The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x b15655b12ddca7ade09807f790bafb6fab61b50a # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2023052842-ability-badness-50c6@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
b15655b12ddc ("Revert "binder_alloc: add missing mmap_lock calls when using the VMA"") e66b77e50522 ("binder: rename alloc->vma_vm_mm to alloc->mm") 50e177c5bfd9 ("Merge 6.0-rc4 into char-misc-next")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From b15655b12ddca7ade09807f790bafb6fab61b50a Mon Sep 17 00:00:00 2001 From: Carlos Llamas cmllamas@google.com Date: Tue, 2 May 2023 20:12:17 +0000 Subject: [PATCH] Revert "binder_alloc: add missing mmap_lock calls when using the VMA"
This reverts commit 44e602b4e52f70f04620bbbf4fe46ecb40170bde.
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: 44e602b4e52f ("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
diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c index 55a3c3c2409f..92c814ec44fe 100644 --- a/drivers/android/binder_alloc.c +++ b/drivers/android/binder_alloc.c @@ -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; - } - - 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++; + 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++; + } } - -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);