moonjuice/kernel_arpi
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

mm/rmap: split migration into its own function

Browse Source 
Migration is currently implemented as a mode of operation for
try_to_unmap_one() generally specified by passing the TTU_MIGRATION flag
or in the case of splitting a huge anonymous page TTU_SPLIT_FREEZE.

However it does not have much in common with the rest of the unmap
functionality of try_to_unmap_one() and thus splitting it into a separate
function reduces the complexity of try_to_unmap_one() making it more
readable.

Several simplifications can also be made in try_to_migrate_one() based on
the following observations:

 - All users of TTU_MIGRATION also set TTU_IGNORE_MLOCK.
 - No users of TTU_MIGRATION ever set TTU_IGNORE_HWPOISON.
 - No users of TTU_MIGRATION ever set TTU_BATCH_FLUSH.

TTU_SPLIT_FREEZE is a special case of migration used when splitting an
anonymous page.  This is most easily dealt with by calling the correct
function from unmap_page() in mm/huge_memory.c - either try_to_migrate()
for PageAnon or try_to_unmap().

Link: https://lkml.kernel.org/r/20210616105937.23201-5-apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alistair Popple
2021-06-30 18:54:16 -07:00
committed by Linus Torvalds
parent cd62734ca6
commit a98a2f0c8c
4 changed files with 289 additions and 107 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
mm/migrate.c
View File

@@ -1109,7 +1109,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
/* Establish migration ptes */
VM_BUG_ON_PAGE(PageAnon(page) && !PageKsm(page) && !anon_vma,
page);
try_to_unmap(page, TTU_MIGRATION|TTU_IGNORE_MLOCK);
try_to_migrate(page, 0);
page_was_mapped = 1;
}
@@ -1311,7 +1311,7 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
if (page_mapped(hpage)) {
bool mapping_locked = false;
enum ttu_flags ttu = TTU_MIGRATION|TTU_IGNORE_MLOCK;
enum ttu_flags ttu = 0;
if (!PageAnon(hpage)) {
/*
@@ -1328,7 +1328,7 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
ttu |= TTU_RMAP_LOCKED;
}
try_to_unmap(hpage, ttu);
try_to_migrate(hpage, ttu);
page_was_mapped = 1;
if (mapping_locked)
@@ -2602,7 +2602,6 @@ static void migrate_vma_prepare(struct migrate_vma *migrate)
*/
static void migrate_vma_unmap(struct migrate_vma *migrate)
{
int flags = TTU_MIGRATION | TTU_IGNORE_MLOCK;
const unsigned long npages = migrate->npages;
const unsigned long start = migrate->start;
unsigned long addr, i, restore = 0;
@@ -2614,7 +2613,7 @@ static void migrate_vma_unmap(struct migrate_vma *migrate)
continue;
if (page_mapped(page)) {
try_to_unmap(page, flags);
try_to_migrate(page, 0);
if (page_mapped(page))
goto restore;
}