diff options
| author | Michal Hocko <mhocko@suse.com> | 2022-12-16 14:45:37 -0500 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-01-18 17:12:41 -0800 |
| commit | e976936cfc66376fc740a3a476365273384ce1ce (patch) | |
| tree | 12c3547af7f4a0270a2afb925252a29162718d12 /mm/mempolicy.c | |
| parent | a5fd8390d2b2db15fd043b8bd571b536101222c2 (diff) | |
mm/mempolicy: do not duplicate policy if it is not applicable for set_mempolicy_home_node
set_mempolicy_home_node tries to duplicate a memory policy before checking
it whether it is applicable for the operation. There is no real reason
for doing that and it might actually be a pointless memory allocation and
deallocation exercise for MPOL_INTERLEAVE.
Not a big problem but we can do better. Simply check the policy before
acting on it.
Link: https://lkml.kernel.org/r/20221216194537.238047-2-mathieu.desnoyers@efficios.com
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/mempolicy.c')
| -rw-r--r-- | mm/mempolicy.c | 28 |
1 files changed, 12 insertions, 16 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 02c8a712282f..becf41e10076 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1489,7 +1489,7 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le { struct mm_struct *mm = current->mm; struct vm_area_struct *vma; - struct mempolicy *new; + struct mempolicy *new, *old; unsigned long vmstart; unsigned long vmend; unsigned long end; @@ -1521,31 +1521,27 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le return 0; mmap_write_lock(mm); for_each_vma_range(vmi, vma, end) { - vmstart = max(start, vma->vm_start); - vmend = min(end, vma->vm_end); - new = mpol_dup(vma_policy(vma)); - if (IS_ERR(new)) { - err = PTR_ERR(new); - break; - } - /* - * Only update home node if there is an existing vma policy - */ - if (!new) - continue; - /* * If any vma in the range got policy other than MPOL_BIND * or MPOL_PREFERRED_MANY we return error. We don't reset * the home node for vmas we already updated before. */ - if (new->mode != MPOL_BIND && new->mode != MPOL_PREFERRED_MANY) { - mpol_put(new); + old = vma_policy(vma); + if (!old) + continue; + if (old->mode != MPOL_BIND && old->mode != MPOL_PREFERRED_MANY) { err = -EOPNOTSUPP; break; } + new = mpol_dup(old); + if (IS_ERR(new)) { + err = PTR_ERR(new); + break; + } new->home_node = home_node; + vmstart = max(start, vma->vm_start); + vmend = min(end, vma->vm_end); err = mbind_range(mm, vmstart, vmend, new); mpol_put(new); if (err) |