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binder: use per-vma lock in page reclaiming

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Use per-vma locking in the shrinker's callback when reclaiming pages,
similar to the page installation logic. This minimizes contention with
unrelated vmas improving performance. The mmap_sem is still acquired if
the per-vma lock cannot be obtained.

Cc: Suren Baghdasaryan <surenb@google.com>
Suggested-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Link: https://lore.kernel.org/r/20241210143114.661252-10-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Carlos Llamas 2024-12-10 14:31:05 +00:00 • committed by Greg Kroah-Hartman
parent 978ce3ed70
commit 95bc2d4a90
1 changed files with 22 additions and 7 deletions
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23
drivers/android/binder_alloc.c
View file

@ -1143,19 +1143,28 @@ enum lru_status binder_alloc_free_page(struct list_head *item,
struct vm_area_struct *vma;
struct page *page_to_free;
unsigned long page_addr;
int mm_locked = 0;
size_t index;
if (!mmget_not_zero(mm))
goto err_mmget;
if (!mmap_read_trylock(mm))
goto err_mmap_read_lock_failed;
if (!mutex_trylock(&alloc->mutex))
goto err_get_alloc_mutex_failed;
index = mdata->page_index;
page_addr = alloc->vm_start + index * PAGE_SIZE;
/* attempt per-vma lock first */
vma = lock_vma_under_rcu(mm, page_addr);
if (!vma) {
/* fall back to mmap_lock */
if (!mmap_read_trylock(mm))
goto err_mmap_read_lock_failed;
mm_locked = 1;
vma = vma_lookup(mm, page_addr);
}
if (!mutex_trylock(&alloc->mutex))
goto err_get_alloc_mutex_failed;
/*
* Since a binder_alloc can only be mapped once, we ensure
* the vma corresponds to this mapping by checking whether
@ -1183,7 +1192,10 @@ enum lru_status binder_alloc_free_page(struct list_head *item,
}
mutex_unlock(&alloc->mutex);
if (mm_locked)
mmap_read_unlock(mm);
else
vma_end_read(vma);
mmput_async(mm);
binder_free_page(page_to_free);
@ -1192,7 +1204,10 @@ enum lru_status binder_alloc_free_page(struct list_head *item,
err_invalid_vma:
mutex_unlock(&alloc->mutex);
err_get_alloc_mutex_failed:
if (mm_locked)
mmap_read_unlock(mm);
else
vma_end_read(vma);
err_mmap_read_lock_failed:
mmput_async(mm);
err_mmget: