Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964954AbVKADOD (ORCPT ); Mon, 31 Oct 2005 22:14:03 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964956AbVKADNu (ORCPT ); Mon, 31 Oct 2005 22:13:50 -0500 Received: from omx1-ext.sgi.com ([192.48.179.11]:6829 "EHLO omx1.americas.sgi.com") by vger.kernel.org with ESMTP id S964954AbVKADNj (ORCPT ); Mon, 31 Oct 2005 22:13:39 -0500 Date: Mon, 31 Oct 2005 19:13:05 -0800 (PST) From: Christoph Lameter To: torvalds@osdl.org Cc: akpm@osdl.org, Marcelo Tosatti , Mike Kravetz , Ray Bryant , Lee Schermerhorn , linux-kernel@vger.kernel.org, Christoph Lameter , Magnus Damm , Paul Jackson , Dave Hansen , KAMEZAWA Hiroyuki Message-Id: <20051101031305.12488.1224.sendpatchset@schroedinger.engr.sgi.com> In-Reply-To: <20051101031239.12488.76816.sendpatchset@schroedinger.engr.sgi.com> References: <20051101031239.12488.76816.sendpatchset@schroedinger.engr.sgi.com> Subject: [PATCH 5/5] Swap Migration V5: sys_migrate_pages interface Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10031 Lines: 260 sys_migrate_pages implementation using swap based page migration This is the original API proposed by Ray Bryant in his posts during the first half of 2005 on linux-mm@kvack.org and linux-kernel@vger.kernel.org. The intend of sys_migrate is to migrate memory of a process. A process may have migrated to another node. Memory was allocated optimally for the prior context. sys_migrate_pages allows to shift the memory to the new node. sys_migrate_pages is also useful if the processes available memory nodes have changed through cpuset operations to manually move the processes memory. Paul Jackson is working on an automated mechanism that will allow an automatic migration if the cpuset of a process is changed. However, a user may decide to manually control the migration. This implementation is put into the policy layer since it uses concepts and functions that are also needed for mbind and friends. The patch also provides a do_migrate_pages function that may be useful for cpusets to automatically move memory. sys_migrate_pages does not modify policies in contrast to Ray's implementation. The current code here is based on the swap based page migration capability and thus not able to preserve the physical layout relative to it containing nodeset (which may be a cpuset). When direct page migration becomes available then the implementation needs to be changed to do a isomorphic move of pages between different nodesets. The current implementation simply evicts all pages in source nodeset that are not in the target nodeset. Patch supports ia64, i386, x86_64 and ppc64. Patch not tested on ppc64. Changes V4->V5: - Follow Paul's suggestion to make parameters const. Changes V3->V4: - Add Ray's permissions check based on check_kill_permission(). Signed-off-by: Christoph Lameter Index: linux-2.6.14-rc5-mm1/mm/mempolicy.c =================================================================== --- linux-2.6.14-rc5-mm1.orig/mm/mempolicy.c 2005-10-31 18:49:32.000000000 -0800 +++ linux-2.6.14-rc5-mm1/mm/mempolicy.c 2005-10-31 18:50:03.000000000 -0800 @@ -631,11 +631,41 @@ long do_get_mempolicy(int *policy, nodem } /* + * For now migrate_pages simply swaps out the pages from nodes that are in + * the source set but not in the target set. In the future, we would + * want a function that moves pages between the two nodesets in such + * a way as to preserve the physical layout as much as possible. + * + * Returns the number of page that could not be moved. + */ +int do_migrate_pages(struct mm_struct *mm, + const nodemask_t *from_nodes, const nodemask_t *to_nodes, int flags) +{ + LIST_HEAD(pagelist); + int count = 0; + nodemask_t nodes; + + nodes_andnot(nodes, *from_nodes, *to_nodes); + nodes_complement(nodes, nodes); + + down_read(&mm->mmap_sem); + check_range(mm, mm->mmap->vm_start, TASK_SIZE, &nodes, + flags | MPOL_MF_DISCONTIG_OK, &pagelist); + if (!list_empty(&pagelist)) { + migrate_pages(&pagelist, NULL); + if (!list_empty(&pagelist)) + count = putback_lru_pages(&pagelist); + } + up_read(&mm->mmap_sem); + return count; +} + +/* * User space interface with variable sized bitmaps for nodelists. */ /* Copy a node mask from user space. */ -static int get_nodes(nodemask_t *nodes, unsigned long __user *nmask, +static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask, unsigned long maxnode) { unsigned long k; @@ -724,6 +754,67 @@ asmlinkage long sys_set_mempolicy(int mo return do_set_mempolicy(mode, &nodes); } +/* Macro needed until Paul implements this function in kernel/cpusets.c */ +#define cpuset_mems_allowed(task) node_online_map + +asmlinkage long sys_migrate_pages(pid_t pid, unsigned long maxnode, + const unsigned long __user *old_nodes, + const unsigned long __user *new_nodes) +{ + struct mm_struct *mm; + struct task_struct *task; + nodemask_t old; + nodemask_t new; + nodemask_t task_nodes; + int err; + + err = get_nodes(&old, old_nodes, maxnode); + if (err) + return err; + + err = get_nodes(&new, new_nodes, maxnode); + if (err) + return err; + + /* Find the mm_struct */ + read_lock(&tasklist_lock); + task = pid ? find_task_by_pid(pid) : current; + if (!task) { + read_unlock(&tasklist_lock); + return -ESRCH; + } + mm = get_task_mm(task); + read_unlock(&tasklist_lock); + + if (!mm) + return -EINVAL; + + /* + * Permissions check like for signals. + * See check_kill_permission() + */ + if ((current->euid ^ task->suid) && (current->euid ^ task->uid) && + (current->uid ^ task->suid) && (current->uid ^ task->uid) && + !capable(CAP_SYS_ADMIN)) { + err = -EPERM; + goto out; + } + + task_nodes = cpuset_mems_allowed(task); + /* Is the user allowed to access the target nodes? */ + if (!nodes_subset(new, task_nodes) && + !capable(CAP_SYS_ADMIN)) { + err= -EPERM; + goto out; + } + + err = do_migrate_pages(mm, &old, &new, MPOL_MF_MOVE); +out: + mmput(mm); + return err; +} + + /* Retrieve NUMA policy */ asmlinkage long sys_get_mempolicy(int __user *policy, unsigned long __user *nmask, Index: linux-2.6.14-rc5-mm1/kernel/sys_ni.c =================================================================== --- linux-2.6.14-rc5-mm1.orig/kernel/sys_ni.c 2005-10-19 23:23:05.000000000 -0700 +++ linux-2.6.14-rc5-mm1/kernel/sys_ni.c 2005-10-31 18:50:03.000000000 -0800 @@ -82,6 +82,7 @@ cond_syscall(compat_sys_socketcall); cond_syscall(sys_inotify_init); cond_syscall(sys_inotify_add_watch); cond_syscall(sys_inotify_rm_watch); +cond_syscall(sys_migrate_pages); /* arch-specific weak syscall entries */ cond_syscall(sys_pciconfig_read); Index: linux-2.6.14-rc5-mm1/arch/ia64/kernel/entry.S =================================================================== --- linux-2.6.14-rc5-mm1.orig/arch/ia64/kernel/entry.S 2005-10-19 23:23:05.000000000 -0700 +++ linux-2.6.14-rc5-mm1/arch/ia64/kernel/entry.S 2005-10-31 18:50:03.000000000 -0800 @@ -1600,5 +1600,6 @@ sys_call_table: data8 sys_inotify_init data8 sys_inotify_add_watch data8 sys_inotify_rm_watch + data8 sys_migrate_pages .org sys_call_table + 8*NR_syscalls // guard against failures to increase NR_syscalls Index: linux-2.6.14-rc5-mm1/include/asm-ia64/unistd.h =================================================================== --- linux-2.6.14-rc5-mm1.orig/include/asm-ia64/unistd.h 2005-10-31 14:11:01.000000000 -0800 +++ linux-2.6.14-rc5-mm1/include/asm-ia64/unistd.h 2005-10-31 18:50:03.000000000 -0800 @@ -269,12 +269,12 @@ #define __NR_inotify_init 1277 #define __NR_inotify_add_watch 1278 #define __NR_inotify_rm_watch 1279 - +#define __NR_migrate_pages 1280 #ifdef __KERNEL__ #include -#define NR_syscalls 256 /* length of syscall table */ +#define NR_syscalls 257 /* length of syscall table */ #define __ARCH_WANT_SYS_RT_SIGACTION Index: linux-2.6.14-rc5-mm1/arch/ppc64/kernel/misc.S =================================================================== --- linux-2.6.14-rc5-mm1.orig/arch/ppc64/kernel/misc.S 2005-10-31 14:10:56.000000000 -0800 +++ linux-2.6.14-rc5-mm1/arch/ppc64/kernel/misc.S 2005-10-31 18:50:03.000000000 -0800 @@ -1581,3 +1581,4 @@ _GLOBAL(sys_call_table) .llong .sys_inotify_init /* 275 */ .llong .sys_inotify_add_watch .llong .sys_inotify_rm_watch + .llong .sys_migrate_pages Index: linux-2.6.14-rc5-mm1/arch/i386/kernel/syscall_table.S =================================================================== --- linux-2.6.14-rc5-mm1.orig/arch/i386/kernel/syscall_table.S 2005-10-19 23:23:05.000000000 -0700 +++ linux-2.6.14-rc5-mm1/arch/i386/kernel/syscall_table.S 2005-10-31 18:50:03.000000000 -0800 @@ -294,3 +294,5 @@ ENTRY(sys_call_table) .long sys_inotify_init .long sys_inotify_add_watch .long sys_inotify_rm_watch + .long sys_migrate_pages + Index: linux-2.6.14-rc5-mm1/include/asm-x86_64/unistd.h =================================================================== --- linux-2.6.14-rc5-mm1.orig/include/asm-x86_64/unistd.h 2005-10-31 14:11:01.000000000 -0800 +++ linux-2.6.14-rc5-mm1/include/asm-x86_64/unistd.h 2005-10-31 18:50:03.000000000 -0800 @@ -571,8 +571,10 @@ __SYSCALL(__NR_inotify_init, sys_inotify __SYSCALL(__NR_inotify_add_watch, sys_inotify_add_watch) #define __NR_inotify_rm_watch 255 __SYSCALL(__NR_inotify_rm_watch, sys_inotify_rm_watch) +#define __NR_migrate_pages 256 +__SYSCALL(__NR_migrate_pages, sys_migrate_pages) -#define __NR_syscall_max __NR_inotify_rm_watch +#define __NR_syscall_max __NR_migrate_pages #ifndef __NO_STUBS /* user-visible error numbers are in the range -1 - -4095 */ Index: linux-2.6.14-rc5-mm1/include/linux/syscalls.h =================================================================== --- linux-2.6.14-rc5-mm1.orig/include/linux/syscalls.h 2005-10-31 14:11:01.000000000 -0800 +++ linux-2.6.14-rc5-mm1/include/linux/syscalls.h 2005-10-31 18:50:03.000000000 -0800 @@ -511,5 +511,7 @@ asmlinkage long sys_ioprio_set(int which asmlinkage long sys_ioprio_get(int which, int who); asmlinkage long sys_set_mempolicy(int mode, unsigned long __user *nmask, unsigned long maxnode); +asmlinkage long sys_migrate_pages(pid_t pid, unsigned long maxnode, + const unsigned long __user *from, const unsigned long __user *to); #endif Index: linux-2.6.14-rc5-mm1/include/linux/mempolicy.h =================================================================== --- linux-2.6.14-rc5-mm1.orig/include/linux/mempolicy.h 2005-10-31 18:47:59.000000000 -0800 +++ linux-2.6.14-rc5-mm1/include/linux/mempolicy.h 2005-10-31 18:50:03.000000000 -0800 @@ -158,6 +158,9 @@ extern void numa_default_policy(void); extern void numa_policy_init(void); extern struct mempolicy default_policy; +int do_migrate_pages(struct mm_struct *mm, + const nodemask_t *from_nodes, const nodemask_t *to_nodes, int flags); + #else struct mempolicy {}; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/