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Revert "binder_alloc: add missing mmap_lock calls when using the VMA"

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commit b15655b12ddca7ade09807f790bafb6fab61b50a upstream.

This reverts commit 44e602b4e5.

This caused a performance regression particularly when pages are getting
reclaimed. We don't need to acquire the mmap_lock to determine when the
binder buffer has been fully initialized. A subsequent patch will bring
back the lockless approach for this.

[cmllamas: resolved trivial conflicts with renaming of alloc->mm]

Fixes: 44e602b4e5 ("binder_alloc: add missing mmap_lock calls when using the VMA")
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Link: https://lore.kernel.org/r/20230502201220.1756319-1-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Carlos Llamas 2023-05-02 20:12:17 +00:00 committed by Greg Kroah-Hartman
parent 8069bcaa5b
commit 7e6b854854
1 changed files with 10 additions and 21 deletions
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31
drivers/android/binder_alloc.c
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@ -380,15 +380,12 @@ static struct binder_buffer *binder_alloc_new_buf_locked(
size_t size, data_offsets_size;
int ret;
mmap_read_lock(alloc->mm);
if (!binder_alloc_get_vma(alloc)) {
mmap_read_unlock(alloc->mm);
binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
"%d: binder_alloc_buf, no vma\n",
alloc->pid);
return ERR_PTR(-ESRCH);
}
mmap_read_unlock(alloc->mm);
data_offsets_size = ALIGN(data_size, sizeof(void *)) +
ALIGN(offsets_size, sizeof(void *));
@ -916,25 +913,17 @@ void binder_alloc_print_pages(struct seq_file *m,
* Make sure the binder_alloc is fully initialized, otherwise we might
* read inconsistent state.
*/
mmap_read_lock(alloc->mm);
if (binder_alloc_get_vma(alloc) == NULL) {
mmap_read_unlock(alloc->mm);
goto uninitialized;
if (binder_alloc_get_vma(alloc) != NULL) {
for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
page = &alloc->pages[i];
if (!page->page_ptr)
free++;
else if (list_empty(&page->lru))
active++;
else
lru++;
}
}
mmap_read_unlock(alloc->mm);
for (i = 0; i < alloc->buffer_size / PAGE_SIZE; i++) {
page = &alloc->pages[i];
if (!page->page_ptr)
free++;
else if (list_empty(&page->lru))
active++;
else
lru++;
}
uninitialized:
mutex_unlock(&alloc->mutex);
seq_printf(m, " pages: %d:%d:%d\n", active, lru, free);
seq_printf(m, " pages high watermark: %zu\n", alloc->pages_high);