Re: [libvirt] [PATCH 5/5] qemuBuildMemoryBackendProps: Get pagesize early
On 4/2/19 2:57 PM, Ján Tomko wrote:
On Mon, Apr 01, 2019 at 04:04:37PM +0200, Michal Privoznik wrote:
> https://bugzilla.redhat.com/show_bug.cgi?id=1693066
>
> Up until memfd introduction (in 24b74d187ca) we did not need to
> know @pagesize because qemuGetDomainHupageMemPath() could deal
> with it being zero (value of zero means use the default hugetlbfs
> mount). But since for memfd we are not passing a path to
> hugetlbfs mount rather the page size value we need to know its
> value upfront.
This phrasing makes it seem like getting the pagesize is being moved,
>
> Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
> ---
> src/qemu/qemu_command.c | 14 +++++++
> ...memory-default-hugepage.x86_64-latest.args | 37 ++++++++++++++++
> .../memfd-memory-default-hugepage.xml | 42 +++++++++++++++++++
> tests/qemuxml2argvtest.c | 1 +
> .../memfd-memory-default-hugepage.xml | 1 +
> tests/qemuxml2xmltest.c | 3 ++
> 6 files changed, 98 insertions(+)
but there are no deletions. I'd expect that now it will no longer be
needed in qemuGetDomainHupageMemPath (sic).
In fact, it is. See below.
> create mode 100644
> tests/qemuxml2argvdata/memfd-memory-default-hugepage.x86_64-latest.args
> create mode 100644
> tests/qemuxml2argvdata/memfd-memory-default-hugepage.xml
> create mode 120000
> tests/qemuxml2xmloutdata/memfd-memory-default-hugepage.xml
>
> diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
> index f81d20e5f7..ba1b56c2da 100644
> --- a/src/qemu/qemu_command.c
> +++ b/src/qemu/qemu_command.c
> @@ -3547,6 +3547,20 @@ qemuBuildMemoryBackendProps(virJSONValuePtr
> *backendProps,
> pagesize = 0;
> needHugepage = false;
> useHugepage = false;
> + } else if (pagesize == 0) {
> + virHugeTLBFSPtr p;
> +
> + if (!cfg->nhugetlbfs) {
> + virReportError(VIR_ERR_INTERNAL_ERROR,
> + "%s", _("hugetlbfs filesystem is not
> mounted "
> + "or disabled by administrator
> config"));
> + goto cleanup;
> + }
> +
> + if (!(p = virFileGetDefaultHugepage(cfg->hugetlbfs,
> cfg->nhugetlbfs)))
> + p = &cfg->hugetlbfs[0];
> +
> + pagesize = p->size;
Given how big and beautiful qemuBuildMemoryBackendProps has become,
this would look nicer in another wrapper.
Okay.
With the corresponding deletions in qemuGetDomainHupageMemPath:
qemuGetDomainHupageMemPath is called when building -mem-path too
(qemuBuildMemPathStr). And that's the place where pagesize can be 0 too.
Reviewed-by: Ján Tomko <jtomko(a)redhat.com>
Thanks.
Michal