Hi Vlastimil, On 2017/12/1 23:18, Vlastimil Babka wrote: > On 12/01/2017 10:55 AM, Yisheng Xie wrote: >> As in manpage of migrate_pages, the errno should be set to EINVAL when >> none of the node IDs specified by new_nodes are on-line and allowed by the >> process's current cpuset context, or none of the specified nodes contain >> memory. However, when test by following case: >> >> new_nodes = 0; >> old_nodes = 0xf; >> ret = migrate_pages(pid, old_nodes, new_nodes, MAX); >> >> The ret will be 0 and no errno is set. As the new_nodes is empty, we >> should expect EINVAL as documented. >> >> To fix the case like above, this patch check whether target nodes AND >> current task_nodes is empty, and then check whether AND >> node_states[N_MEMORY] is empty. >> >> Meanwhile,this patch also remove the check of EPERM on CAP_SYS_NICE. >> The caller of migrate_pages should be able to migrate the target process >> pages anywhere the caller can allocate memory, if the caller can access >> the mm_struct. >> >> Signed-off-by: Yisheng Xie <xieyisheng1@xxxxxxxxxx> >> Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx> >> Cc: Chris Salls <salls@xxxxxxxxxxx> >> Cc: Christopher Lameter <cl@xxxxxxxxx> >> Cc: David Rientjes <rientjes@xxxxxxxxxx> >> Cc: Ingo Molnar <mingo@xxxxxxxxxx> >> Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> >> Cc: Tan Xiaojun <tanxiaojun@xxxxxxxxxx> >> Cc: Vlastimil Babka <vbabka@xxxxxxx> >> --- >> v3: >> * check whether node is empty after AND current task node, and then nodes >> which have memory >> v4: >> * remove the check of EPERM on CAP_SYS_NICE. >> >> Hi Vlastimil and Christopher, >> >> Could you please help to review this version? > > Hi, I think we should stay with v3 after all. What I missed when > reviewing it, is that the EPERM check is for cpuset_mems_allowed(task) > and in v3 you add EINVAL check for cpuset_mems_allowed(current), which > may not be the same, and the intention of CAP_SYS_NICE is not whether we > can bypass our own cpuset, but whether we can bypass the target task's > cpuset. Sorry for the confusion. Ok, so please ignore this version. Thanks Yisheng Xie > > > . > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
