lkml.org 
[lkml]   [2023]   [May]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH net-next 06/11] net: page_pool: avoid calling no-op externals when possible
From
Date
On 2023/5/18 12:08, Jakub Kicinski wrote:
> On Tue, 16 May 2023 18:18:36 +0200 Alexander Lobakin wrote:
>> + /* Try to avoid calling no-op syncs */
>> + pool->p.flags |= PP_FLAG_DMA_MAYBE_SYNC;
>> + pool->p.flags &= ~PP_FLAG_DMA_SYNC_DEV;
>> }
>>
>> if (PAGE_POOL_DMA_USE_PP_FRAG_COUNT &&
>> @@ -323,6 +327,12 @@ static bool page_pool_dma_map(struct page_pool *pool, struct page *page)
>>
>> page_pool_set_dma_addr(page, dma);
>>
>> + if ((pool->p.flags & PP_FLAG_DMA_MAYBE_SYNC) &&
>> + dma_need_sync(pool->p.dev, dma)) {
>> + pool->p.flags |= PP_FLAG_DMA_SYNC_DEV;
>> + pool->p.flags &= ~PP_FLAG_DMA_MAYBE_SYNC;
>> + }
>
> is it just me or does it feel cleaner to allocate a page at init,
> and throw it into the cache, rather than adding a condition to a
> fast(ish) path?

Is dma_need_sync() not reliable until a dma map is called?
Is there any reason why not just clear PP_FLAG_DMA_SYNC_DEV if
dma_need_sync() is false without introducing the PP_FLAG_DMA_MAYBE_SYNC
flag?

>
> .
>

\
 
 \ /
  Last update: 2023-05-18 06:55    [W:0.135 / U:0.164 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site