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From: Gerald Schaefer <gerald.schaefer@de.ibm.com>
To: util-linux@vger.kernel.org
Cc: wild@linux.vnet.ibm.com, gerald.schaefer@de.ibm.com
Subject: [PATCH] lsmem: fix total online/offline memory calculation
Date: Tue, 20 Mar 2018 17:17:38 +0100	[thread overview]
Message-ID: <20180320161738.49439-1-gerald.schaefer@de.ibm.com> (raw)

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


             reply	other threads:[~2018-03-20 16:18 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-20 16:17 Gerald Schaefer [this message]
2018-03-20 17:47 ` [PATCH] lsmem: fix total online/offline memory calculation Gerald Schaefer
2018-03-20 17:57   ` Karel Zak

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