From: Xiao Guangrong <guangrong.xiao@linux.intel.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: pbonzini@redhat.com, imammedo@redhat.com, gleb@kernel.org,
mtosatti@redhat.com, stefanha@redhat.com, rth@twiddle.net,
ehabkost@redhat.com, dan.j.williams@intel.com,
kvm@vger.kernel.org, qemu-devel@nongnu.org
Subject: Re: [PATCH v6 09/33] exec: allow file_ram_alloc to work on file
Date: Mon, 9 Nov 2015 18:48:12 +0800 [thread overview]
Message-ID: <564079EC.6010804@linux.intel.com> (raw)
In-Reply-To: <20151109120731-mutt-send-email-mst@redhat.com>
On 11/09/2015 06:13 PM, Michael S. Tsirkin wrote:
> On Fri, Oct 30, 2015 at 01:56:03PM +0800, Xiao Guangrong wrote:
>> Currently, file_ram_alloc() only works on directory - it creates a file
>> under @path and do mmap on it
>>
>> This patch tries to allow it to work on file directly, if @path is a
>> directory it works as before, otherwise it treats @path as the target
>> file then directly allocate memory from it
>>
>> Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
>> ---
>> exec.c | 80 ++++++++++++++++++++++++++++++++++++++++++------------------------
>> 1 file changed, 51 insertions(+), 29 deletions(-)
>>
>> diff --git a/exec.c b/exec.c
>> index 3ca7e50..f219010 100644
>> --- a/exec.c
>> +++ b/exec.c
>> @@ -1174,14 +1174,60 @@ void qemu_mutex_unlock_ramlist(void)
>> }
>>
>> #ifdef __linux__
>> +static bool path_is_dir(const char *path)
>> +{
>> + struct stat fs;
>> +
>> + return stat(path, &fs) == 0 && S_ISDIR(fs.st_mode);
>
> This means file doesn't exist is treated as a file.
> Can't figure out if that's intentional, should
> be documented in any case.
The path is dir only if it passes S_ISDIR test. Otherwise, it is treated
as regular file. Any error on the file will be figured out by open() and
mmap() later.
>
>> +}
>> +
>> +static int open_file_path(RAMBlock *block, const char *path, size_t size)
>> +{
>> + char *filename;
>> + char *sanitized_name;
>> + char *c;
>> + int fd;
>> +
>> + if (!path_is_dir(path)) {
>> + int flags = (block->flags & RAM_SHARED) ? O_RDWR : O_RDONLY;
>
> Why does this make sense?
RAM_SHARED means its write is invisible to others also it does not actual
change the content of the file. Readonly permission is enough for this case.
It is also help us to pass a readonly file to the guess but discard its change
after guest shutdown.
>
>> +
>> + flags |= O_EXCL;
>
> And why does this makes sense?
It' used if we pass a block device as a NVDIMM backend memory:
O_EXCL can be used without O_CREAT if pathname refers to a block
device. If the block device is in use by the system (e.g., mounted),
open() fails with the error EBUSY
BTW, the similar logic has already been in upsteam QEMU which is
introduced by commit 8d31d6b6 (backends/hostmem-file: Allow to specify
full pathname for backing file). I will drop these patches:
util: introduce qemu_file_get_page_size()
exec: allow memory to be allocated from any kind of path
exec: allow file_ram_alloc to work on file
WARNING: multiple messages have this Message-ID (diff)
From: Xiao Guangrong <guangrong.xiao@linux.intel.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: ehabkost@redhat.com, kvm@vger.kernel.org, gleb@kernel.org,
mtosatti@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com,
imammedo@redhat.com, pbonzini@redhat.com,
dan.j.williams@intel.com, rth@twiddle.net
Subject: Re: [Qemu-devel] [PATCH v6 09/33] exec: allow file_ram_alloc to work on file
Date: Mon, 9 Nov 2015 18:48:12 +0800 [thread overview]
Message-ID: <564079EC.6010804@linux.intel.com> (raw)
In-Reply-To: <20151109120731-mutt-send-email-mst@redhat.com>
On 11/09/2015 06:13 PM, Michael S. Tsirkin wrote:
> On Fri, Oct 30, 2015 at 01:56:03PM +0800, Xiao Guangrong wrote:
>> Currently, file_ram_alloc() only works on directory - it creates a file
>> under @path and do mmap on it
>>
>> This patch tries to allow it to work on file directly, if @path is a
>> directory it works as before, otherwise it treats @path as the target
>> file then directly allocate memory from it
>>
>> Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
>> ---
>> exec.c | 80 ++++++++++++++++++++++++++++++++++++++++++------------------------
>> 1 file changed, 51 insertions(+), 29 deletions(-)
>>
>> diff --git a/exec.c b/exec.c
>> index 3ca7e50..f219010 100644
>> --- a/exec.c
>> +++ b/exec.c
>> @@ -1174,14 +1174,60 @@ void qemu_mutex_unlock_ramlist(void)
>> }
>>
>> #ifdef __linux__
>> +static bool path_is_dir(const char *path)
>> +{
>> + struct stat fs;
>> +
>> + return stat(path, &fs) == 0 && S_ISDIR(fs.st_mode);
>
> This means file doesn't exist is treated as a file.
> Can't figure out if that's intentional, should
> be documented in any case.
The path is dir only if it passes S_ISDIR test. Otherwise, it is treated
as regular file. Any error on the file will be figured out by open() and
mmap() later.
>
>> +}
>> +
>> +static int open_file_path(RAMBlock *block, const char *path, size_t size)
>> +{
>> + char *filename;
>> + char *sanitized_name;
>> + char *c;
>> + int fd;
>> +
>> + if (!path_is_dir(path)) {
>> + int flags = (block->flags & RAM_SHARED) ? O_RDWR : O_RDONLY;
>
> Why does this make sense?
RAM_SHARED means its write is invisible to others also it does not actual
change the content of the file. Readonly permission is enough for this case.
It is also help us to pass a readonly file to the guess but discard its change
after guest shutdown.
>
>> +
>> + flags |= O_EXCL;
>
> And why does this makes sense?
It' used if we pass a block device as a NVDIMM backend memory:
O_EXCL can be used without O_CREAT if pathname refers to a block
device. If the block device is in use by the system (e.g., mounted),
open() fails with the error EBUSY
BTW, the similar logic has already been in upsteam QEMU which is
introduced by commit 8d31d6b6 (backends/hostmem-file: Allow to specify
full pathname for backing file). I will drop these patches:
util: introduce qemu_file_get_page_size()
exec: allow memory to be allocated from any kind of path
exec: allow file_ram_alloc to work on file
next prev parent reply other threads:[~2015-11-09 10:54 UTC|newest]
Thread overview: 182+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-30 5:55 [PATCH v6 00/33] implement vNVDIMM Xiao Guangrong
2015-10-30 5:55 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:55 ` [PATCH v6 01/33] acpi: add aml_derefof Xiao Guangrong
2015-10-30 5:55 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:55 ` [PATCH v6 02/33] acpi: add aml_sizeof Xiao Guangrong
2015-10-30 5:55 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:55 ` [PATCH v6 03/33] acpi: add aml_create_field Xiao Guangrong
2015-10-30 5:55 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:55 ` [PATCH v6 04/33] acpi: add aml_concatenate Xiao Guangrong
2015-10-30 5:55 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:55 ` [PATCH v6 05/33] acpi: add aml_object_type Xiao Guangrong
2015-10-30 5:55 ` [Qemu-devel] " Xiao Guangrong
2015-11-09 11:35 ` Michael S. Tsirkin
2015-11-09 11:35 ` [Qemu-devel] " Michael S. Tsirkin
2015-11-09 12:40 ` Igor Mammedov
2015-11-09 12:40 ` [Qemu-devel] " Igor Mammedov
2015-10-30 5:56 ` [PATCH v6 06/33] acpi: add aml_method_serialized Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-11-09 11:14 ` Michael S. Tsirkin
2015-11-09 11:14 ` [Qemu-devel] " Michael S. Tsirkin
2015-11-09 11:18 ` Xiao Guangrong
2015-11-09 11:18 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:56 ` [PATCH v6 07/33] util: introduce qemu_file_get_page_size() Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 13:26 ` Vladimir Sementsov-Ogievskiy
2015-10-30 13:26 ` Vladimir Sementsov-Ogievskiy
2015-10-31 7:26 ` Xiao Guangrong
2015-10-31 7:26 ` [Qemu-devel] " Xiao Guangrong
2015-10-31 9:37 ` Vladimir Sementsov-Ogievskiy
2015-10-31 9:37 ` Vladimir Sementsov-Ogievskiy
2015-10-31 14:06 ` Xiao Guangrong
2015-10-31 14:06 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 15:54 ` Eduardo Habkost
2015-10-30 15:54 ` [Qemu-devel] " Eduardo Habkost
2015-10-31 8:09 ` Xiao Guangrong
2015-10-31 8:09 ` [Qemu-devel] " Xiao Guangrong
2015-10-31 14:11 ` Eduardo Habkost
2015-10-31 14:11 ` [Qemu-devel] " Eduardo Habkost
2015-10-31 17:03 ` Xiao Guangrong
2015-10-31 17:03 ` [Qemu-devel] " Xiao Guangrong
2015-11-09 20:00 ` Michael S. Tsirkin
2015-11-09 20:00 ` [Qemu-devel] " Michael S. Tsirkin
2015-10-31 8:25 ` Xiao Guangrong
2015-10-31 8:25 ` [Qemu-devel] " Xiao Guangrong
2015-11-09 10:33 ` Michael S. Tsirkin
2015-11-09 10:33 ` [Qemu-devel] " Michael S. Tsirkin
2015-11-09 10:55 ` Xiao Guangrong
2015-11-09 10:55 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:56 ` [PATCH v6 08/33] exec: allow memory to be allocated from any kind of path Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 14:04 ` Vladimir Sementsov-Ogievskiy
2015-10-30 14:04 ` Vladimir Sementsov-Ogievskiy
2015-10-31 7:44 ` Xiao Guangrong
2015-10-31 13:55 ` Eduardo Habkost
2015-10-31 13:55 ` Eduardo Habkost
2015-10-31 15:56 ` Xiao Guangrong
2015-10-31 15:56 ` Xiao Guangrong
2015-11-09 10:39 ` Michael S. Tsirkin
2015-11-09 10:39 ` [Qemu-devel] " Michael S. Tsirkin
2015-11-09 11:01 ` Xiao Guangrong
2015-11-09 11:01 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:56 ` [PATCH v6 09/33] exec: allow file_ram_alloc to work on file Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 14:25 ` Vladimir Sementsov-Ogievskiy
2015-10-30 14:25 ` Vladimir Sementsov-Ogievskiy
2015-10-31 7:53 ` Xiao Guangrong
2015-10-31 7:53 ` [Qemu-devel] " Xiao Guangrong
2015-11-09 10:13 ` Michael S. Tsirkin
2015-11-09 10:13 ` [Qemu-devel] " Michael S. Tsirkin
2015-11-09 10:48 ` Xiao Guangrong [this message]
2015-11-09 10:48 ` Xiao Guangrong
2015-10-30 5:56 ` [PATCH v6 10/33] hostmem-file: clean up memory allocation Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 14:54 ` Vladimir Sementsov-Ogievskiy
2015-10-30 14:54 ` Vladimir Sementsov-Ogievskiy
2015-10-30 5:56 ` [PATCH v6 11/33] hostmem-file: use whole file size if possible Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 15:27 ` Vladimir Sementsov-Ogievskiy
2015-10-30 15:27 ` Vladimir Sementsov-Ogievskiy
2015-10-31 7:59 ` Xiao Guangrong
2015-10-31 7:59 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 17:30 ` Eduardo Habkost
2015-10-30 17:30 ` Eduardo Habkost
2015-10-31 8:46 ` Xiao Guangrong
2015-10-31 8:46 ` Xiao Guangrong
2015-10-31 13:45 ` Eduardo Habkost
2015-10-31 13:45 ` Eduardo Habkost
2015-10-31 16:59 ` Xiao Guangrong
2015-10-31 16:59 ` [Qemu-devel] " Xiao Guangrong
2015-11-09 10:17 ` Michael S. Tsirkin
2015-11-09 10:17 ` [Qemu-devel] " Michael S. Tsirkin
2015-11-09 10:49 ` Xiao Guangrong
2015-11-09 10:49 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:56 ` [PATCH v6 12/33] pc-dimm: remove DEFAULT_PC_DIMMSIZE Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-11-09 10:40 ` Michael S. Tsirkin
2015-11-09 10:40 ` [Qemu-devel] " Michael S. Tsirkin
2015-11-09 11:03 ` Xiao Guangrong
2015-11-09 11:03 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:56 ` [PATCH v6 13/33] pc-dimm: make pc_existing_dimms_capacity static and rename it Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 15:38 ` Vladimir Sementsov-Ogievskiy
2015-10-30 15:38 ` Vladimir Sementsov-Ogievskiy
2015-10-30 5:56 ` [PATCH v6 14/33] pc-dimm: drop the prefix of pc-dimm Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 16:10 ` Vladimir Sementsov-Ogievskiy
2015-10-30 16:10 ` Vladimir Sementsov-Ogievskiy
2015-10-31 8:18 ` Xiao Guangrong
2015-10-30 17:06 ` Eric Blake
2015-10-31 8:23 ` Xiao Guangrong
2015-11-09 20:05 ` Michael S. Tsirkin
2015-11-09 20:05 ` [Qemu-devel] " Michael S. Tsirkin
2015-10-30 5:56 ` [PATCH v6 15/33] stubs: rename qmp_pc_dimm_device_list.c Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:56 ` [PATCH v6 16/33] pc-dimm: rename pc-dimm.c and pc-dimm.h Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-31 10:28 ` Vladimir Sementsov-Ogievskiy
2015-10-31 10:28 ` Vladimir Sementsov-Ogievskiy
2015-10-30 5:56 ` [PATCH v6 17/33] dimm: abstract dimm device from pc-dimm Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-31 10:41 ` Vladimir Sementsov-Ogievskiy
2015-10-31 10:41 ` [Qemu-devel] " Vladimir Sementsov-Ogievskiy
2015-10-30 5:56 ` [PATCH v6 18/33] dimm: get mapped memory region from DIMMDeviceClass->get_memory_region Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-31 10:52 ` Vladimir Sementsov-Ogievskiy
2015-10-31 10:52 ` Vladimir Sementsov-Ogievskiy
2015-10-31 14:15 ` Xiao Guangrong
2015-10-31 14:15 ` [Qemu-devel] " Xiao Guangrong
2015-11-02 9:18 ` Xiao Guangrong
2015-10-30 5:56 ` [PATCH v6 19/33] dimm: keep the state of the whole backend memory Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-31 11:05 ` Vladimir Sementsov-Ogievskiy
2015-10-31 11:05 ` Vladimir Sementsov-Ogievskiy
2015-10-31 14:19 ` Xiao Guangrong
2015-11-09 11:04 ` Michael S. Tsirkin
2015-11-09 11:04 ` [Qemu-devel] " Michael S. Tsirkin
2015-11-09 11:13 ` Xiao Guangrong
2015-11-09 11:13 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:56 ` [PATCH v6 20/33] dimm: introduce realize callback Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-31 11:22 ` Vladimir Sementsov-Ogievskiy
2015-10-31 11:22 ` [Qemu-devel] " Vladimir Sementsov-Ogievskiy
2015-10-30 5:56 ` [PATCH v6 21/33] nvdimm: implement NVDIMM device abstract Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:56 ` [PATCH v6 22/33] docs: add NVDIMM ACPI documentation Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:56 ` [PATCH v6 23/33] nvdimm acpi: init the resource used by NVDIMM ACPI Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:56 ` [PATCH v6 24/33] nvdimm acpi: build ACPI NFIT table Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:56 ` [PATCH v6 25/33] nvdimm acpi: build ACPI nvdimm devices Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-11-08 17:38 ` Michael S. Tsirkin
2015-11-08 17:38 ` [Qemu-devel] " Michael S. Tsirkin
2015-11-09 6:07 ` Xiao Guangrong
2015-11-09 6:07 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:56 ` [PATCH v6 26/33] nvdimm acpi: save arg3 for NVDIMM device _DSM method Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:56 ` [PATCH v6 27/33] nvdimm acpi: support function 0 Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 10:14 ` Stefan Hajnoczi
2015-10-30 10:14 ` [Qemu-devel] " Stefan Hajnoczi
2015-10-30 13:01 ` Xiao Guangrong
2015-10-30 13:01 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:56 ` [PATCH v6 28/33] nvdimm acpi: support Get Namespace Label Size function Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:56 ` [PATCH v6 29/33] nvdimm acpi: support Get Namespace Label Data function Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:56 ` [PATCH v6 30/33] nvdimm acpi: support Set " Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:56 ` [PATCH v6 31/33] nvdimm: allow using whole backend memory as pmem Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:56 ` [PATCH v6 32/33] nvdimm acpi: support _FIT method Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-11-08 17:50 ` Michael S. Tsirkin
2015-11-08 17:50 ` [Qemu-devel] " Michael S. Tsirkin
2015-11-09 6:37 ` Xiao Guangrong
2015-11-09 6:37 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 5:56 ` [PATCH v6 33/33] nvdimm: add maintain info Xiao Guangrong
2015-10-30 5:56 ` [Qemu-devel] " Xiao Guangrong
2015-10-30 10:15 ` [PATCH v6 00/33] implement vNVDIMM Stefan Hajnoczi
2015-10-30 10:15 ` [Qemu-devel] " Stefan Hajnoczi
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=564079EC.6010804@linux.intel.com \
--to=guangrong.xiao@linux.intel.com \
--cc=dan.j.williams@intel.com \
--cc=ehabkost@redhat.com \
--cc=gleb@kernel.org \
--cc=imammedo@redhat.com \
--cc=kvm@vger.kernel.org \
--cc=mst@redhat.com \
--cc=mtosatti@redhat.com \
--cc=pbonzini@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=rth@twiddle.net \
--cc=stefanha@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.