57 lines
1.9 KiB
Diff
57 lines
1.9 KiB
Diff
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From b13a2f3c2885bc638d1e413ef9e7c59a8ec8f81d Mon Sep 17 00:00:00 2001
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From: Lianbo Jiang <lijiang@redhat.com>
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Date: Tue, 14 Feb 2023 22:37:08 +0800
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Subject: [PATCH 74/89] Fix for "kmem -i" option to not print invalid values
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for CACHED
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The "kmem -i" option may output a bogus statistics for CACHED, which
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might be observed when some extreme situations occur in kernel, such as
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OOM, disk IO errors, etc.
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The following result of calculation may be a negative value, refer to
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the dump_kmeminfo():
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page_cache_size = nr_file_pages - swapper_space_nrpages - buffer_pages;
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As a result, the negative value will be converted to unsigned long
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integer, eventually it overflows and is printed as big integers.
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crash> kmem -i
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PAGES TOTAL PERCENTAGE
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TOTAL MEM 255314511 973.9 GB ----
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FREE 533574 2 GB 0% of TOTAL MEM
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USED 254780937 971.9 GB 99% of TOTAL MEM
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SHARED 1713 6.7 MB 0% of TOTAL MEM
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BUFFERS 374 1.5 MB 0% of TOTAL MEM
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CACHED -114 70368744177664 GB 72251060080% of TOTAL MEM
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^^^^ ^^^^^^^^^^^^^^ ^^^^^^^^^^^^
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...
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Let's normalize it to zero with an info message to fix such cornor cases.
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Reported-by: Buland Kumar Singh <bsingh@redhat.com>
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Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
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Signed-off-by: Kazuhito Hagio <k-hagio-ab@nec.com>
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---
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memory.c | 5 +++++
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1 file changed, 5 insertions(+)
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diff --git a/memory.c b/memory.c
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index e0742c1bd3a4..d9cd616f19de 100644
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--- a/memory.c
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+++ b/memory.c
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@@ -8615,6 +8615,11 @@ dump_kmeminfo(void)
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page_cache_size = 0;
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+ if (page_cache_size < 0) {
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+ error(INFO, "page_cache_size went negative (%ld), setting to 0\n",
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+ page_cache_size);
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+ page_cache_size = 0;
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+ }
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pct = (page_cache_size * 100)/totalram_pages;
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fprintf(fp, "%13s %7ld %11s %3ld%% of TOTAL MEM\n",
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"CACHED", page_cache_size,
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--
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2.37.1
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