Re: [Qemu-devel] [PATCH v6 08/33] exec: allow memory to be allocated from any kind of path

[Eduardo Habkost]

On Sat, Oct 31, 2015 at 03:44:39PM +0800, Xiao Guangrong wrote:
> On 10/30/2015 10:04 PM, Vladimir Sementsov-Ogievskiy wrote:
> >On 30.10.2015 08:56, Xiao Guangrong wrote:
> >>Currently file_ram_alloc() is designed for hugetlbfs, however, the memory
> >>of nvdimm can come from either raw pmem device eg, /dev/pmem, or the file
> >>locates at DAX enabled filesystem
> >>
> >>So this patch let it work on any kind of path
> >>
> >>Signed-off-by: Xiao Guangrong <address@hidden>
[...]
> >>-    block->mr->align = hpagesize;
> >>-    if (memory < hpagesize) {
> >>+    if (pagesize == getpagesize()) {
> >>+        fprintf(stderr, "Memory is not allocated from HugeTlbfs.\n");
> >>+    }
> >
> >It is strange to see this warning every time.
> >
> >Shouldn't the differentiation be done explicitly in command line? May be 
> >separate option mem-tlb, or
> >separate flag tlbfs=on, or for new feature - new option mem-file, or 
> >prefixes for paths (tlbfs://,
> >file://).. Or the other way to not mix things but split them.
> 
> This is just a reminder to users. Currently Qemu do not stop user to append a 
> regular file
> for its backend memory, particularly, hugetlbfs is not the only way to use 
> HugePage for
> the THP-enabled system.
> 
> We can implement your idea as a independent patchset in the future.

Isn't the whole point of this patch to make the code not specific to
hugetlbfs anymore? It makes the warning obsolete.

-- 
Eduardo