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| author | Suren Baghdasaryan <surenb@google.com> | 2023-02-27 09:36:31 -0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-04-05 20:03:02 -0700 |
| commit | 0d2ebf9c3f7822e7ba3e4792ea3b6b19aa2da34a (patch) | |
| tree | 238c51ee2bbbe47ded831d364d90b56ad8b9b7a3 /kernel/capability.c | |
| parent | powerc/mm: try VMA lock-based page fault handling first (diff) | |
| download | linux-0d2ebf9c3f7822e7ba3e4792ea3b6b19aa2da34a.tar.gz linux-0d2ebf9c3f7822e7ba3e4792ea3b6b19aa2da34a.zip | |
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/capability.c')
0 files changed, 0 insertions, 0 deletions