From: Alasdair G Kergon <agk@redhat.com>
To: Mikulas Patocka <mpatocka@redhat.com>,
"Zhang, Yanmin" <yanmin_zhang@linux.intel.com>,
"xinhui.pan" <xinhuix.pan@intel.com>,
linux-kernel@vger.kernel.org, agk@redhat.com, snitzer@redhat.com,
dm-devel@redhat.com, "Liu, ShuoX" <shuox.liu@intel.com>
Subject: Re: [dm-devel] [PATCH] md/dm-ioctl.c: optimize memory allocation in copy_params
Date: Wed, 23 Jul 2014 13:54:07 +0100 [thread overview]
Message-ID: <20140723125407.GG6822@agk-dp.fab.redhat.com> (raw)
In-Reply-To: <alpine.LRH.2.02.1407230816000.29551@file01.intranet.prod.int.rdu2.redhat.com>
On Wed, Jul 23, 2014 at 08:16:58AM -0400, Mikulas Patocka wrote:
> So, it means that you do not use device mapper at all. So, why are you
> trying to change memory allocation in device mapper?
So the *test* they run is asking device-mapper to briefly reserve a 64KB
buffer when there is no data to report: The answer is not to run that
pointless test:)
And if a single 64KB allocation really is a big deal, then patch 'vold'
in userspace so it doesn't ask for 64KB when it clearly doesn't need it!
+ int Devmapper::dumpState(SocketClient *c) {
+ char *buffer = (char *) malloc(1024 * 64);
The code has just
#define DEVMAPPER_BUFFER_SIZE 4096
for all the other dm ioctls it issues.
Only use a larger value when it is needed i.e. if DM_BUFFER_FULL_FLAG gets set.
Alasdair
next prev parent reply other threads:[~2014-07-23 12:54 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-04 10:22 [PATCH] md/dm-ioctl.c: optimize memory allocation in copy_params xinhui.pan
2014-07-08 22:39 ` [dm-devel] " Mikulas Patocka
2014-07-09 2:01 ` Zhang, Yanmin
2014-07-09 3:37 ` xinhui.pan
2014-07-09 14:53 ` Mikulas Patocka
2014-07-22 1:02 ` Zhang, Yanmin
2014-07-22 1:23 ` Alasdair G Kergon
2014-07-22 2:04 ` Alasdair G Kergon
2014-07-23 3:15 ` Zhang, Yanmin
2014-07-23 3:06 ` Zhang, Yanmin
2014-07-23 12:16 ` Mikulas Patocka
2014-07-23 12:54 ` Alasdair G Kergon [this message]
2014-07-23 17:14 ` Mikulas Patocka
2014-07-24 5:53 ` Zhang, Yanmin
2014-07-23 12:39 ` Mikulas Patocka
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