Messages in this thread | | | Date | Wed, 17 Aug 2022 13:32:42 +0100 | Subject | Re: [PATCH 1/3] dma-pool: factor out a calculate_pool_size helper | From | Robin Murphy <> |
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On 2022-08-17 07:06, Christoph Hellwig wrote: > Add a helper to calculate the pool size from dma_atomic_pool_init, > and fix up the last max_t to use the proper type.
Hmm, both atomic_pool_size and the argument to __dma_atomic_pool_init() where this gets directly passed later are size_t, not to mention that the function name says we're calculating a size, so I'd say size_t *is* the proper type to return here.
> Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > kernel/dma/pool.c | 17 ++++++++++++----- > 1 file changed, 12 insertions(+), 5 deletions(-) > > diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c > index 4d40dcce7604b..56f96678934bf 100644 > --- a/kernel/dma/pool.c > +++ b/kernel/dma/pool.c > @@ -184,6 +184,15 @@ static __init struct gen_pool *__dma_atomic_pool_init(size_t pool_size, > return pool; > } > > +static unsigned long calculate_pool_size(unsigned long zone_pages) > +{ > + unsigned long nr_pages = min_t(unsigned long, > + zone_pages / (SZ_1G / SZ_128K), > + MAX_ORDER_NR_PAGES);
Nit: this is arguably less readable, and objectively one line longer, than the original two statements.
Other that those nits though,
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
> + > + return max_t(unsigned long, nr_pages << PAGE_SHIFT, SZ_128K); > +} > + > static int __init dma_atomic_pool_init(void) > { > int ret = 0; > @@ -192,11 +201,9 @@ static int __init dma_atomic_pool_init(void) > * If coherent_pool was not used on the command line, default the pool > * sizes to 128KB per 1GB of memory, min 128KB, max MAX_ORDER-1. > */ > - if (!atomic_pool_size) { > - unsigned long pages = totalram_pages() / (SZ_1G / SZ_128K); > - pages = min_t(unsigned long, pages, MAX_ORDER_NR_PAGES); > - atomic_pool_size = max_t(size_t, pages << PAGE_SHIFT, SZ_128K); > - } > + if (!atomic_pool_size) > + atomic_pool_size = calculate_pool_size(totalram_pages()); > + > INIT_WORK(&atomic_pool_work, atomic_pool_work_fn); > > atomic_pool_kernel = __dma_atomic_pool_init(atomic_pool_size,
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