[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PATCH V4 04/10] xen: introduce mark_page_free

Hi Penny,

On 28/07/2021 11:27, Penny Zheng wrote:
This commit defines a new helper mark_page_free to extract common code,
like following the same cache/TLB coherency policy, between free_heap_pages
and the new function free_staticmem_pages, which will be introduced later.

Signed-off-by: Penny Zheng <penny.zheng@xxxxxxx>
Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
  xen/common/page_alloc.c | 89 ++++++++++++++++++++++-------------------
  1 file changed, 48 insertions(+), 41 deletions(-)

diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
index 958ba0cd92..a3ee5eca9e 100644
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -1376,6 +1376,53 @@ bool scrub_free_pages(void)
      return node_to_scrub(false) != NUMA_NO_NODE;
+static void mark_page_free(struct page_info *pg, mfn_t mfn)
+    ASSERT(mfn_x(mfn) == mfn_x(page_to_mfn(pg)));

NIT: If I got it correctly, the assumption is page_to_mfn() is expensive, so we want to avoid the conversation. I am not sure I agree with that but I would at least suggest to write it down in the commit message.

So it is easier for the next person to figure out the rationale. Something like:

"The PDX compression makes makes conversion between the MFN and the page can be potentially non-trivial. As the function is internal, pass the MFN and the page. They are both expected to match."

For the rest of the patch:

Reviewed-by: Julien Grall <jgrall@xxxxxxxxxx>


Julien Grall



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.