From: Yong Wu <yong.wu@mediatek.com>
To: Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>,
Krzysztof Kozlowski <krzk@kernel.org>,
Tomasz Figa <tfiga@google.com>,
<linux-mediatek@lists.infradead.org>,
<srv_heupstream@mediatek.com>, <linux-kernel@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<iommu@lists.linux-foundation.org>, <yong.wu@mediatek.com>,
<youlin.pei@mediatek.com>,
Nicolas Boichat <drinkcat@chromium.org>, <anan.sun@mediatek.com>,
<chao.hao@mediatek.com>
Subject: [PATCH v2] iommu: Improve the performance for direct_mapping
Date: Mon, 7 Dec 2020 17:35:53 +0800 [thread overview]
Message-ID: <20201207093553.8635-1-yong.wu@mediatek.com> (raw)
Currently direct_mapping always use the smallest pgsize which is SZ_4K
normally to mapping. This is unnecessary. we could gather the size, and
call iommu_map then, iommu_map could decide how to map better with the
just right pgsize.
From the original comment, we should take care overlap, otherwise,
iommu_map may return -EEXIST. In this overlap case, we should map the
previous region before overlap firstly. then map the left part.
Each a iommu device will call this direct_mapping when its iommu
initialize, This patch is effective to improve the boot/initialization
time especially while it only needs level 1 mapping.
Signed-off-by: Anan Sun <anan.sun@mediatek.com>
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
---
change notes:
v2: Refine the code flow.
v1: https://lore.kernel.org/linux-iommu/20201120090628.6566-1-yong.wu@mediatek.com/
base on v5.10-rc1.
---
drivers/iommu/iommu.c | 22 +++++++++++++++++-----
1 file changed, 17 insertions(+), 5 deletions(-)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 8c470f451a32..1a91decb95fa 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -737,6 +737,7 @@ static int iommu_create_device_direct_mappings(struct iommu_group *group,
/* We need to consider overlapping regions for different devices */
list_for_each_entry(entry, &mappings, list) {
dma_addr_t start, end, addr;
+ size_t map_size = 0;
if (domain->ops->apply_resv_region)
domain->ops->apply_resv_region(dev, domain, entry);
@@ -748,16 +749,27 @@ static int iommu_create_device_direct_mappings(struct iommu_group *group,
entry->type != IOMMU_RESV_DIRECT_RELAXABLE)
continue;
- for (addr = start; addr < end; addr += pg_size) {
+ for (addr = start; addr <= end; addr += pg_size) {
phys_addr_t phys_addr;
+ if (addr == end)
+ goto map_end;
+
phys_addr = iommu_iova_to_phys(domain, addr);
- if (phys_addr)
+ if (!phys_addr) {
+ map_size += pg_size;
continue;
+ }
- ret = iommu_map(domain, addr, addr, pg_size, entry->prot);
- if (ret)
- goto out;
+map_end:
+ if (map_size) {
+ ret = iommu_map(domain, addr - map_size,
+ addr - map_size, map_size,
+ entry->prot);
+ if (ret)
+ goto out;
+ map_size = 0;
+ }
}
}
--
2.18.0
next reply other threads:[~2020-12-07 9:37 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-07 9:35 Yong Wu [this message]
2020-12-07 11:05 ` [PATCH v2] iommu: Improve the performance for direct_mapping Will Deacon
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