From: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
To: <linux-arm-kernel@lists.infradead.org>,
<kvmarm@lists.cs.columbia.edu>, <linux-kernel@vger.kernel.org>
Cc: jean-philippe@linaro.org, julien@xen.org, maz@kernel.org,
linuxarm@huawei.com, catalin.marinas@arm.com, will@kernel.org
Subject: [PATCH v4 02/16] arm64/mm: Move active_asids and reserved_asids to asid_info
Date: Wed, 14 Apr 2021 12:22:58 +0100 [thread overview]
Message-ID: <20210414112312.13704-3-shameerali.kolothum.thodi@huawei.com> (raw)
In-Reply-To: <20210414112312.13704-1-shameerali.kolothum.thodi@huawei.com>
From: Julien Grall <julien.grall@arm.com>
The variables active_asids and reserved_asids hold information for a
given ASID allocator. So move them to the structure asid_info.
At the same time, introduce wrappers to access the active and reserved
ASIDs to make the code clearer.
Signed-off-by: Julien Grall <julien.grall@arm.com>
Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
---
v3-->v4
keep the this_cpu_ptr in fastpath. See c4885bbb3afe("arm64/mm: save
memory access in check_and_switch_context() fast switch path")
---
arch/arm64/mm/context.c | 32 ++++++++++++++++++++------------
1 file changed, 20 insertions(+), 12 deletions(-)
diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c
index 783f8bdb91ee..42e011094571 100644
--- a/arch/arm64/mm/context.c
+++ b/arch/arm64/mm/context.c
@@ -25,8 +25,13 @@ static struct asid_info
atomic64_t generation;
unsigned long *map;
unsigned int map_idx;
+ atomic64_t __percpu *active;
+ u64 __percpu *reserved;
} asid_info;
+#define active_asid(info, cpu) (*per_cpu_ptr((info)->active, cpu))
+#define reserved_asid(info, cpu) (*per_cpu_ptr((info)->reserved, cpu))
+
static DEFINE_PER_CPU(atomic64_t, active_asids);
static DEFINE_PER_CPU(u64, reserved_asids);
static cpumask_t tlb_flush_pending;
@@ -114,7 +119,7 @@ static void flush_context(struct asid_info *info)
set_reserved_asid_bits(info);
for_each_possible_cpu(i) {
- asid = atomic64_xchg_relaxed(&per_cpu(active_asids, i), 0);
+ asid = atomic64_xchg_relaxed(&active_asid(info, i), 0);
/*
* If this CPU has already been through a
* rollover, but hasn't run another task in
@@ -123,9 +128,9 @@ static void flush_context(struct asid_info *info)
* the process it is still running.
*/
if (asid == 0)
- asid = per_cpu(reserved_asids, i);
+ asid = reserved_asid(info, i);
__set_bit(asid2idx(asid), info->map);
- per_cpu(reserved_asids, i) = asid;
+ reserved_asid(info, i) = asid;
}
/*
@@ -135,7 +140,8 @@ static void flush_context(struct asid_info *info)
cpumask_setall(&tlb_flush_pending);
}
-static bool check_update_reserved_asid(u64 asid, u64 newasid)
+static bool check_update_reserved_asid(struct asid_info *info, u64 asid,
+ u64 newasid)
{
int cpu;
bool hit = false;
@@ -150,9 +156,9 @@ static bool check_update_reserved_asid(u64 asid, u64 newasid)
* generation.
*/
for_each_possible_cpu(cpu) {
- if (per_cpu(reserved_asids, cpu) == asid) {
+ if (reserved_asid(info, cpu) == asid) {
hit = true;
- per_cpu(reserved_asids, cpu) = newasid;
+ reserved_asid(info, cpu) = newasid;
}
}
@@ -171,7 +177,7 @@ static u64 new_context(struct asid_info *info, struct mm_struct *mm)
* If our current ASID was active during a rollover, we
* can continue to use it and this was just a false alarm.
*/
- if (check_update_reserved_asid(asid, newasid))
+ if (check_update_reserved_asid(info, asid, newasid))
return newasid;
/*
@@ -229,8 +235,8 @@ void check_and_switch_context(struct mm_struct *mm)
/*
* The memory ordering here is subtle.
- * If our active_asids is non-zero and the ASID matches the current
- * generation, then we update the active_asids entry with a relaxed
+ * If our active_asid is non-zero and the ASID matches the current
+ * generation, then we update the active_asid entry with a relaxed
* cmpxchg. Racing with a concurrent rollover means that either:
*
* - We get a zero back from the cmpxchg and end up waiting on the
@@ -241,9 +247,9 @@ void check_and_switch_context(struct mm_struct *mm)
* relaxed xchg in flush_context will treat us as reserved
* because atomic RmWs are totally ordered for a given location.
*/
- old_active_asid = atomic64_read(this_cpu_ptr(&active_asids));
+ old_active_asid = atomic64_read(this_cpu_ptr(info->active));
if (old_active_asid && asid_gen_match(asid, info) &&
- atomic64_cmpxchg_relaxed(this_cpu_ptr(&active_asids),
+ atomic64_cmpxchg_relaxed(this_cpu_ptr(info->active),
old_active_asid, asid))
goto switch_mm_fastpath;
@@ -259,7 +265,7 @@ void check_and_switch_context(struct mm_struct *mm)
if (cpumask_test_and_clear_cpu(cpu, &tlb_flush_pending))
local_flush_tlb_all();
- atomic64_set(this_cpu_ptr(&active_asids), asid);
+ atomic64_set(&active_asid(info, cpu), asid);
raw_spin_unlock_irqrestore(&cpu_asid_lock, flags);
switch_mm_fastpath:
@@ -416,6 +422,8 @@ static int asids_init(void)
NUM_USER_ASIDS);
info->map_idx = 1;
+ info->active = &active_asids;
+ info->reserved = &reserved_asids;
pinned_asid_map = kcalloc(BITS_TO_LONGS(NUM_USER_ASIDS),
sizeof(*pinned_asid_map), GFP_KERNEL);
--
2.17.1
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next prev parent reply other threads:[~2021-04-14 11:24 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-14 11:22 [PATCH v4 00/16] kvm/arm: Align the VMID allocation with the arm64 ASID one Shameer Kolothum
2021-04-14 11:22 ` [PATCH v4 01/16] arm64/mm: Introduce asid_info structure and move asid_generation/asid_map to it Shameer Kolothum
2021-04-14 11:22 ` Shameer Kolothum [this message]
2021-04-14 11:22 ` [PATCH v4 03/16] arm64/mm: Move bits to asid_info Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 04/16] arm64/mm: Move the variable lock and tlb_flush_pending " Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 05/16] arm64/mm: Remove dependency on MM in new_context Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 06/16] arm64/mm: Introduce NUM_CTXT_ASIDS Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 07/16] arm64/mm: Move Pinned ASID related variables to asid_info Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 08/16] arm64/mm: Split asid_inits in 2 parts Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 09/16] arm64/mm: Split the function check_and_switch_context in 3 parts Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 10/16] arm64/mm: Split the arm64_mm_context_get/put Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 11/16] arm64/mm: Introduce a callback to flush the local context Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 12/16] arm64/mm: Introduce a callback to set reserved bits Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 13/16] arm64: Move the ASID allocator code in a separate file Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 14/16] arm64/lib: Add an helper to free memory allocated by the ASID allocator Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 15/16] arch/arm64: Introduce a capability to tell whether 16-bit VMID is available Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 16/16] kvm/arm: Align the VMID allocation with the arm64 ASID one Shameer Kolothum
2021-04-22 16:08 ` [PATCH v4 00/16] " Will Deacon
2021-04-23 8:31 ` Shameerali Kolothum Thodi
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