linux-kernel - Re: percpu allocation failures

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Date:   Wed, 27 Sep 2017 10:05:44 +0100
From:   Luis Henriques <lhenriques@...e.com>
To:     Dennis Zhou <dennisszhou@...il.com>
Cc:     Tejun Heo <tj@...nel.org>, Christoph Lameter <cl@...ux.com>,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: percpu allocation failures

Dennis Zhou <dennisszhou@...il.com> writes:

> Hi Luis,
>
> This seems to be an issue with the reserved chunk being unable to
> allocate memory when loading kernel modules. Unfortunately, I have not 
> been successful in reproducing this with the reserved chunk allocation
> path exposed or by inserting the nft_meta module.
>
> Could you please send me the output when ran with the following patch
> and the output of the percpu memory statistics file before and after
> inserting the module (PERCPU_STATS)? The stats are in
> /sys/kernel/debug/percpu_stats.

Please find attached all the info you requested.  Hope it helps.

Also, here's the nft script I'm using to trigger the issue locally:

#!/usr/sbin/nft -f

flush ruleset

table inet filter {
	chain input {
		type filter hook input priority 0;
		iif lo accept
		ct state established,related accept
		tcp dport { 22 } ct state new accept
		ip6 nexthdr icmpv6 icmpv6 type { nd-neighbor-solicit,  nd-router-advert, nd-neighbor-advert } accept
		counter drop
	}
}

Cheers,
-- 
Luis


Download attachment "percpu_stats.before" of type "application/octet-stream" (2031 bytes)

Download attachment "percpu_stats.after" of type "application/octet-stream" (2031 bytes)

Download attachment "dmesg.debug" of type "application/octet-stream" (5911 bytes)