The patch titled
Subject: mm/migrate: optimize migrate_vma_setup() for holes
has been added to the -mm tree. Its filename is
mm-migrate-optimize-migrate_vma_setup-for-holes.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-migrate-optimize-migrate_vma_setup-for-holes.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-migrate-optimize-migrate_vma_setup-for-holes.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Ralph Campbell <rcampbell@xxxxxxxxxx>
Subject: mm/migrate: optimize migrate_vma_setup() for holes
Patch series "mm/migrate: optimize migrate_vma_setup() for holes".
A simple optimization for migrate_vma_*() when the source vma is not an
anonymous vma and a new test case to exercise it.
This patch (of 2):
When migrating system memory to device private memory, if the source
address range is a valid VMA range and there is no memory or a zero page,
the source PFN array is marked as valid but with no PFN.
This lets the device driver allocate private memory and clear it, then
insert the new device private struct page into the CPU's page tables when
migrate_vma_pages() is called. migrate_vma_pages() only inserts the new
page if the VMA is an anonymous range.
There is no point in telling the device driver to allocate device private
memory and then not migrate the page. Instead, mark the source PFN array
entries as not migrating to avoid this overhead.
Link: http://lkml.kernel.org/r/20200709165711.26584-1-rcampbell@xxxxxxxxxx
Link: http://lkml.kernel.org/r/20200709165711.26584-2-rcampbell@xxxxxxxxxx
Signed-off-by: Ralph Campbell <rcampbell@xxxxxxxxxx>
Cc: Jerome Glisse <jglisse@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Cc: "Bharata B Rao" <bharata@xxxxxxxxxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/migrate.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--- a/mm/migrate.c~mm-migrate-optimize-migrate_vma_setup-for-holes
+++ a/mm/migrate.c
@@ -2167,9 +2167,13 @@ static int migrate_vma_collect_hole(unsi
{
struct migrate_vma *migrate = walk->private;
unsigned long addr;
+ unsigned long flags;
+
+ /* Only allow populating anonymous memory. */
+ flags = vma_is_anonymous(walk->vma) ? MIGRATE_PFN_MIGRATE : 0;
for (addr = start; addr < end; addr += PAGE_SIZE) {
- migrate->src[migrate->npages] = MIGRATE_PFN_MIGRATE;
+ migrate->src[migrate->npages] = flags;
migrate->dst[migrate->npages] = 0;
migrate->npages++;
migrate->cpages++;
_
Patches currently in -mm which might be from rcampbell@xxxxxxxxxx are
mm-remove-redundant-check-non_swap_entry.patch
mm-migrate-optimize-migrate_vma_setup-for-holes.patch
mm-migrate-add-migrate-shared-test-for-migrate_vma_.patch
