From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753698Ab3LND1l (ORCPT ); Fri, 13 Dec 2013 22:27:41 -0500 Received: from mail-pa0-f50.google.com ([209.85.220.50]:51682 "EHLO mail-pa0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753411Ab3LND07 (ORCPT ); Fri, 13 Dec 2013 22:26:59 -0500 From: John Stultz To: LKML Cc: Greg KH , Android Kernel Team , Sumit Semwal , Jesse Barker , Colin Cross , John Stultz Subject: [PATCH 101/115] ion: optimize ion_heap_buffer_zero Date: Fri, 13 Dec 2013 19:26:21 -0800 Message-Id: <1386991595-6251-9-git-send-email-john.stultz@linaro.org> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1386991595-6251-1-git-send-email-john.stultz@linaro.org> References: <1386973529-4884-1-git-send-email-john.stultz@linaro.org> <1386991595-6251-1-git-send-email-john.stultz@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Colin Cross ion_heap_buffer_zero can spend a long time in unmap_kernel_range if it has to broadcast a tlb flush to every cpu for every page. Modify it to batch pages into a larger region to clear using a single mapping. This may cause the mapping size to change if the buffer size is not a multiple of the mapping size, so switch to allocating the address space for each chunk. This allows us to use vm_map_ram to handle the allocation and mapping together. The number of pages to zero using a single mapping is set to 32 to hit the fastpath in vm_map_ram. Signed-off-by: Colin Cross Signed-off-by: John Stultz --- drivers/staging/android/ion/ion_heap.c | 36 +++++++++++++++++++++------------- 1 file changed, 22 insertions(+), 14 deletions(-) diff --git a/drivers/staging/android/ion/ion_heap.c b/drivers/staging/android/ion/ion_heap.c index 0a5cea0..ce31561 100644 --- a/drivers/staging/android/ion/ion_heap.c +++ b/drivers/staging/android/ion/ion_heap.c @@ -100,40 +100,48 @@ int ion_heap_map_user(struct ion_heap *heap, struct ion_buffer *buffer, return 0; } +static int ion_heap_clear_pages(struct page **pages, int num, pgprot_t pgprot) +{ + void *addr = vm_map_ram(pages, num, -1, pgprot); + if (!addr) + return -ENOMEM; + memset(addr, 0, PAGE_SIZE * num); + vm_unmap_ram(addr, num); + + return 0; +} + int ion_heap_buffer_zero(struct ion_buffer *buffer) { struct sg_table *table = buffer->sg_table; pgprot_t pgprot; struct scatterlist *sg; - struct vm_struct *vm_struct; int i, j, ret = 0; + struct page *pages[32]; + int k = 0; if (buffer->flags & ION_FLAG_CACHED) pgprot = PAGE_KERNEL; else pgprot = pgprot_writecombine(PAGE_KERNEL); - vm_struct = get_vm_area(PAGE_SIZE, VM_ALLOC); - if (!vm_struct) - return -ENOMEM; - for_each_sg(table->sgl, sg, table->nents, i) { struct page *page = sg_page(sg); unsigned long len = sg->length; for (j = 0; j < len / PAGE_SIZE; j++) { - struct page *sub_page = page + j; - struct page **pages = &sub_page; - ret = map_vm_area(vm_struct, pgprot, &pages); - if (ret) - goto end; - memset(vm_struct->addr, 0, PAGE_SIZE); - unmap_kernel_range((unsigned long)vm_struct->addr, - PAGE_SIZE); + pages[k++] = page + j; + if (k == ARRAY_SIZE(pages)) { + ret = ion_heap_clear_pages(pages, k, pgprot); + if (ret) + goto end; + k = 0; + } } + if (k) + ret = ion_heap_clear_pages(pages, k, pgprot); } end: - free_vm_area(vm_struct); return ret; } -- 1.8.3.2