diff options
| author | Robin Murphy <robin.murphy@arm.com> | 2026-01-12 15:46:38 +0000 |
|---|---|---|
| committer | Marek Szyprowski <m.szyprowski@samsung.com> | 2026-01-14 11:00:00 +0100 |
| commit | c6ccd098807483762ccd726e1498bac5a71d0005 (patch) | |
| tree | 38064d3e4ec8596bbf438a53e12fdcd904482669 /kernel | |
| parent | 6626734dd2b151753e134730e27d17e64784c345 (diff) | |
dma/pool: Avoid allocating redundant pools
On smaller systems, e.g. embedded arm64, it is common for all memory
to end up in ZONE_DMA32 or even ZONE_DMA. In such cases it is redundant
to allocate a nominal pool for an empty higher zone that just ends up
coming from a lower zone that should already have its own pool anyway.
We already have logic to skip allocating a ZONE_DMA pool when that is
empty, so generalise that to save memory in the case of other zones too.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Vladimir Kondratiev <vladimir.kondratiev@mobileye.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/8ab8d8a620dee0109f33f5cb63d6bfeed35aac37.1768230104.git.robin.murphy@arm.com
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/dma/pool.c | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c index 2645cfb5718b..c5da29ad010c 100644 --- a/kernel/dma/pool.c +++ b/kernel/dma/pool.c @@ -184,6 +184,12 @@ static __init struct gen_pool *__dma_atomic_pool_init(size_t pool_size, return pool; } +#ifdef CONFIG_ZONE_DMA32 +#define has_managed_dma32 has_managed_zone(ZONE_DMA32) +#else +#define has_managed_dma32 false +#endif + static int __init dma_atomic_pool_init(void) { int ret = 0; @@ -199,17 +205,20 @@ static int __init dma_atomic_pool_init(void) } INIT_WORK(&atomic_pool_work, atomic_pool_work_fn); - atomic_pool_kernel = __dma_atomic_pool_init(atomic_pool_size, + /* All memory might be in the DMA zone(s) to begin with */ + if (has_managed_zone(ZONE_NORMAL)) { + atomic_pool_kernel = __dma_atomic_pool_init(atomic_pool_size, GFP_KERNEL); - if (!atomic_pool_kernel) - ret = -ENOMEM; + if (!atomic_pool_kernel) + ret = -ENOMEM; + } if (has_managed_dma()) { atomic_pool_dma = __dma_atomic_pool_init(atomic_pool_size, GFP_KERNEL | GFP_DMA); if (!atomic_pool_dma) ret = -ENOMEM; } - if (IS_ENABLED(CONFIG_ZONE_DMA32)) { + if (has_managed_dma32) { atomic_pool_dma32 = __dma_atomic_pool_init(atomic_pool_size, GFP_KERNEL | GFP_DMA32); if (!atomic_pool_dma32) @@ -228,7 +237,7 @@ static inline struct gen_pool *dma_guess_pool(struct gen_pool *prev, gfp_t gfp) return atomic_pool_dma ?: atomic_pool_dma32 ?: atomic_pool_kernel; if (gfp & GFP_DMA32) return atomic_pool_dma32 ?: atomic_pool_dma ?: atomic_pool_kernel; - return atomic_pool_kernel; + return atomic_pool_kernel ?: atomic_pool_dma32 ?: atomic_pool_dma; } if (prev == atomic_pool_kernel) return atomic_pool_dma32 ? atomic_pool_dma32 : atomic_pool_dma; |