From: Robin Murphy robin.murphy@arm.com
mainline inclusion from mainline-v6.6-rc4 commit 233045378dbbc0a7346127d19a54d4f91e0bd855 category: bugfix bugzilla: bugzilla: https://gitee.com/openeuler/kernel/issues/I8PJ8L
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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Automatically scaling the depot up to suit the peak capacity of a workload is all well and good, but it would be nice to have a way to scale it back down again if the workload changes. To that end, add backround reclaim that will gradually free surplus magazines if the depot size remains above a reasonable threshold for long enough.
Reviewed-by: Jerry Snitselaar jsnitsel@redhat.com Signed-off-by: Robin Murphy robin.murphy@arm.com Link: https://lore.kernel.org/r/03170665c56d89c6ce6081246b47f68d4e483308.169453558... Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Zhang Zekun zhangzekun11@huawei.com --- drivers/iommu/iova.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+)
diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c index dd2309e9a6c5..d30e453d0fb4 100644 --- a/drivers/iommu/iova.c +++ b/drivers/iommu/iova.c @@ -11,6 +11,7 @@ #include <linux/smp.h> #include <linux/bitops.h> #include <linux/cpu.h> +#include <linux/workqueue.h>
/* The anchor node sits above the top of the usable address space */ #define IOVA_ANCHOR ~0UL @@ -627,6 +628,8 @@ EXPORT_SYMBOL_GPL(reserve_iova); */ #define IOVA_MAG_SIZE 127
+#define IOVA_DEPOT_DELAY msecs_to_jiffies(100) + struct iova_magazine { union { unsigned long size; @@ -644,8 +647,11 @@ struct iova_cpu_rcache {
struct iova_rcache { spinlock_t lock; + unsigned int depot_size; struct iova_magazine *depot; struct iova_cpu_rcache __percpu *cpu_rcaches; + struct iova_domain *iovad; + struct delayed_work work; };
static struct iova_magazine *iova_magazine_alloc(gfp_t flags) @@ -726,6 +732,7 @@ static struct iova_magazine *iova_depot_pop(struct iova_rcache *rcache)
rcache->depot = mag->next; mag->size = IOVA_MAG_SIZE; + rcache->depot_size--; return mag; }
@@ -733,6 +740,25 @@ static void iova_depot_push(struct iova_rcache *rcache, struct iova_magazine *ma { mag->next = rcache->depot; rcache->depot = mag; + rcache->depot_size++; +} + +static void iova_depot_work_func(struct work_struct *work) +{ + struct iova_rcache *rcache = container_of(work, typeof(*rcache), work.work); + struct iova_magazine *mag = NULL; + unsigned long flags; + + spin_lock_irqsave(&rcache->lock, flags); + if (rcache->depot_size > num_online_cpus()) + mag = iova_depot_pop(rcache); + spin_unlock_irqrestore(&rcache->lock, flags); + + if (mag) { + iova_magazine_free_pfns(mag, rcache->iovad); + iova_magazine_free(mag); + schedule_delayed_work(&rcache->work, IOVA_DEPOT_DELAY); + } }
int iova_domain_init_rcaches(struct iova_domain *iovad) @@ -752,6 +778,8 @@ int iova_domain_init_rcaches(struct iova_domain *iovad)
rcache = &iovad->rcaches[i]; spin_lock_init(&rcache->lock); + rcache->iovad = iovad; + INIT_DELAYED_WORK(&rcache->work, iova_depot_work_func); rcache->cpu_rcaches = __alloc_percpu(sizeof(*cpu_rcache), cache_line_size()); if (!rcache->cpu_rcaches) { @@ -812,6 +840,7 @@ static bool __iova_rcache_insert(struct iova_domain *iovad, spin_lock(&rcache->lock); iova_depot_push(rcache, cpu_rcache->loaded); spin_unlock(&rcache->lock); + schedule_delayed_work(&rcache->work, IOVA_DEPOT_DELAY);
cpu_rcache->loaded = new_mag; can_insert = true; @@ -912,6 +941,7 @@ static void free_iova_rcaches(struct iova_domain *iovad) iova_magazine_free(cpu_rcache->prev); } free_percpu(rcache->cpu_rcaches); + cancel_delayed_work_sync(&rcache->work); while (rcache->depot) iova_magazine_free(iova_depot_pop(rcache)); }