qcow2: mark the memory as no longer needed after qcow2_cache_empty()

After having emptied the cache, the data in the cache tables is no
longer useful, so we can tell the kernel that we are done with it. In
Linux this frees the resources associated with it.

The effect of this can be seen in the HMP commit operation: it moves
data from the top to the base image (and fills both caches), then it
empties the top image. At this point the data in that cache is no
longer needed so it's just wasting memory.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 08538b098e1faf6c92496477cf9b47a20e5aacea.1438690126.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
1 file changed
tree: 1c7ef0bb90784bb806bc54c04c62f0fb33524520
  1. audio/
  2. backends/
  3. block/
  4. bsd-user/
  5. crypto/
  6. default-configs/
  7. disas/
  8. docs/
  9. fpu/
  10. fsdev/
  11. gdb-xml/
  12. hw/
  13. include/
  14. libcacard/
  15. libdecnumber/
  16. linux-headers/
  17. linux-user/
  18. migration/
  19. net/
  20. pc-bios/
  21. po/
  22. qapi/
  23. qga/
  24. qobject/
  25. qom/
  26. roms/
  27. scripts/
  28. slirp/
  29. stubs/
  30. target-alpha/
  31. target-arm/
  32. target-cris/
  33. target-i386/
  34. target-lm32/
  35. target-m68k/
  36. target-microblaze/
  37. target-mips/
  38. target-moxie/
  39. target-openrisc/
  40. target-ppc/
  41. target-s390x/
  42. target-sh4/
  43. target-sparc/
  44. target-tricore/
  45. target-unicore32/
  46. target-xtensa/
  47. tcg/
  48. tests/
  49. trace/
  50. ui/
  51. util/
  52. .exrc
  53. .gitignore
  54. .gitmodules
  55. .mailmap
  56. .travis.yml
  57. accel.c
  58. aio-posix.c
  59. aio-win32.c
  60. arch_init.c
  61. async.c
  62. balloon.c
  63. block.c
  64. blockdev-nbd.c
  65. blockdev.c
  66. blockjob.c
  67. bootdevice.c
  68. bt-host.c
  69. bt-vhci.c
  70. Changelog
  71. CODING_STYLE
  72. configure
  73. COPYING
  74. COPYING.LIB
  75. coroutine-gthread.c
  76. coroutine-sigaltstack.c
  77. coroutine-ucontext.c
  78. coroutine-win32.c
  79. cpu-exec.c
  80. cpus.c
  81. cputlb.c
  82. device-hotplug.c
  83. device_tree.c
  84. disas.c
  85. dma-helpers.c
  86. dump.c
  87. exec.c
  88. gdbstub.c
  89. HACKING
  90. hmp-commands.hx
  91. hmp.c
  92. hmp.h
  93. iohandler.c
  94. ioport.c
  95. iothread.c
  96. kvm-all.c
  97. kvm-stub.c
  98. LICENSE
  99. main-loop.c
  100. MAINTAINERS
  101. Makefile
  102. Makefile.objs
  103. Makefile.target
  104. memory.c
  105. memory_mapping.c
  106. module-common.c
  107. monitor.c
  108. nbd.c
  109. numa.c
  110. os-posix.c
  111. os-win32.c
  112. page_cache.c
  113. qapi-schema.json
  114. qdev-monitor.c
  115. qdict-test-data.txt
  116. qemu-bridge-helper.c
  117. qemu-char.c
  118. qemu-coroutine-io.c
  119. qemu-coroutine-lock.c
  120. qemu-coroutine-sleep.c
  121. qemu-coroutine.c
  122. qemu-doc.texi
  123. qemu-ga.texi
  124. qemu-img-cmds.hx
  125. qemu-img.c
  126. qemu-img.texi
  127. qemu-io-cmds.c
  128. qemu-io.c
  129. qemu-log.c
  130. qemu-nbd.c
  131. qemu-nbd.texi
  132. qemu-options-wrapper.h
  133. qemu-options.h
  134. qemu-options.hx
  135. qemu-seccomp.c
  136. qemu-tech.texi
  137. qemu-timer.c
  138. qemu.nsi
  139. qemu.sasl
  140. qjson.c
  141. qmp-commands.hx
  142. qmp.c
  143. qtest.c
  144. README
  145. rules.mak
  146. softmmu_template.h
  147. spice-qemu-char.c
  148. tcg-runtime.c
  149. tci.c
  150. thread-pool.c
  151. thunk.c
  152. tpm.c
  153. trace-events
  154. translate-all.c
  155. translate-all.h
  156. user-exec.c
  157. VERSION
  158. version.rc
  159. vl.c
  160. xen-common-stub.c
  161. xen-common.c
  162. xen-hvm-stub.c
  163. xen-hvm.c
  164. xen-mapcache.c