search for: __radix_tree_preload

...loop forever __alloc_pages_may_oom() uses mutex_trylock(&oom_lock). I think the second __alloc_pages_may_oom() will not continue since the first one is in progress. > > By the way, is xb_set_page() safe? > Sleeping in the kernel with preemption disabled is a bug, isn't it? > __radix_tree_preload() returns 0 with preemption disabled upon success. > xb_preload() disables preemption if __radix_tree_preload() fails. > Then, kmalloc() is called with preemption disabled, isn't it? > But xb_set_page() calls xb_preload(GFP_KERNEL) which might sleep with > preemption disabled. Yes,...

...id function, since the original implementation reurns nothing than a 0. - remove the comment above "#define XB_INDEX_BITS", because it causes confusion based on the feedbacks from the previous discussion; - xb_preload: with the original implementation, the CPU that successfully do __radix_tree_preload() may get into sleep by kmalloc(), which has a risk of getting the caller of xb_preload() scheduled to another CPU after waken up, and the new CPU may not have radix_tree_node pre-allocated there, this will be a problem when inserting a node to the tree later. This patch moves __radix_tree_...

On Sat, Sep 30, 2017 at 12:05:52PM +0800, Wei Wang wrote: > +static inline void xb_set_page(struct virtio_balloon *vb, > + struct page *page, > + unsigned long *pfn_min, > + unsigned long *pfn_max) > +{ > + unsigned long pfn = page_to_pfn(page); > + > + *pfn_min = min(pfn, *pfn_min); > + *pfn_max = max(pfn, *pfn_max); > +

On Sat, Sep 30, 2017 at 12:05:52PM +0800, Wei Wang wrote: > +static inline void xb_set_page(struct virtio_balloon *vb, > + struct page *page, > + unsigned long *pfn_min, > + unsigned long *pfn_max) > +{ > + unsigned long pfn = page_to_pfn(page); > + > + *pfn_min = min(pfn, *pfn_min); > + *pfn_max = max(pfn, *pfn_max); > +

...balloon() code path, and we can add one more parameter to leak_balloon to control that: leak_balloon(struct virtio_balloon *vb, size_t num, bool oom) >>> By the way, is xb_set_page() safe? >>> Sleeping in the kernel with preemption disabled is a bug, isn't it? >>> __radix_tree_preload() returns 0 with preemption disabled upon success. >>> xb_preload() disables preemption if __radix_tree_preload() fails. >>> Then, kmalloc() is called with preemption disabled, isn't it? >>> But xb_set_page() calls xb_preload(GFP_KERNEL) which might sleep with >&gt...

I'm commenting without understanding the logic. Wei Wang wrote: > + > +bool xb_preload(gfp_t gfp); > + Want __must_check annotation, for __radix_tree_preload() is marked with __must_check annotation. By error failing to check result of xb_preload() will lead to preemption kept disabled unexpectedly. > +int xb_set_bit(struct xb *xb, unsigned long bit) > +{ > + int err; > + unsigned long index = bit / IDA_BITMAP_BITS; > + struct radix_tr...

I'm commenting without understanding the logic. Wei Wang wrote: > + > +bool xb_preload(gfp_t gfp); > + Want __must_check annotation, for __radix_tree_preload() is marked with __must_check annotation. By error failing to check result of xb_preload() will lead to preemption kept disabled unexpectedly. > +int xb_set_bit(struct xb *xb, unsigned long bit) > +{ > + int err; > + unsigned long index = bit / IDA_BITMAP_BITS; > + struct radix_tr...

...*/ > +#define XB_INDEX_BITS (BITS_PER_LONG - ilog2(IDA_BITMAP_BITS)) > +#define XB_MAX_PATH (DIV_ROUND_UP(XB_INDEX_BITS, \ > + RADIX_TREE_MAP_SHIFT)) > +#define XB_PRELOAD_SIZE (XB_MAX_PATH * 2 - 1) > + > > ... > > +void xb_preload(gfp_t gfp) > +{ > + __radix_tree_preload(gfp, XB_PRELOAD_SIZE); > + if (!this_cpu_read(ida_bitmap)) { > + struct ida_bitmap *bitmap = kmalloc(sizeof(*bitmap), gfp); > + > + if (!bitmap) > + return; > + bitmap = this_cpu_cmpxchg(ida_bitmap, NULL, bitmap); > + kfree(bitmap); > + } > +} > +EXPORT_SYMBOL(xb...

...*/ > +#define XB_INDEX_BITS (BITS_PER_LONG - ilog2(IDA_BITMAP_BITS)) > +#define XB_MAX_PATH (DIV_ROUND_UP(XB_INDEX_BITS, \ > + RADIX_TREE_MAP_SHIFT)) > +#define XB_PRELOAD_SIZE (XB_MAX_PATH * 2 - 1) > + > > ... > > +void xb_preload(gfp_t gfp) > +{ > + __radix_tree_preload(gfp, XB_PRELOAD_SIZE); > + if (!this_cpu_read(ida_bitmap)) { > + struct ida_bitmap *bitmap = kmalloc(sizeof(*bitmap), gfp); > + > + if (!bitmap) > + return; > + bitmap = this_cpu_cmpxchg(ida_bitmap, NULL, bitmap); > + kfree(bitmap); > + } > +} > +EXPORT_SYMBOL(xb...

...are an improvement, but without any argumentation from you I don't know why you think they're an improvement. > diff --git a/lib/radix-tree.c b/lib/radix-tree.c > index 898e879..ee72e2c 100644 > --- a/lib/radix-tree.c > +++ b/lib/radix-tree.c > @@ -496,6 +496,7 @@ static int __radix_tree_preload(gfp_t gfp_mask, unsigned nr) > out: > return ret; > } > +EXPORT_SYMBOL(__radix_tree_preload); > > /* > * Load up this CPU's radix_tree_node buffer with sufficient objects to You exported this to modules for some reason. Why? > @@ -2003,6 +2018,7 @@ static boo...

...are an improvement, but without any argumentation from you I don't know why you think they're an improvement. > diff --git a/lib/radix-tree.c b/lib/radix-tree.c > index 898e879..ee72e2c 100644 > --- a/lib/radix-tree.c > +++ b/lib/radix-tree.c > @@ -496,6 +496,7 @@ static int __radix_tree_preload(gfp_t gfp_mask, unsigned nr) > out: > return ret; > } > +EXPORT_SYMBOL(__radix_tree_preload); > > /* > * Load up this CPU's radix_tree_node buffer with sufficient objects to You exported this to modules for some reason. Why? > @@ -2003,6 +2018,7 @@ static boo...

...at microsoft.com> Cc: Andrew Morton <akpm at linux-foundation.org> Cc: Michal Hocko <mhocko at kernel.org> Cc: Michael S. Tsirkin <mst at redhat.com> Cc: Tetsuo Handa <penguin-kernel at I-love.SAKURA.ne.jp> v16->v17 ChangeLog: 1) xb_preload: allocate ida bitmap before __radix_tree_preload() to avoid kmalloc with preemption disabled. Also change this function to return with preemption not disabled on error. 2) xb_preload_and_set_bit: a wrapper of xb_preload and xb_set_bit, for the convenience of usage. v15->v16 ChangeLog: 1) coding style - separate small functions for bit set/cle...

..., + struct radix_tree_node *node, void __rcu **slot) { void *old = rcu_dereference_raw(*slot); int exceptional = radix_tree_exceptional_entry(old) ? -1 : 0; @@ -2137,6 +2148,130 @@ int ida_pre_get(struct ida *ida, gfp_t gfp) } EXPORT_SYMBOL(ida_pre_get); +void xb_preload(gfp_t gfp) +{ + __radix_tree_preload(gfp, XB_PRELOAD_SIZE); + if (!this_cpu_read(ida_bitmap)) { + struct ida_bitmap *bitmap = kmalloc(sizeof(*bitmap), gfp); + + if (!bitmap) + return; + bitmap = this_cpu_cmpxchg(ida_bitmap, NULL, bitmap); + kfree(bitmap); + } +} +EXPORT_SYMBOL(xb_preload); + +int xb_set_bit(struct xb *xb, unsign...

...oot *root, +bool __radix_tree_delete(struct radix_tree_root *root, struct radix_tree_node *node, void __rcu **slot) { void *old = rcu_dereference_raw(*slot); @@ -2135,6 +2142,20 @@ int ida_pre_get(struct ida *ida, gfp_t gfp) } EXPORT_SYMBOL(ida_pre_get); +void xb_preload(gfp_t gfp) +{ + __radix_tree_preload(gfp, XB_PRELOAD_SIZE); + if (!this_cpu_read(ida_bitmap)) { + struct ida_bitmap *bitmap = kmalloc(sizeof(*bitmap), gfp); + + if (!bitmap) + return; + bitmap = this_cpu_cmpxchg(ida_bitmap, NULL, bitmap); + kfree(bitmap); + } +} +EXPORT_SYMBOL(xb_preload); + void __rcu **idr_get_free_cmn(struct...

This patch series enhances the existing virtio-balloon with the following new features: 1) fast ballooning: transfer ballooned pages between the guest and host in chunks using sgs, instead of one array each time; and 2) free page block reporting: a new virtqueue to report guest free pages to the host. The second feature can be used to accelerate live migration of VMs. Here are some details: Live

This patch series enhances the existing virtio-balloon with the following new features: 1) fast ballooning: transfer ballooned pages between the guest and host in chunks using sgs, instead of one array each time; and 2) free page block reporting: a new virtqueue to report guest free pages to the host. The second feature can be used to accelerate live migration of VMs. Here are some details: Live

...oot *root, +bool __radix_tree_delete(struct radix_tree_root *root, struct radix_tree_node *node, void __rcu **slot) { void *old = rcu_dereference_raw(*slot); @@ -2135,6 +2145,20 @@ int ida_pre_get(struct ida *ida, gfp_t gfp) } EXPORT_SYMBOL(ida_pre_get); +void xb_preload(gfp_t gfp) +{ + __radix_tree_preload(gfp, XB_PRELOAD_SIZE); + if (!this_cpu_read(ida_bitmap)) { + struct ida_bitmap *bitmap = kmalloc(sizeof(*bitmap), gfp); + + if (!bitmap) + return; + bitmap = this_cpu_cmpxchg(ida_bitmap, NULL, bitmap); + kfree(bitmap); + } +} +EXPORT_SYMBOL(xb_preload); + void __rcu **idr_get_free_cmn(struct...

This patch series enhances the existing virtio-balloon with the following new features: 1) fast ballooning: transfer ballooned pages between the guest and host in chunks using sgs, instead of one array each time; and 2) free page block reporting: a new virtqueue to report guest free pages to the host. The second feature can be used to accelerate live migration of VMs. Here are some details: Live

This patch series enhances the existing virtio-balloon with the following new features: 1) fast ballooning: transfer ballooned pages between the guest and host in chunks using sgs, instead of one array each time; and 2) free page block reporting: a new virtqueue to report guest free pages to the host. The second feature can be used to accelerate live migration of VMs. Here are some details: Live

This patch series enhances the existing virtio-balloon with the following new features: 1) fast ballooning: transfer ballooned pages between the guest and host in chunks using sgs, instead of one array each time; and 2) free page block reporting: a new virtqueue to report guest free pages to the host. The second feature can be used to accelerate live migration of VMs. Here are some details: Live