search for: idr_free

...turn 0; /* Already set */ > > > > > > Why already set? I guess something is there, but is it guaranteed that > > > there is a bitmap with the "bit" set? > > > > Yes. For radix trees tagged with IDR_RT_MARKER, newly created slots > > have the IDR_FREE tag set. We only clear the IDR_FREE tag once the > > bitmap is full. So if we try to find a free slot and the tag is clear, > > we know the bitmap is full. > > > > OK. But does using IDR_FREE tag have more benefit than cost? > You are doing > > if (bitmap_full...

This patch adds support to find next 1 or 0 bit in a xbmitmap range and clear a range of bits. More possible optimizations to add in the future: 1) xb_set_bit_range: set a range of bits. 2) when searching a bit, if the bit is not found in the slot, move on to the next slot directly. 3) add tags to help searching. Signed-off-by: Wei Wang <wei.w.wang at intel.com> Cc: Matthew Wilcox

This patch adds support to find next 1 or 0 bit in a xbmitmap range and clear a range of bits. More possible optimizations to add in the future: 1) xb_set_bit_range: set a range of bits. 2) when searching a bit, if the bit is not found in the slot, move on to the next slot directly. 3) add tags to help searching. Signed-off-by: Wei Wang <wei.w.wang at intel.com> Cc: Matthew Wilcox

...> > + if (slot == ERR_PTR(-ENOSPC)) > > + return 0; /* Already set */ > > Why already set? I guess something is there, but is it guaranteed that > there is a bitmap with the "bit" set? Yes. For radix trees tagged with IDR_RT_MARKER, newly created slots have the IDR_FREE tag set. We only clear the IDR_FREE tag once the bitmap is full. So if we try to find a free slot and the tag is clear, we know the bitmap is full. > > + bitmap = rcu_dereference_raw(*slot); > > + if (!bitmap) { > > + bitmap = this_cpu_xchg(ida_bitmap, NULL); > > + if (...

OK, here's a rewrite of xbitmap. Compared to the version you sent: - xb_find_set() is the rewrite I sent out yesterday. - xb_find_clear() is a new implementation. I use the IDR_FREE tag to find clear bits. This led to me finding a bug in radix_tree_for_each_tagged(). - xb_zero() is also a new implementation (replacing xb_clear_bit_range). It should also be more efficient in deep trees. - Did not accept your change to xb_set_bit(); I think it's important to leav...

...hg(ida_bitmap, NULL); + if (!bitmap) + return -ENOMEM; + memset(bitmap, 0, sizeof(*bitmap)); + radix_tree_iter_replace(root, &iter, slot, bitmap); + } + + __set_bit(bit, bitmap->bitmap); + if (bitmap_full(bitmap->bitmap, IDA_BITMAP_BITS)) + radix_tree_iter_tag_clear(root, &iter, IDR_FREE); + return 0; +} +EXPORT_SYMBOL(xb_set_bit); + +/** + * xb_clear_bit() - Clear a bit in the XBitmap. + * @xb: The XBitmap. + * @bit: Index of the bit to clear. + * + * This function is used to clear a bit in the xbitmap. + */ +void xb_clear_bit(struct xb *xb, unsigned long bit) +{ + unsigned long i...

On 12/22/2017 05:03 AM, Matthew Wilcox wrote: > OK, here's a rewrite of xbitmap. > > Compared to the version you sent: > - xb_find_set() is the rewrite I sent out yesterday. > - xb_find_clear() is a new implementation. I use the IDR_FREE tag to find > clear bits. This led to me finding a bug in radix_tree_for_each_tagged(). > - xb_zero() is also a new implementation (replacing xb_clear_bit_range). > It should also be more efficient in deep trees. > - Did not accept your change to xb_set_bit(); I think it...

On 12/22/2017 05:03 AM, Matthew Wilcox wrote: > OK, here's a rewrite of xbitmap. > > Compared to the version you sent: > - xb_find_set() is the rewrite I sent out yesterday. > - xb_find_clear() is a new implementation. I use the IDR_FREE tag to find > clear bits. This led to me finding a bug in radix_tree_for_each_tagged(). > - xb_zero() is also a new implementation (replacing xb_clear_bit_range). > It should also be more efficient in deep trees. > - Did not accept your change to xb_set_bit(); I think it...

...(XB_MAX_PATH * 2 - 1) + +/* * Per-cpu pool of preloaded nodes */ struct radix_tree_preload { @@ -840,6 +849,8 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, offset, 0, 0); if (!child) return -ENOMEM; + if (is_idr(root)) + all_tag_set(child, IDR_FREE); rcu_assign_pointer(*slot, node_to_entry(child)); if (node) node->count++; @@ -1986,8 +1997,8 @@ void __radix_tree_delete_node(struct radix_tree_root *root, delete_node(root, node, update_node, private); } -static bool __radix_tree_delete(struct radix_tree_root *root, - str...

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

...T)) +#define XB_PRELOAD_SIZE (XB_MAX_PATH * 2 - 1) + /* * Per-cpu pool of preloaded nodes */ @@ -839,6 +844,8 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, offset, 0, 0); if (!child) return -ENOMEM; + if (is_idr(root)) + all_tag_set(child, IDR_FREE); rcu_assign_pointer(*slot, node_to_entry(child)); if (node) node->count++; @@ -1982,7 +1989,7 @@ void __radix_tree_delete_node(struct radix_tree_root *root, delete_node(root, node, update_node); } -static bool __radix_tree_delete(struct radix_tree_root *root, +bool __radix_tre...

...(XB_MAX_PATH * 2 - 1) + +/* * Per-cpu pool of preloaded nodes */ struct radix_tree_preload { @@ -839,6 +847,8 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, offset, 0, 0); if (!child) return -ENOMEM; + if (is_idr(root)) + all_tag_set(child, IDR_FREE); rcu_assign_pointer(*slot, node_to_entry(child)); if (node) node->count++; @@ -1982,7 +1992,7 @@ void __radix_tree_delete_node(struct radix_tree_root *root, delete_node(root, node, update_node); } -static bool __radix_tree_delete(struct radix_tree_root *root, +bool __radix_tre...

...(XB_MAX_PATH * 2 - 1) + +/* * Per-cpu pool of preloaded nodes */ struct radix_tree_preload { @@ -840,6 +853,8 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, offset, 0, 0); if (!child) return -ENOMEM; + if (is_idr(root)) + all_tag_set(child, IDR_FREE); rcu_assign_pointer(*slot, node_to_entry(child)); if (node) node->count++; @@ -1986,8 +2001,8 @@ void __radix_tree_delete_node(struct radix_tree_root *root, delete_node(root, node, update_node, private); } -static bool __radix_tree_delete(struct radix_tree_root *root, - str...

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 by one; and 2) free_page_vq: 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 migration needs to

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 by one; and 2) free_page_vq: 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 migration needs to

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

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