From: Al Viro <viro@zeniv.linux.org.uk>
To: kernel test robot <rong.a.chen@intel.com>
Cc: David Howells <dhowells@redhat.com>,
Hugh Dickins <hughd@google.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-fsdevel@vger.kernel.org, lkp@01.org
Subject: Re: [vfs] 8bb3c61baf: vm-scalability.median -23.7% regression
Date: Mon, 9 Sep 2019 00:47:22 +0100 [thread overview]
Message-ID: <20190908234722.GE1131@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20190908214601.GC1131@ZenIV.linux.org.uk>
On Sun, Sep 08, 2019 at 10:46:01PM +0100, Al Viro wrote:
> On Tue, Sep 03, 2019 at 04:41:22PM +0800, kernel test robot wrote:
> > Greeting,
> >
> > FYI, we noticed a -23.7% regression of vm-scalability.median due to commit:
> >
> >
> > commit: 8bb3c61bafa8c1cd222ada602bb94ff23119e738 ("vfs: Convert ramfs, shmem, tmpfs, devtmpfs, rootfs to use the new mount API")
> > https://kernel.googlesource.com/pub/scm/linux/kernel/git/viro/vfs.git work.mount
> >
> > in testcase: vm-scalability
> > on test machine: 88 threads Intel(R) Xeon(R) CPU E5-2699 v4 @ 2.20GHz with 128G memory
> > with following parameters:
> >
> > runtime: 300s
> > size: 16G
> > test: shm-pread-rand
> > cpufreq_governor: performance
> > ucode: 0xb000036
>
> That thing loses size=... option. Both size= and nr_blocks= affect the
> same thing (->max_blocks), but the parser keeps track of the options
> it has seen and applying the parsed data to superblock checks only
> whether nr_blocks= had been there. IOW, size= gets parsed, but the
> result goes nowhere.
>
> I'm not sure whether it's better to fix the patch up or redo it from
> scratch - it needs to be carved up anyway and it's highly non-transparent,
> so I'm probably going to replace the damn thing entirely with something
> that would be easier to follow.
... and this
+ { Opt_huge, "deny", SHMEM_HUGE_DENY },
+ { Opt_huge, "force", SHMEM_HUGE_FORCE },
had been wrong - huge=deny and huge=force should not be accepted _and_
fs_parameter_enum is not suitable for negative constants right now
anyway.
next prev parent reply other threads:[~2019-09-08 23:47 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190903084122.GH15734@shao2-debian>
2019-09-08 21:46 ` [vfs] 8bb3c61baf: vm-scalability.median -23.7% regression Al Viro
2019-09-08 23:47 ` Al Viro [this message]
2019-09-09 3:10 ` Hugh Dickins
2019-09-09 3:56 ` Al Viro
2019-09-10 6:27 ` Hugh Dickins
2019-09-11 3:05 ` Hugh Dickins
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