[PATCH v2] makedumpfile: Add description of pages lost by ENOSPACE in IMPLEMENTATION

[Zhou Wenjian]

Currently, there is no obvious description in IMPLEMENTATION for
distinguishing the lost pages resulted by ENOSPACE errors or others.
So, it is added.

Signed-off-by: Zhou Wenjian <zhouwj-fnst at cn.fujitsu.com>
---
 IMPLEMENTATION |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/IMPLEMENTATION b/IMPLEMENTATION
index 72df5d5..589c5bf 100644
--- a/IMPLEMENTATION
+++ b/IMPLEMENTATION
@@ -240,6 +240,10 @@
     The page header and page data are written in pairs. When writing page data
     (pfn N+1), if ENOSPACE error happens, the page headers after N won't be
     written either.
+    Since the data lost is filled with zero when it is read, the page_desc->offset
+    will also be zero. And zero page has its own offset not equal 0. So when reading
+    page from incomplete core, only the page lost by ENOSPACE errors has 0 in its
+    corresponding page descriptor's member offset.
 
     If there is no page data dumped into the DUMPFILE, the DUMPFILE can't be
     analysed by crash.
-- 
1.7.1