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From: Wei Yang <richard.weiyang@gmail.com>
To: joro@8bytes.org
Cc: dwmw2@infradead.org, iommu@lists.linux-foundation.org,
	linux-kernel@vger.kernel.org,
	Wei Yang <richard.weiyang@gmail.com>
Subject: [PATCH] iommu/vt-d: reduce extra first level entry in iommu->domains
Date: Sat, 21 May 2016 02:41:51 +0000	[thread overview]
Message-ID: <1463798511-4015-1-git-send-email-richard.weiyang@gmail.com> (raw)

In commit <8bf478163e69> ("iommu/vt-d: Split up iommu->domains array"), it
it splits iommu->domains in two levels. Each first level contains 256
entries of second level. In case of the ndomains is exact a multiple of
256, it would have one more extra first level entry for current
implementation.

This patch refines this calculation to reduce the extra first level entry.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
---
 drivers/iommu/intel-iommu.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index e3061d3..2204ca4 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1634,7 +1634,7 @@ static int iommu_init_domains(struct intel_iommu *iommu)
 		return -ENOMEM;
 	}
 
-	size = ((ndomains >> 8) + 1) * sizeof(struct dmar_domain **);
+	size = (ALIGN(ndomains, 256) >> 8) * sizeof(struct dmar_domain **);
 	iommu->domains = kzalloc(size, GFP_KERNEL);
 
 	if (iommu->domains) {
@@ -1699,7 +1699,7 @@ static void disable_dmar_iommu(struct intel_iommu *iommu)
 static void free_dmar_iommu(struct intel_iommu *iommu)
 {
 	if ((iommu->domains) && (iommu->domain_ids)) {
-		int elems = (cap_ndoms(iommu->cap) >> 8) + 1;
+		int elems = ALIGN(cap_ndoms(iommu->cap), 256) >> 8;
 		int i;
 
 		for (i = 0; i < elems; i++)
-- 
1.7.9.5

WARNING: multiple messages have this Message-ID (diff)
From: Wei Yang <richard.weiyang-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org
Cc: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
	dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Wei Yang
	<richard.weiyang-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Subject: [PATCH] iommu/vt-d: reduce extra first level entry in iommu->domains
Date: Sat, 21 May 2016 02:41:51 +0000	[thread overview]
Message-ID: <1463798511-4015-1-git-send-email-richard.weiyang@gmail.com> (raw)

In commit <8bf478163e69> ("iommu/vt-d: Split up iommu->domains array"), it
it splits iommu->domains in two levels. Each first level contains 256
entries of second level. In case of the ndomains is exact a multiple of
256, it would have one more extra first level entry for current
implementation.

This patch refines this calculation to reduce the extra first level entry.

Signed-off-by: Wei Yang <richard.weiyang-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 drivers/iommu/intel-iommu.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index e3061d3..2204ca4 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1634,7 +1634,7 @@ static int iommu_init_domains(struct intel_iommu *iommu)
 		return -ENOMEM;
 	}
 
-	size = ((ndomains >> 8) + 1) * sizeof(struct dmar_domain **);
+	size = (ALIGN(ndomains, 256) >> 8) * sizeof(struct dmar_domain **);
 	iommu->domains = kzalloc(size, GFP_KERNEL);
 
 	if (iommu->domains) {
@@ -1699,7 +1699,7 @@ static void disable_dmar_iommu(struct intel_iommu *iommu)
 static void free_dmar_iommu(struct intel_iommu *iommu)
 {
 	if ((iommu->domains) && (iommu->domain_ids)) {
-		int elems = (cap_ndoms(iommu->cap) >> 8) + 1;
+		int elems = ALIGN(cap_ndoms(iommu->cap), 256) >> 8;
 		int i;
 
 		for (i = 0; i < elems; i++)
-- 
1.7.9.5

             reply	other threads:[~2016-05-21  2:42 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-21  2:41 Wei Yang [this message]
2016-05-21  2:41 ` [PATCH] iommu/vt-d: reduce extra first level entry in iommu->domains Wei Yang
2016-05-24 23:06 ` Wei Yang
2016-05-24 23:06   ` Wei Yang
2016-05-25 10:17   ` Robin Murphy
2016-05-25 21:43     ` Wei Yang
2016-05-25 21:43       ` Wei Yang
2016-05-26 10:11       ` Robin Murphy
2016-05-26 22:34         ` Wei Yang
2016-06-15 11:39   ` Joerg Roedel
2016-06-15 11:39     ` Joerg Roedel
2016-06-16 22:51     ` Wei Yang

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