mirror of
https://github.com/checkpoint-restore/criu.git
synced 2026-07-22 09:39:13 +00:00
2acc741a3a
We switch generic-object-id concept with sys_kcmp approach, which implies changes of image format a bit (and since it's early time for project overall, we're allowed to). In short -- previously every file descriptor had an ID generated by a kernel and exported via procfs. If the appropriate file descriptors were the same objects in kernel memory -- the IDs did match up to bit. It allows us to figure out which files were actually the identical ones and should be restored in a special way. Once sys_kcmp system call was merged into the kernel, we've got a new opprotunity -- to use this syscall instead. The syscall basically compares kernel objects and returns ordered results suitable for objects sorting in a userspace. For us it means -- we treat every file descriptor as a combination of 'genid' and 'subid'. While 'genid' serves for fast comparison between fds, the 'subid' is kind of a second key, which guarantees uniqueness of genid+subid tuple over all file descritors found in a process (or group of processes). To be able to find and dump file descriptors in a single pass we collect every fd into a global rbtree, where (!) each node might become a root for a subtree as well. The main tree carries only non-equal genid. If we find genid which is already in tree, we need to make sure that it's either indeed a duplicate or not. For this we use sys_kcmp syscall and if we find that file descriptors are different -- we simply put new fd into a subtree. Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Acked-by: Pavel Emelyanov <xemul@parallels.com>
94 lines
2.6 KiB
C
94 lines
2.6 KiB
C
/*
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* RBtree implementation adopted from the Linux kernel sources.
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*/
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#ifndef RBTREE_H__
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#define RBTREE_H__
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#include <stddef.h>
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#include "compiler.h"
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#include "types.h"
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#define RB_RED 0
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#define RB_BLACK 1
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#define RB_MASK 3
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struct rb_node {
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unsigned long rb_parent_color; /* Keeps both parent anc color */
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struct rb_node *rb_right;
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struct rb_node *rb_left;
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} __aligned(sizeof(long));
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struct rb_root {
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struct rb_node *rb_node;
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};
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#define rb_parent(r) ((struct rb_node *)((r)->rb_parent_color & ~RB_MASK))
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#define rb_color(r) ((r)->rb_parent_color & RB_BLACK)
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#define rb_is_red(r) (!rb_color(r))
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#define rb_is_black(r) (rb_color(r))
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#define rb_set_red(r) do { (r)->rb_parent_color &= ~RB_BLACK; } while (0)
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#define rb_set_black(r) do { (r)->rb_parent_color |= RB_BLACK; } while (0)
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static void rb_set_parent(struct rb_node *rb, struct rb_node *p)
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{
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rb->rb_parent_color = (rb->rb_parent_color & RB_MASK) | (unsigned long)p;
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}
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static void rb_set_color(struct rb_node *rb, int color)
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{
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rb->rb_parent_color = (rb->rb_parent_color & ~RB_BLACK) | color;
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}
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#define RB_ROOT (struct rb_root){ NULL, }
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#define rb_entry(ptr, type, member) container_of(ptr, type, member)
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#define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL)
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#define RB_EMPTY_NODE(node) (rb_parent(node) == node)
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#define RB_CLEAR_NODE(node) (rb_set_parent(node, node))
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static void rb_init_node(struct rb_node *node)
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{
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*node = (struct rb_node){ };
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RB_CLEAR_NODE(node);
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}
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static void rb_attach_node(struct rb_root *root, struct rb_node *node)
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{
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root->rb_node = node;
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}
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extern void rb_insert_color(struct rb_node *node, struct rb_root *root);
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extern void rb_erase(struct rb_node *node, struct rb_root *root);
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/* Find logical next and previous nodes in a tree */
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extern struct rb_node *rb_first(const struct rb_root *root);
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extern struct rb_node *rb_last(const struct rb_root *root);
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extern struct rb_node *rb_next(const struct rb_node *node);
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extern struct rb_node *rb_prev(const struct rb_node *node);
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/* Fast replacement of a single node without remove/rebalance/add/rebalance */
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extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
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struct rb_root *root);
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static void rb_link_node(struct rb_node *node, struct rb_node *parent,
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struct rb_node **rb_link)
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{
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node->rb_parent_color = (unsigned long)parent;
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node->rb_left = node->rb_right = NULL;
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*rb_link = node;
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}
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static void rb_link_and_balance(struct rb_root *root,
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struct rb_node *node,
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struct rb_node *parent,
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struct rb_node **rb_link)
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{
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rb_link_node(node, parent, rb_link);
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rb_insert_color(node, root);
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}
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#endif /* RBTREE_H__ */
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