Commit 3ee06a6d authored Jun 08, 2020 by Geert Uytterhoeven Committed by Christoph Hellwig Jun 09, 2020

dma-pool: fix too large DMA pools on medium memory size systems



On systems with at least 32 MiB, but less than 32 GiB of RAM, the DMA
memory pools are much larger than intended (e.g. 2 MiB instead of 128
KiB on a 256 MiB system).

Fix this by correcting the calculation of the number of GiBs of RAM in
the system.  Invert the order of the min/max operations, to keep on
calculating in pages until the last step, which aids readability.

Fixes: 1d659236 ("dma-pool: scale the default DMA coherent pool size with memory capacity")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

parent abfbb292

kernel/dma/pool.c

+3 −4

Original line number	Diff line number	Diff line
		@@ -175,10 +175,9 @@ static int __init dma_atomic_pool_init(void)
		* sizes to 128KB per 1GB of memory, min 128KB, max MAX_ORDER-1.
		*/
		if (!atomic_pool_size) {
		atomic_pool_size = max(totalram_pages() >> PAGE_SHIFT, 1UL) *
		SZ_128K;
		atomic_pool_size = min_t(size_t, atomic_pool_size,
		1 << (PAGE_SHIFT + MAX_ORDER-1));
		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);
		}
		INIT_WORK(&atomic_pool_work, atomic_pool_work_fn);

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