, cs->mems_allowed, node_states[N_MEMORY]); else - *pmask = node_online_map; - BUG_ON(!nodes_intersects(*pmask, node_online_map)); + *pmask = node_states[N_MEMORY]; + BUG_ON(!nodes_intersects(*pmask, node_states[N_MEMORY])); } /** @@ -606,7 +606,7 @@ static int update_nodemask(struct cpuset int retval; struct container_iter it; - /* top_cpuset.mems_allowed tracks node_online_map; it's read-only */ + /* top_cpuset.mems_allowed tracks node_states[N_MEMORY]; it's read-only */ if (cs == &top_cpuset) return -EACCES; @@ -623,8 +623,21 @@ static int update_nodemask(struct cpuset retval = nodelist_parse(buf, trialcs.mems_allowed); if (retval < 0) goto done; + if (!nodes_intersects(trialcs.mems_allowed, + node_states[N_MEMORY])) { + /* + * error if only memoryless nodes specified. + */ + retval = -ENOSPC; + goto done; + } } - nodes_and(trialcs.mems_allowed, trialcs.mems_allowed, node_online_map); + /* + * Exclude memoryless nodes. We know that trialcs.mems_allowed + * contains at least one node with memory. + */ + nodes_and(trialcs.mems_allowed, trialcs.mems_allowed, + node_states[N_MEMORY]); oldmem = cs->mems_allowed; if (nodes_equal(oldmem, trialcs.mems_allowed)) { retval = 0; /* Too easy - nothing to do */ @@ -1366,8 +1379,9 @@ static void guarantee_online_cpus_mems_i /* * The cpus_allowed and mems_allowed nodemasks in the top_cpuset track - * cpu_online_map and node_online_map. Force the top cpuset to track - * whats online after any CPU or memory node hotplug or unplug event. + * cpu_online_map and node_states[N_MEMORY]. Force the top cpuset to + * track what's online after any CPU or memory node hotplug or unplug + * event. * * To ensure that we don't remove a CPU or node from the top cpuset * that is currently in use by a child cpuset (which would violate @@ -1387,7 +1401,7 @@ static void common_cpu_mem_hotplug_unplu guarantee_online_cpus_mems_in_subtree(&top_cpuset); top_cpuset.cpus_allowed = cpu_online_map; - top_cpuset.mems_allowed = node_online_map; + top_cpuset.mems_allowed = node_states[N_MEMORY]; mutex_unlock(&callback_mutex); container_unlock(); @@ -1412,8 +1426,9 @@ static int cpuset_handle_cpuhp(struct no #ifdef CONFIG_MEMORY_HOTPLUG /* - * Keep top_cpuset.mems_allowed tracking node_online_map. - * Call this routine anytime after you change node_online_map. + * Keep top_cpuset.mems_allowed tracking node_states[N_MEMORY]. + * Call this routine anytime after you change + * node_states[N_MEMORY]. * See also the previous routine cpuset_handle_cpuhp(). */ @@ -1432,7 +1447,7 @@ void cpuset_track_online_nodes(void) void __init cpuset_init_smp(void) { top_cpuset.cpus_allowed = cpu_online_map; - top_cpuset.mems_allowed = node_online_map; + top_cpuset.mems_allowed = node_states[N_MEMORY]; hotcpu_notifier(cpuset_handle_cpuhp, 0); } @@ -1472,7 +1487,7 @@ void cpuset_init_current_mems_allowed(vo * * Description: Returns the nodemask_t mems_allowed of the cpuset * attached to the specified @tsk. Guaranteed to return some non-empty - * subset of node_online_map, even if this means going outside the + * subset of node_states[N_MEMORY], even if this means going outside the * tasks cpuset. **/ Index: Linux/include/linux/cpuset.h =================================================================== --- Linux.orig/include/linux/cpuset.h 2007-07-24 11:24:56.000000000 -0400 +++ Linux/include/linux/cpuset.h 2007-07-24 12:20:56.000000000 -0400 @@ -92,7 +92,7 @@ static inline nodemask_t cpuset_mems_all return node_possible_map; } -#define cpuset_current_mems_allowed (node_online_map) +#define cpuset_current_mems_allowed (node_states[N_MEMORY)) static inline void cpuset_init_current_mems_allowed(void) {} static inline void cpuset_update_task_memory_state(void) {} #define cpuset_nodes_subset_current_mems_allowed(nodes) (1) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . 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