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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 2 of 3] remus: move makeheader from image.py to vm.py
# HG changeset patch
# User Shriram Rajagopalan <rshriram@xxxxxxxxx>
# Date 1307360442 25200
# Node ID dc243b6893366c453834734e0b4b17a3f233daa2
# Parent d681b8ed0d03557f896cbc28d7ec244a2bc75bf2
remus: move makeheader from image.py to vm.py
makeheader is the only function used from image.py. Move it
to vm.py and remove image.py file.
Signed-off-by: Shriram Rajagopalan <rshriram@xxxxxxxxx>
diff -r d681b8ed0d03 -r dc243b689336 tools/python/xen/remus/image.py
--- a/tools/python/xen/remus/image.py Mon Jun 06 04:40:39 2011 -0700
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,227 +0,0 @@
-# VM image file manipulation
-
-import logging, struct
-
-import vm
-
-SIGNATURE = 'LinuxGuestRecord'
-LONGLEN = struct.calcsize('L')
-INTLEN = struct.calcsize('i')
-PAGE_SIZE = 4096
-# ~0L
-P2M_EXT_SIG = 4294967295L
-# frames per page
-FPP = 1024
-LTAB_MASK = 0xf << 28
-BATCH_SIZE = 1024
-IDXLEN = INTLEN + BATCH_SIZE * LONGLEN
-
-logging.basicConfig(level=logging.DEBUG)
-log = logging.getLogger()
-
-class VMParseException(Exception): pass
-
-class VMImage(object):
- def __init__(self, img=None):
- """img may be a path or a file object.
- If compact is True, apply checkpoints to base image instead
- of simply concatenating them.
- """
- self.img = img
-
- self.dom = None
- self.fd = None
- self.header = None
- self.nr_pfns = 0
- # p2m extension header (unparsed)
- self.p2mext = None
-
- if self.img:
- self.open(self.img)
-
- def open(self, img):
- if isinstance(img, str):
- self.fd = file(img, 'rb')
- else:
- self.fd = img
-
- self.readheader()
-
- def readheader(self):
- sig = self.fd.read(len(SIGNATURE))
- if sig != SIGNATURE:
- raise VMParseException("Bad signature in image")
-
- hlen = self.fd.read(INTLEN)
- hlen, = struct.unpack('!i', hlen)
-
- self.header = self.fd.read(hlen)
- self.dom = parseheader(self.header)
-
- def readp2mfl(self):
- "read the P2M frame list"
- pfnlen = self.fd.read(LONGLEN)
- self.nr_pfns, = struct.unpack('L', pfnlen)
- p2m0 = self.fd.read(LONGLEN)
-
- p2mhdr = p2m0
- p2m0, = struct.unpack('L', p2m0)
- if p2m0 == P2M_EXT_SIG:
- elen = self.fd.read(INTLEN)
- elen, = struct.unpack('I', elen)
-
- self.p2mext = self.fd.read(elen)
-
- p2m0 = self.fd.read(LONGLEN)
- p2m0, = struct.unpack('L', p2m0)
- p2mfl = [p2m0]
-
- p2mfle = (self.nr_pfns + FPP - 1)/FPP - 1
- p2ms = self.fd.read(LONGLEN * p2mfle)
- p2mfl.extend(struct.unpack('%dL' % p2mfle, p2ms))
-
- self.p2mfl = p2mfl
-
- def flush(self):
- self.ofd.write(self.tail)
-
-class Writer(object):
- """compress a stream of checkpoints into a single image of the
- last checkpoint"""
- def __init__(self, fd, compact=False):
- self.fd = fd
- self.compact = compact
-
- self.vm = None
- self.tail = None
- # offset to first batch of pages
- self.imgstart = 0
- # PFN mappings
- self.pfns = []
-
- def __del__(self):
- self.close()
-
- def writeheader(self):
- hlen = struct.pack('!i', len(self.vm.header))
- header = ''.join([SIGNATURE, hlen, self.vm.header])
- self.fd.write(header)
-
- def writep2mfl(self):
- p2m = [struct.pack('L', self.vm.nr_pfns)]
- if self.vm.p2mext:
- p2m.extend([struct.pack('L', P2M_EXT_SIG), self.vm.p2mext])
- p2m.append(struct.pack('%dL' % len(self.vm.p2mfl), *self.vm.p2mfl))
- self.fd.write(''.join(p2m))
-
- def writebatch(self, batch):
- def offset(pfn):
- isz = (pfn / BATCH_SIZE + 1) * IDXLEN
- return self.imgstart + isz + pfn * PAGE_SIZE
-
- if not self.compact:
- return self.fd.write(batch)
-
- batch = parsebatch(batch)
- # sort pages for better disk seek behaviour
- batch.sort(lambda x, y: cmp(x[0] & ~LTAB_MASK, y[0] & ~LTAB_MASK))
-
- for pfndesc, page in batch:
- pfn = pfndesc & ~LTAB_MASK
- if pfn > self.vm.nr_pfns:
- log.error('INVALID PFN: %d' % pfn)
- if len(self.pfns) <= pfn:
- self.pfns.extend([0] * (pfn - len(self.pfns) + 1))
- self.pfns[pfn] = pfndesc
- self.fd.seek(offset(pfn))
- self.fd.write(page)
-
- #print "max offset: %d, %d" % (len(self.pfns), offset(self.pfns[-1]))
-
- def writeindex(self):
- "Write batch header in front of each page"
- hdrlen = INTLEN + BATCH_SIZE * LONGLEN
- batches = (len(self.pfns) + BATCH_SIZE - 1) / BATCH_SIZE
-
- for i in xrange(batches):
- offset = self.imgstart + i * (hdrlen + (PAGE_SIZE * BATCH_SIZE))
- pfnoff = i * BATCH_SIZE
- # python auto-clamps overreads
- pfns = self.pfns[pfnoff:pfnoff + BATCH_SIZE]
-
- self.fd.seek(offset)
- self.fd.write(struct.pack('i', len(pfns)))
- self.fd.write(struct.pack('%dL' % len(pfns), *pfns))
-
- def slurp(self, ifd):
- """Apply an incremental checkpoint to a loaded image.
- accepts a path or a file object."""
- if isinstance(ifd, str):
- ifd = file(ifd, 'rb')
-
- if not self.vm:
- self.vm = VMImage(ifd)
- self.writeheader()
-
- self.vm.readp2mfl()
- self.writep2mfl()
- self.imgstart = self.fd.tell()
-
- while True:
- l, batch = readbatch(ifd)
- if l <= 0:
- break
- self.writebatch(batch)
- self.tail = batch + ifd.read()
-
- def flush(self):
- if self.tail:
- self.fd.seek(0, 2)
- self.fd.write(self.tail)
- if self.compact:
- self.writeindex()
- self.tail = None
-
- def close(self):
- self.flush()
-
-def parseheader(header):
- "parses a header sexpression"
- return vm.parsedominfo(vm.strtosxpr(header))
-
-def makeheader(dominfo):
- "create an image header from a VM dominfo sxpr"
- items = [SIGNATURE]
- sxpr = vm.sxprtostr(dominfo)
- items.append(struct.pack('!i', len(sxpr)))
- items.append(sxpr)
- return ''.join(items)
-
-def readbatch(fd):
- batch = []
- batchlen = fd.read(INTLEN)
- batch.append(batchlen)
- batchlen, = struct.unpack('i', batchlen)
- log.info("batch length: %d" % batchlen)
- if batchlen <= 0:
- return (batchlen, batch[0])
-
- batchfns = fd.read(LONGLEN * batchlen)
- batch.append(batchfns)
- pages = fd.read(PAGE_SIZE * batchlen)
- if len(pages) != PAGE_SIZE * batchlen:
- log.error('SHORT READ: %d' % len(pages))
- batch.append(pages)
-
- return (batchlen, ''.join(batch))
-
-def parsebatch(batch):
- "parse a batch string into pages"
- batchlen, batch = batch[:INTLEN], batch[INTLEN:]
- batchlen, = struct.unpack('i', batchlen)
- #print 'batch length: %d' % batchlen
- pfnlen = batchlen * LONGLEN
- pfns = struct.unpack('%dL' % batchlen, batch[:pfnlen])
- pagebuf = batch[pfnlen:]
- pages = [pagebuf[i*PAGE_SIZE:(i+1)*PAGE_SIZE] for i in xrange(batchlen)]
- return zip(pfns, pages)
diff -r d681b8ed0d03 -r dc243b689336 tools/python/xen/remus/save.py
--- a/tools/python/xen/remus/save.py Mon Jun 06 04:40:39 2011 -0700
+++ b/tools/python/xen/remus/save.py Mon Jun 06 04:40:42 2011 -0700
@@ -10,7 +10,7 @@
import xen.lowlevel.checkpoint
-import vm, image
+import vm
class _proxy(object):
"proxy simulates an object without inheritance"
@@ -68,7 +68,7 @@
def start(self):
vm.getshadowmem(self.vm)
- hdr = image.makeheader(self.vm.dominfo)
+ hdr = vm.makeheader(self.vm.dominfo)
self.fd.write(hdr)
self.fd.flush()
diff -r d681b8ed0d03 -r dc243b689336 tools/python/xen/remus/vm.py
--- a/tools/python/xen/remus/vm.py Mon Jun 06 04:40:39 2011 -0700
+++ b/tools/python/xen/remus/vm.py Mon Jun 06 04:40:42 2011 -0700
@@ -1,6 +1,6 @@
#!/usr/bin/env python
-import xmlrpclib
+import xmlrpclib, struct
from xen.xend.XendClient import server
from xen.xend import sxp, osdep
@@ -11,6 +11,7 @@
# need a nicer way to load disk drivers
import vbd
+SIGNATURE = 'LinuxGuestRecord'
class VMException(Exception): pass
class VM(object):
@@ -162,3 +163,11 @@
# target is in MB, not KB
target = (dom0cur - needed) / 1024
server.xend.domain.setMemoryTarget(0, target)
+
+def makeheader(dominfo):
+ "create an image header from a VM dominfo sxpr"
+ items = [SIGNATURE]
+ sxpr = sxprtostr(dominfo)
+ items.append(struct.pack('!i', len(sxpr)))
+ items.append(sxpr)
+ return ''.join(items)
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