Blame SOURCES/libvirt-qemu-domain-Simplify-non-VFIO-memLockLimit-calculation-for-PPC64.patch

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From 18f38f4aee3a3472f5e50786ee221d8d397bc6a8 Mon Sep 17 00:00:00 2001
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Message-Id: <18f38f4aee3a3472f5e50786ee221d8d397bc6a8@dist-git>
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From: Daniel Henrique Barboza <danielhb413@gmail.com>
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Date: Fri, 3 May 2019 13:54:50 +0200
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Subject: [PATCH] qemu: domain: Simplify non-VFIO memLockLimit calculation for
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 PPC64
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@passthroughLimit is being calculated even if @usesVFIO is false. After
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that, an if-else conditional is used to check if we're going to sum it
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up with @baseLimit.
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This patch initializes @passthroughLimit to zero and always returns
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@memKB = @baseLimit + @passthroughLimit. The conditional is then used to
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calculate @passthroughLimit if @usesVFIO == true. This results in some
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cycles being spared for the @usesVFIO == false scenario, but the real
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motivation is to make the code simpler to add an alternative formula to
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calculate @passthroughLimit for NVLink2.
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Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
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Reviewed-by: Erik Skultety <eskultet@redhat.com>
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(cherry picked from commit cf7c5212876b2403de5b0fafedec33af4439526e)
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https: //bugzilla.redhat.com/show_bug.cgi?id=1505998
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Signed-off-by: Erik Skultety <eskultet@redhat.com>
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Message-Id: <a6380e14dfb1c8cb463f5e3eb25bda78dc9d7dd8.1556884442.git.eskultet@redhat.com>
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Reviewed-by: Andrea Bolognani <abologna@redhat.com>
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---
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 src/qemu/qemu_domain.c | 13 +++++--------
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 1 file changed, 5 insertions(+), 8 deletions(-)
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diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
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index cc2a896a07..d936090d87 100644
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--- a/src/qemu/qemu_domain.c
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+++ b/src/qemu/qemu_domain.c
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@@ -9840,7 +9840,7 @@ qemuDomainGetMemLockLimitBytes(virDomainDefPtr def)
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         unsigned long long maxMemory;
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         unsigned long long memory;
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         unsigned long long baseLimit;
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-        unsigned long long passthroughLimit;
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+        unsigned long long passthroughLimit = 0;
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         size_t nPCIHostBridges = 0;
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         bool usesVFIO = false;
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@@ -9906,15 +9906,12 @@ qemuDomainGetMemLockLimitBytes(virDomainDefPtr def)
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          * kiB pages, less still if the guest is mapped with hugepages (unlike
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          * the default 32-bit DMA window, DDW windows can use large IOMMU
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          * pages). 8 MiB is for second and further level overheads, like (b) */
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-        passthroughLimit = MAX(2 * 1024 * 1024 * nPCIHostBridges,
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-                               memory +
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-                               memory / 512 * nPCIHostBridges + 8192);
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-
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         if (usesVFIO)
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-            memKB = baseLimit + passthroughLimit;
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-        else
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-            memKB = baseLimit;
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+            passthroughLimit = MAX(2 * 1024 * 1024 * nPCIHostBridges,
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+                                   memory +
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+                                   memory / 512 * nPCIHostBridges + 8192);
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+        memKB = baseLimit + passthroughLimit;
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         goto done;
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     }
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-- 
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2.21.0
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