From: David Vrabel <david.vrabel@citrix.com>
To: Wei Liu <wei.liu2@citrix.com>
Cc: "Keir (Xen.org)" <keir@xen.org>,
Ian Campbell <Ian.Campbell@citrix.com>,
"jbeulich@suse.com" <jbeulich@suse.com>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: [RFC PATCH V4 11/18] Bump EVTCHNS_PER_BUCKET to 512
Date: Fri, 15 Mar 2013 18:43:21 +0000 [thread overview]
Message-ID: <51436BC9.7000108@citrix.com> (raw)
In-Reply-To: <1363372620.29093.185.camel@zion.uk.xensource.com>
On 15/03/13 18:37, Wei Liu wrote:
> On Fri, 2013-03-15 at 18:15 +0000, David Vrabel wrote:
>> On 05/03/13 12:30, Wei Liu wrote:
>>> For 64 bit build and 3-level event channel and the original value of
>>> EVTCHNS_PER_BUCKET (128), the space needed to accommodate d->evtchn would be 4
>>> pages (PAGE_SIZE = 4096). Given that not every domain needs 3-level event
>>> channel, this leads to waste of memory. Having EVTCHN_PER_BUCKETS to be 512
>>> can occupy exact one page.
>>
>> This makes the list of buckets a page in size but each bucket is now 4
>> pages.
>>
>
> I'm confused.
3 pages (not 4) with flask, 2 pages without.
> On 64 bit w/ FLASK enabled, sizeof(struct evtchn) = 18B, bucket size =
> 9216B = 2.25 pages; w/o FLASK enabled, sizeof(struct evtchn) = 10B,
> bucket size = 5120B = 1.25 pages.
struct evtchn isn't packed so it is 24 bytes with flask and 16 without.
David
next prev parent reply other threads:[~2013-03-15 18:43 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-05 12:30 [RFC PATCH V4] Implement 3-level event channel ABI in Xen Wei Liu
2013-03-05 12:30 ` [RFC PATCH V4 01/18] xen: correct BITS_PER_EVTCHN_WORD on arm Wei Liu
2013-03-05 12:30 ` [RFC PATCH V4 02/18] Clean up trailing whitespaces Wei Liu
2013-03-05 12:30 ` [RFC PATCH V4 03/18] Dynamically allocate d->evtchn Wei Liu
2013-03-05 12:30 ` [RFC PATCH V4 04/18] Move event channel macros / struct definition to proper place Wei Liu
2013-03-05 12:30 ` [RFC PATCH V4 05/18] Add d->max_evtchns Wei Liu
2013-03-05 12:30 ` [RFC PATCH V4 06/18] Add evtchn_is_{pending, masked} and evtchn_clear_pending Wei Liu
2013-03-05 12:30 ` [RFC PATCH V4 07/18] Implement extended event channel ABIs query Wei Liu
2013-03-05 12:30 ` [RFC PATCH V4 08/18] Define 3-level event channel registration interface Wei Liu
2013-03-05 12:30 ` [RFC PATCH V4 09/18] Add evtchn_extended in struct domain Wei Liu
2013-03-05 12:30 ` [RFC PATCH V4 10/18] Calculate max event channels for EVTCHN_EXTENDED_L3 Wei Liu
2013-03-05 12:30 ` [RFC PATCH V4 11/18] Bump EVTCHNS_PER_BUCKET to 512 Wei Liu
2013-03-15 18:15 ` David Vrabel
2013-03-15 18:37 ` Wei Liu
2013-03-15 18:43 ` David Vrabel [this message]
2013-03-05 12:30 ` [RFC PATCH V4 12/18] Update Xen public header xen.h Wei Liu
2013-03-05 12:30 ` [RFC PATCH V4 13/18] Genneralized event channel operations Wei Liu
2013-03-05 12:30 ` [RFC PATCH V4 14/18] Introduce EVTCHN_WORD_BITORDER macro Wei Liu
2013-03-05 12:30 ` [RFC PATCH V4 15/18] Infrastructure to manipulate 3-level event channel pages Wei Liu
2013-03-05 14:22 ` Jan Beulich
2013-03-05 12:30 ` [RFC PATCH V4 16/18] Implement 3-level event channel routines Wei Liu
2013-03-05 14:28 ` Jan Beulich
2013-03-05 16:07 ` Wei Liu
2013-03-05 16:13 ` Jan Beulich
2013-03-05 12:30 ` [RFC PATCH V4 17/18] Only allow extended event channel on Dom0 and driver domains Wei Liu
2013-03-05 12:30 ` [RFC PATCH V4 18/18] libxl: add evtchn_extended_allowed flag Wei Liu
2013-03-05 13:48 ` Ian Jackson
2013-03-05 17:11 ` Wei Liu
2013-03-05 17:38 ` Ian Jackson
2013-03-05 17:51 ` Wei Liu
2013-03-05 17:56 ` David Vrabel
2013-03-05 18:08 ` Wei Liu
2013-03-06 17:16 ` Wei Liu
2013-03-07 11:23 ` David Vrabel
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