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| author | Feng Tang <feng.tang@intel.com> | 2022-07-03 19:44:50 +0800 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2022-07-06 13:30:14 +0200 |
| commit | b4c9bf178ace26c52c9cac36f265ba95132a221d (patch) | |
| tree | 5fbd436321742a6a5441006f3278587d5c31773f /drivers/iommu/iova.c | |
| parent | 4d26ba671e3deed010311345e4426e6e11eaaf4c (diff) | |
| download | linux-stable-b4c9bf178ace26c52c9cac36f265ba95132a221d.tar.gz linux-stable-b4c9bf178ace26c52c9cac36f265ba95132a221d.tar.bz2 linux-stable-b4c9bf178ace26c52c9cac36f265ba95132a221d.zip | |
iommu/iova: change IOVA_MAG_SIZE to 127 to save memory
kmalloc will round up the request size to power of 2, and current
iova_magazine's size is 1032 (1024+8) bytes, so each instance
allocated will get 2048 bytes from kmalloc, causing around 1KB
waste.
Change IOVA_MAG_SIZE from 128 to 127 to make size of 'iova_magazine'
1024 bytes so that no memory will be wasted.
Signed-off-by: Feng Tang <feng.tang@intel.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20220703114450.15184-1-feng.tang@intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'drivers/iommu/iova.c')
| -rw-r--r-- | drivers/iommu/iova.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c index db77aa675145..e44f565c5319 100644 --- a/drivers/iommu/iova.c +++ b/drivers/iommu/iova.c @@ -614,7 +614,12 @@ EXPORT_SYMBOL_GPL(reserve_iova); * dynamic size tuning described in the paper. */ -#define IOVA_MAG_SIZE 128 +/* + * As kmalloc's buffer size is fixed to power of 2, 127 is chosen to + * assure size of 'iova_magazine' to be 1024 bytes, so that no memory + * will be wasted. + */ +#define IOVA_MAG_SIZE 127 #define MAX_GLOBAL_MAGS 32 /* magazines per bin */ struct iova_magazine { |