From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx139.postini.com [74.125.245.139]) by kanga.kvack.org (Postfix) with SMTP id AAB286B005A for ; Mon, 12 Nov 2012 04:48:10 -0500 (EST) Message-ID: <50A0C5D2.7000806@web.de> Date: Mon, 12 Nov 2012 10:48:02 +0100 From: Soeren Moch MIME-Version: 1.0 Subject: Re: [PATCH] mm: dmapool: use provided gfp flags for all dma_alloc_coherent() calls References: <1352356737-14413-1-git-send-email-m.szyprowski@samsung.com> <20121111172243.GB821@lunn.ch> In-Reply-To: <20121111172243.GB821@lunn.ch> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Lunn , Marek Szyprowski Cc: linux-arm-kernel@lists.infradead.org, linaro-mm-sig@lists.linaro.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Kyungmin Park , Arnd Bergmann , Thomas Petazzoni , Sebastian Hesselbarth On 11.11.2012 18:22, Andrew Lunn wrote: > On Thu, Nov 08, 2012 at 07:38:57AM +0100, Marek Szyprowski wrote: >> dmapool always calls dma_alloc_coherent() with GFP_ATOMIC flag, regardless >> the flags provided by the caller. This causes excessive pruning of >> emergency memory pools without any good reason. This patch changes the code >> to correctly use gfp flags provided by the dmapool caller. This should >> solve the dmapool usage on ARM architecture, where GFP_ATOMIC DMA >> allocations can be served only from the special, very limited memory pool. >> >> Reported-by: Soren Moch Please use Reported-by: Soeren Moch >> Reported-by: Thomas Petazzoni >> Signed-off-by: Marek Szyprowski > > Tested-by: Andrew Lunn > > I tested this on a Kirkwood QNAP after removing the call to > init_dma_coherent_pool_size(). > > Andrew Tested-by: Soeren Moch Now I had a chance to test this patch on my Kirkwood guruplug system with linux-3.6.6 . It is running much better now, but with the original 256K coherent pool size I still see errors after several hours of runtime: Nov 12 09:42:32 guru kernel: ERROR: 256 KiB atomic DMA coherent pool is too small! Nov 12 09:42:32 guru kernel: Please increase it with coherent_pool= kernel parameter! Soeren >> --- >> mm/dmapool.c | 27 +++++++-------------------- >> 1 file changed, 7 insertions(+), 20 deletions(-) >> >> diff --git a/mm/dmapool.c b/mm/dmapool.c >> index c5ab33b..86de9b2 100644 >> --- a/mm/dmapool.c >> +++ b/mm/dmapool.c >> @@ -62,8 +62,6 @@ struct dma_page { /* cacheable header for 'allocation' bytes */ >> unsigned int offset; >> }; >> >> -#define POOL_TIMEOUT_JIFFIES ((100 /* msec */ * HZ) / 1000) >> - >> static DEFINE_MUTEX(pools_lock); >> >> static ssize_t >> @@ -227,7 +225,6 @@ static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags) >> memset(page->vaddr, POOL_POISON_FREED, pool->allocation); >> #endif >> pool_initialise_page(pool, page); >> - list_add(&page->page_list, &pool->page_list); >> page->in_use = 0; >> page->offset = 0; >> } else { >> @@ -315,30 +312,21 @@ void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags, >> might_sleep_if(mem_flags & __GFP_WAIT); >> >> spin_lock_irqsave(&pool->lock, flags); >> - restart: >> list_for_each_entry(page, &pool->page_list, page_list) { >> if (page->offset < pool->allocation) >> goto ready; >> } >> - page = pool_alloc_page(pool, GFP_ATOMIC); >> - if (!page) { >> - if (mem_flags & __GFP_WAIT) { >> - DECLARE_WAITQUEUE(wait, current); >> >> - __set_current_state(TASK_UNINTERRUPTIBLE); >> - __add_wait_queue(&pool->waitq, &wait); >> - spin_unlock_irqrestore(&pool->lock, flags); >> + /* pool_alloc_page() might sleep, so temporarily drop &pool->lock */ >> + spin_unlock_irqrestore(&pool->lock, flags); >> >> - schedule_timeout(POOL_TIMEOUT_JIFFIES); >> + page = pool_alloc_page(pool, mem_flags); >> + if (!page) >> + return NULL; >> >> - spin_lock_irqsave(&pool->lock, flags); >> - __remove_wait_queue(&pool->waitq, &wait); >> - goto restart; >> - } >> - retval = NULL; >> - goto done; >> - } >> + spin_lock_irqsave(&pool->lock, flags); >> >> + list_add(&page->page_list, &pool->page_list); >> ready: >> page->in_use++; >> offset = page->offset; >> @@ -348,7 +336,6 @@ void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags, >> #ifdef DMAPOOL_DEBUG >> memset(retval, POOL_POISON_ALLOCATED, pool->size); >> #endif >> - done: >> spin_unlock_irqrestore(&pool->lock, flags); >> return retval; >> } >> -- >> 1.7.9.5 >> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org