[PATCH] lsmem: fix total online/offline memory calculation

* [PATCH] lsmem: fix total online/offline memory calculation
@ 2018-03-20 16:17 Gerald Schaefer
  2018-03-20 17:47 ` Gerald Schaefer
  0 siblings, 1 reply; 3+ messages in thread
From: Gerald Schaefer @ 2018-03-20 16:17 UTC (permalink / raw)
  To: util-linux; +Cc: wild, gerald.schaefer

lsmem currently calculates the total online/offline memory by iterating
over all lsmem->blocks. Depending on the lsmem options, there may be
only one lsmem->block, because all sysfs memory blocks could be merged
into one. In this case, the calculation is wrong, because the individual
online/offline state of the sysfs memory blocks is not preserved, but
rather lsmem->blocks[0].state is set to the state of the first sysfs
memory block, typically MEMORY_STATE_ONLINE (at least on s390).

This means that "Total offline memory" will always be calculated as 0
in such cases, e.g. when using "lsmem --summary", or any options that
would merge the table output to one line, like "lsmem -o RANGE":

~# lsmem --summary
Memory block size:         1G
Total online memory:      20G
Total offline memory:      0B

Adding the "-a" option shows the real summary, since there is no block
merging going on, and the calculation is therefore correct:

~# lsmem -a --summary
Memory block size:         1G
Total online memory:      16G
Total offline memory:      4G

Fix this by moving the online/offline calculation into the loop that
is iterating over all sysfs memory blocks, instead of iterating over
potentially merged lsmem->blocks.

Reported-by: Andre Wild <wild@linux.vnet.ibm.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
---
 sys-utils/lsmem.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/sys-utils/lsmem.c b/sys-utils/lsmem.c
index 3e06e43be74e..517207431c83 100644
--- a/sys-utils/lsmem.c
+++ b/sys-utils/lsmem.c
@@ -443,6 +443,10 @@ static void read_info(struct lsmem *lsmem)
 
 	for (i = 0; i < lsmem->ndirs; i++) {
 		memory_block_read_attrs(lsmem, lsmem->dirs[i]->d_name, &blk);
+		if (blk.state == MEMORY_STATE_ONLINE)
+			lsmem->mem_online += lsmem->block_size;
+		else
+			lsmem->mem_offline += lsmem->block_size;
 		if (is_mergeable(lsmem, &blk)) {
 			lsmem->blocks[lsmem->nblocks - 1].count++;
 			continue;
@@ -451,12 +455,6 @@ static void read_info(struct lsmem *lsmem)
 		lsmem->blocks = xrealloc(lsmem->blocks, lsmem->nblocks * sizeof(blk));
 		*&lsmem->blocks[lsmem->nblocks - 1] = blk;
 	}
-	for (i = 0; i < lsmem->nblocks; i++) {
-		if (lsmem->blocks[i].state == MEMORY_STATE_ONLINE)
-			lsmem->mem_online += lsmem->block_size * lsmem->blocks[i].count;
-		else
-			lsmem->mem_offline += lsmem->block_size * lsmem->blocks[i].count;
-	}
 }
 
 static int memory_block_filter(const struct dirent *de)
-- 
2.13.5


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