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UPSTREAM: 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>

Bug: 451083029
Bug: 410746221
(cherry picked from commit 95bc2d4a9020efcd7858c91e68e9f4e842e3e8c8)
Change-Id: I11d07a05e06f837dcf68df763b2eb8cc484a8d7e
Signed-off-by: Carlos Llamas <cmllamas@google.com>
This commit is contained in:
Carlos Llamas
2024-12-10 14:31:05 +00:00
parent 0bc6341f8c
commit 49b52c1a99
1 changed files with 22 additions and 7 deletions
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drivers/android/binder_alloc.c
+22 -7
View File
@@ -1156,19 +1156,28 @@ 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->buffer + index * PAGE_SIZE;
vma = vma_lookup(mm, page_addr);
/* 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
@@ -1196,7 +1205,10 @@ enum lru_status binder_alloc_free_page(struct list_head *item,
}
mutex_unlock(&alloc->mutex);
mmap_read_unlock(mm);
if (mm_locked)
mmap_read_unlock(mm);
else
vma_end_read(vma);
mmput_async(mm);
binder_free_page(page_to_free);
@@ -1206,7 +1218,10 @@ enum lru_status binder_alloc_free_page(struct list_head *item,
err_invalid_vma:
mutex_unlock(&alloc->mutex);
err_get_alloc_mutex_failed:
mmap_read_unlock(mm);
if (mm_locked)
mmap_read_unlock(mm);
else
vma_end_read(vma);
err_mmap_read_lock_failed:
mmput_async(mm);
err_mmget: