mirror of
https://github.com/checkpoint-restore/criu.git
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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>
71 lines
1.9 KiB
C
71 lines
1.9 KiB
C
#ifndef CR_COMPILER_H_
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#define CR_COMPILER_H_
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/*
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* Various definitions for success build,
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* picked from various places, mostly from
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* the linux kernel.
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*/
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#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
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#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
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#define __stringify_1(x...) #x
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#define __stringify(x...) __stringify_1(x)
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#define NORETURN __attribute__((__noreturn__))
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#define __packed __attribute__((__packed__))
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#define __used __attribute__((__used__))
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#define __maybe_unused __attribute__((unused))
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#define __always_unused __attribute__((unused))
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#define __section(S) __attribute__ ((__section__(#S)))
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#ifndef __always_inline
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# define __always_inline inline __attribute__((always_inline))
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#endif
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#define likely(x) __builtin_expect(!!(x), 1)
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#define unlikely(x) __builtin_expect(!!(x), 0)
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#ifndef always_inline
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# define always_inline __always_inline
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#endif
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#ifndef noinline
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# define noinline __attribute__((noinline))
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#endif
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#define __aligned(x) __attribute__((aligned(x)))
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#ifndef offsetof
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# define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
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#endif
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#define barrier() asm volatile("" ::: "memory")
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#define container_of(ptr, type, member) ({ \
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const typeof( ((type *)0)->member ) *__mptr = (ptr); \
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(type *)( (char *)__mptr - offsetof(type,member) );})
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#define __round_mask(x, y) ((__typeof__(x))((y) - 1))
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#define round_up(x, y) ((((x) - 1) | __round_mask(x, y)) + 1)
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#define round_down(x, y) ((x) & ~__round_mask(x, y))
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#define DIV_ROUND_UP(n,d) (((n) + (d) - 1) / (d))
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#define ALIGN(x, a) (((x) + (a) - 1) & ~((a) - 1))
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#define min(x, y) ({ \
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typeof(x) _min1 = (x); \
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typeof(y) _min2 = (y); \
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(void) (&_min1 == &_min2); \
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_min1 < _min2 ? _min1 : _min2; })
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#define max(x, y) ({ \
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typeof(x) _max1 = (x); \
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typeof(y) _max2 = (y); \
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(void) (&_max1 == &_max2); \
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_max1 > _max2 ? _max1 : _max2; })
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#define is_log2(v) (((v) & ((v) - 1)) == 0)
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#endif /* CR_COMPILER_H_ */
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