From: Juergen Gross <jgross@suse.com>
To: Dario Faggioli <dario.faggioli@citrix.com>,
Wei Liu <wei.liu2@citrix.com>
Cc: Xen-devel <xen-devel@lists.xenproject.org>,
Ian Jackson <Ian.Jackson@eu.citrix.com>,
Ian Campbell <ian.campbell@citrix.com>
Subject: Re: [PATCH v3 10/10] libxl: fix caller of libxl_cpupool functions
Date: Thu, 16 Jul 2015 11:30:00 +0200 [thread overview]
Message-ID: <55A77998.9090307@suse.com> (raw)
In-Reply-To: <1437037044.13522.219.camel@citrix.com>
On 07/16/2015 10:57 AM, Dario Faggioli wrote:
> [Adding Juergen]
Near miss. You took my old mail address. :-)
>
> On Wed, 2015-07-15 at 18:16 +0100, Wei Liu wrote:
>> On Tue, Jul 14, 2015 at 06:33:22PM +0100, Ian Jackson wrote:
>>> Wei Liu writes ("[PATCH v3 10/10] libxl: fix caller of libxl_cpupool functions"):
>
>>>> --- a/tools/libxl/libxl.c
>>>> +++ b/tools/libxl/libxl.c
>>>> @@ -771,8 +771,11 @@ libxl_cpupoolinfo * libxl_list_cpupool(libxl_ctx *ctx, int *nb_pool_out)
>>>>
>>>> poolid = 0;
>>>> for (i = 0;; i++) {
>>>> - if (cpupool_info(gc, &info, poolid, false))
>>>> + libxl_cpupoolinfo_init(&info);
>>>> + if (cpupool_info(gc, &info, poolid, false)) {
>>>> + libxl_cpupoolinfo_dispose(&info);
>>>> break;
>>>> + }
>>>
>>> I'm not convinced by this change.
>>>
>>> I think that this function has broken error handling: if cpupool_info
>>> fails, it simply ignores the error.
>>>
>>
>> I think the semantics of this function is to get back as many cpupool
>> info as it can.
>>
> Yes, I also think this is the case.
Indeed.
>> Unfortunately the failing of cpupool_info can either mean the cpupool id
>> does not exist or other internal errors. So not cleaning up is the
>> right thing to do (speaking from semantics point of view).
>>
> Indeed.
>
>> I think I need to overhaul cpupool_info a bit if we want to make this
>> API better.
>>
> Well, perhaps having cpupool_info() treating specially the situation
> where the pool ID is not there may help... However, what would you do
> once you have this additional piece of information available?
>
> Maybe, depending on the error, we can cleanup the whole array? Is it
> this that we are after?
I think the best would be:
Modify cpupool_info() to return either success, internal error, or no
cpupool found.
In case of internal error libxl_list_cpupool() should clean up and
return NULL.
>
>> I'm not sure if it is possible to interleave pool ids. If so, we need a
>> way to get back the exact number of cpupools. Dario?
libxl_list_cpupool() does that (2nd parameter).
>>
> Sorry, what you mean by 'interleave pool ids'?
Not sure if this is an answer to interleaving of pool ids, but it is
possible to specify the pool id when creating a new cpupool at the
libxc interface. Even in case this is not used, pool ids can easily
be sparse after having deleted a cpupool.
Juergen
next prev parent reply other threads:[~2015-07-16 9:30 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-14 16:41 [PATCH v3 00/10] xl/libxl: fix issues discovered by coverity Wei Liu
2015-07-14 16:41 ` [PATCH v3 01/10] libxl: don't check s!=NULL in libxl__abs_path Wei Liu
2015-07-14 17:19 ` Ian Jackson
2015-07-14 16:41 ` [PATCH v3 02/10] libxl: turn two malloc's to libxl__malloc Wei Liu
2015-07-14 17:19 ` Ian Jackson
2015-07-14 16:41 ` [PATCH v3 03/10] libxl: make libxl__strdup handle NULL Wei Liu
2015-07-14 17:21 ` Ian Jackson
2015-07-14 16:41 ` [PATCH v3 04/10] libxl: avoid leaking in libxl__initia_device_remove Wei Liu
2015-07-14 17:21 ` Ian Jackson
2015-07-14 16:41 ` [PATCH v3 05/10] libxl: localtime(3) can return NULL Wei Liu
2015-07-14 17:22 ` Ian Jackson
2015-07-14 16:41 ` [PATCH v3 06/10] libxl: qmp_init_handler " Wei Liu
2015-07-14 17:23 ` Ian Jackson
2015-07-14 16:41 ` [PATCH v3 07/10] xl: correct handling of extra_config in main_cpupoolcreate Wei Liu
2015-07-14 17:23 ` Ian Jackson
2015-09-11 10:59 ` Ian Jackson
2015-07-14 16:41 ` [PATCH v3 08/10] xl: correctly handle null extra config in main_config_update Wei Liu
2015-07-14 17:23 ` Ian Jackson
2015-07-14 16:41 ` [PATCH v3 09/10] xl: fix a typo in error string in create_domain Wei Liu
2015-07-14 17:24 ` Ian Jackson
2015-07-14 16:41 ` [PATCH v3 10/10] libxl: fix caller of libxl_cpupool functions Wei Liu
2015-07-14 17:33 ` Ian Jackson
2015-07-15 17:16 ` Wei Liu
2015-07-16 8:57 ` Dario Faggioli
2015-07-16 9:07 ` Wei Liu
2015-07-16 9:33 ` Juergen Gross
2015-07-16 9:30 ` Juergen Gross [this message]
2015-07-16 12:49 ` Dario Faggioli
2015-07-15 10:23 ` [PATCH v3 00/10] xl/libxl: fix issues discovered by coverity Ian Campbell
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