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authorSuren Baghdasaryan <surenb@google.com>2023-02-27 09:36:31 -0800
committerAndrew Morton <akpm@linux-foundation.org>2023-04-05 20:03:02 -0700
commit0d2ebf9c3f7822e7ba3e4792ea3b6b19aa2da34a (patch)
tree238c51ee2bbbe47ded831d364d90b56ad8b9b7a3 /kernel/fork.c
parent70d4cbc80c88251de0a5b3e8df3275901f1fa99a (diff)
mm/mmap: free vm_area_struct without call_rcu in exit_mmap
call_rcu() can take a long time when callback offloading is enabled. Its use in the vm_area_free can cause regressions in the exit path when multiple VMAs are being freed. Because exit_mmap() is called only after the last mm user drops its refcount, the page fault handlers can't be racing with it. Any other possible user like oom-reaper or process_mrelease are already synchronized using mmap_lock. Therefore exit_mmap() can free VMAs directly, without the use of call_rcu(). Expose __vm_area_free() and use it from exit_mmap() to avoid possible call_rcu() floods and performance regressions caused by it. Link: https://lkml.kernel.org/r/20230227173632.3292573-33-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'kernel/fork.c')
-rw-r--r--kernel/fork.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index 76fcc08984d4..f86f7e917954 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -480,7 +480,7 @@ struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig)
return new;
}
-static void __vm_area_free(struct vm_area_struct *vma)
+void __vm_area_free(struct vm_area_struct *vma)
{
free_anon_vma_name(vma);
kmem_cache_free(vm_area_cachep, vma);