| Message ID | 20221227002859.27740-5-ying.huang@intel.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | migrate_pages(): batch TLB flushing | expand |
On 26 Dec 2022, at 19:28, Huang Ying wrote: > This is a preparation patch to batch the folio unmapping and moving. > > In this patch, unmap_and_move() is split to migrate_folio_unmap() and > migrate_folio_move(). So, we can batch _unmap() and _move() in > different loops later. To pass some information between unmap and > move, the original unused dst->mapping and dst->private are used. > > Signed-off-by: "Huang, Ying" <ying.huang@intel.com> > Cc: Zi Yan <ziy@nvidia.com> > Cc: Yang Shi <shy828301@gmail.com> > Cc: Baolin Wang <baolin.wang@linux.alibaba.com> > Cc: Oscar Salvador <osalvador@suse.de> > Cc: Matthew Wilcox <willy@infradead.org> > Cc: Bharata B Rao <bharata@amd.com> > Cc: Alistair Popple <apopple@nvidia.com> > Cc: haoxin <xhao@linux.alibaba.com> > --- > include/linux/migrate.h | 1 + > mm/migrate.c | 162 +++++++++++++++++++++++++++++----------- > 2 files changed, 121 insertions(+), 42 deletions(-) > > diff --git a/include/linux/migrate.h b/include/linux/migrate.h > index 3ef77f52a4f0..7376074f2e1e 100644 > --- a/include/linux/migrate.h > +++ b/include/linux/migrate.h > @@ -18,6 +18,7 @@ struct migration_target_control; > * - zero on page migration success; > */ > #define MIGRATEPAGE_SUCCESS 0 > +#define MIGRATEPAGE_UNMAP 1 > > /** > * struct movable_operations - Driver page migration > diff --git a/mm/migrate.c b/mm/migrate.c > index 97ea0737ab2b..e2383b430932 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -1009,11 +1009,29 @@ static int move_to_new_folio(struct folio *dst, struct folio *src, > return rc; > } > > -static int __unmap_and_move(struct folio *src, struct folio *dst, > +static void __migrate_folio_record(struct folio *dst, > + unsigned long page_was_mapped, > + struct anon_vma *anon_vma) > +{ > + dst->mapping = (struct address_space *)anon_vma; > + dst->private = (void *)page_was_mapped; > +} > + > +static void __migrate_folio_extract(struct folio *dst, > + int *page_was_mappedp, > + struct anon_vma **anon_vmap) > +{ > + *anon_vmap = (struct anon_vma *)dst->mapping; > + *page_was_mappedp = (unsigned long)dst->private; > + dst->mapping = NULL; > + dst->private = NULL; > +} > + We probably need comments on these two functions on using dst->mapping and dst->private. It might be hard to get the behavior later by digging into the git log and/or looking at the code. > +static int __migrate_folio_unmap(struct folio *src, struct folio *dst, > int force, enum migrate_mode mode) > { > int rc = -EAGAIN; > - bool page_was_mapped = false; > + int page_was_mapped = 0; > struct anon_vma *anon_vma = NULL; > bool is_lru = !__PageMovable(&src->page); > > @@ -1089,8 +1107,8 @@ static int __unmap_and_move(struct folio *src, struct folio *dst, > goto out_unlock; > > if (unlikely(!is_lru)) { > - rc = move_to_new_folio(dst, src, mode); > - goto out_unlock_both; > + __migrate_folio_record(dst, page_was_mapped, anon_vma); > + return MIGRATEPAGE_UNMAP; > } > > /* > @@ -1115,11 +1133,40 @@ static int __unmap_and_move(struct folio *src, struct folio *dst, > VM_BUG_ON_FOLIO(folio_test_anon(src) && > !folio_test_ksm(src) && !anon_vma, src); > try_to_migrate(src, 0); > - page_was_mapped = true; > + page_was_mapped = 1; > } > > - if (!folio_mapped(src)) > - rc = move_to_new_folio(dst, src, mode); > + if (!folio_mapped(src)) { > + __migrate_folio_record(dst, page_was_mapped, anon_vma); > + return MIGRATEPAGE_UNMAP; > + } > + > + > + if (page_was_mapped) > + remove_migration_ptes(src, src, false); > + > +out_unlock_both: > + folio_unlock(dst); > +out_unlock: > + /* Drop an anon_vma reference if we took one */ > + if (anon_vma) > + put_anon_vma(anon_vma); > + folio_unlock(src); > +out: > + > + return rc; > +} > + > +static int __migrate_folio_move(struct folio *src, struct folio *dst, > + enum migrate_mode mode) > +{ > + int rc; > + int page_was_mapped = 0; > + struct anon_vma *anon_vma = NULL; > + > + __migrate_folio_extract(dst, &page_was_mapped, &anon_vma); > + > + rc = move_to_new_folio(dst, src, mode); > > /* > * When successful, push dst to LRU immediately: so that if it > @@ -1140,14 +1187,11 @@ static int __unmap_and_move(struct folio *src, struct folio *dst, > remove_migration_ptes(src, > rc == MIGRATEPAGE_SUCCESS ? dst : src, false); > > -out_unlock_both: > folio_unlock(dst); > -out_unlock: > /* Drop an anon_vma reference if we took one */ > if (anon_vma) > put_anon_vma(anon_vma); > folio_unlock(src); > -out: > /* > * If migration is successful, decrease refcount of dst, > * which will not free the page because new page owner increased > @@ -1159,19 +1203,32 @@ static int __unmap_and_move(struct folio *src, struct folio *dst, > return rc; > } > > -/* > - * Obtain the lock on folio, remove all ptes and migrate the folio > - * to the newly allocated folio in dst. > - */ > -static int unmap_and_move(new_page_t get_new_page, > - free_page_t put_new_page, > - unsigned long private, struct folio *src, > - int force, enum migrate_mode mode, > - enum migrate_reason reason, > - struct list_head *ret) > +static void migrate_folio_done(struct folio *src, > + enum migrate_reason reason) > +{ > + /* > + * Compaction can migrate also non-LRU pages which are > + * not accounted to NR_ISOLATED_*. They can be recognized > + * as __PageMovable > + */ > + if (likely(!__folio_test_movable(src))) > + mod_node_page_state(folio_pgdat(src), NR_ISOLATED_ANON + > + folio_is_file_lru(src), -folio_nr_pages(src)); > + > + if (reason != MR_MEMORY_FAILURE) > + /* We release the page in page_handle_poison. */ > + folio_put(src); > +} > + > +/* Obtain the lock on page, remove all ptes. */ > +static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page, > + unsigned long private, struct folio *src, > + struct folio **dstp, int force, > + enum migrate_mode mode, enum migrate_reason reason, > + struct list_head *ret) > { > struct folio *dst; > - int rc = MIGRATEPAGE_SUCCESS; > + int rc = MIGRATEPAGE_UNMAP; > struct page *newpage = NULL; > > if (!thp_migration_supported() && folio_test_transhuge(src)) > @@ -1182,20 +1239,50 @@ static int unmap_and_move(new_page_t get_new_page, > folio_clear_active(src); > folio_clear_unevictable(src); > /* free_pages_prepare() will clear PG_isolated. */ > - goto out; > + list_del(&src->lru); > + migrate_folio_done(src, reason); > + return MIGRATEPAGE_SUCCESS; > } > > newpage = get_new_page(&src->page, private); > if (!newpage) > return -ENOMEM; > dst = page_folio(newpage); > + *dstp = dst; > > dst->private = NULL; > - rc = __unmap_and_move(src, dst, force, mode); > + rc = __migrate_folio_unmap(src, dst, force, mode); > + if (rc == MIGRATEPAGE_UNMAP) > + return rc; > + > + /* > + * A page that has not been migrated will have kept its > + * references and be restored. > + */ > + /* restore the folio to right list. */ > + if (rc != -EAGAIN) > + list_move_tail(&src->lru, ret); > + > + if (put_new_page) > + put_new_page(&dst->page, private); > + else > + folio_put(dst); > + > + return rc; > +} > + > +/* Migrate the folio to the newly allocated folio in dst. */ > +static int migrate_folio_move(free_page_t put_new_page, unsigned long private, > + struct folio *src, struct folio *dst, > + enum migrate_mode mode, enum migrate_reason reason, > + struct list_head *ret) > +{ > + int rc; > + > + rc = __migrate_folio_move(src, dst, mode); > if (rc == MIGRATEPAGE_SUCCESS) > set_page_owner_migrate_reason(&dst->page, reason); > > -out: > if (rc != -EAGAIN) { > /* > * A folio that has been migrated has all references > @@ -1211,20 +1298,7 @@ static int unmap_and_move(new_page_t get_new_page, > * we want to retry. > */ > if (rc == MIGRATEPAGE_SUCCESS) { > - /* > - * Compaction can migrate also non-LRU folios which are > - * not accounted to NR_ISOLATED_*. They can be recognized > - * as __folio_test_movable > - */ > - if (likely(!__folio_test_movable(src))) > - mod_node_page_state(folio_pgdat(src), NR_ISOLATED_ANON + > - folio_is_file_lru(src), -folio_nr_pages(src)); > - > - if (reason != MR_MEMORY_FAILURE) > - /* > - * We release the folio in page_handle_poison. > - */ > - folio_put(src); > + migrate_folio_done(src, reason); > } else { > if (rc != -EAGAIN) > list_add_tail(&src->lru, ret); > @@ -1499,7 +1573,7 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, > int pass = 0; > bool is_large = false; > bool is_thp = false; > - struct folio *folio, *folio2; > + struct folio *folio, *folio2, *dst = NULL; > int rc, nr_pages; > LIST_HEAD(split_folios); > bool nosplit = (reason == MR_NUMA_MISPLACED); > @@ -1524,9 +1598,13 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, > > cond_resched(); > > - rc = unmap_and_move(get_new_page, put_new_page, > - private, folio, pass > 2, mode, > - reason, ret_folios); > + rc = migrate_folio_unmap(get_new_page, put_new_page, private, > + folio, &dst, pass > 2, mode, > + reason, ret_folios); > + if (rc == MIGRATEPAGE_UNMAP) > + rc = migrate_folio_move(put_new_page, private, > + folio, dst, mode, > + reason, ret_folios); > /* > * The rules are: > * Success: folio will be freed > -- > 2.35.1 -- Best Regards, Yan, Zi
Hi Ying, On Tue, Dec 27, 2022 at 08:28:55AM +0800, Huang Ying wrote: > This is a preparation patch to batch the folio unmapping and moving. > > In this patch, unmap_and_move() is split to migrate_folio_unmap() and > migrate_folio_move(). So, we can batch _unmap() and _move() in > different loops later. To pass some information between unmap and > move, the original unused dst->mapping and dst->private are used. > > Signed-off-by: "Huang, Ying" <ying.huang@intel.com> > Cc: Zi Yan <ziy@nvidia.com> > Cc: Yang Shi <shy828301@gmail.com> > Cc: Baolin Wang <baolin.wang@linux.alibaba.com> > Cc: Oscar Salvador <osalvador@suse.de> > Cc: Matthew Wilcox <willy@infradead.org> > Cc: Bharata B Rao <bharata@amd.com> > Cc: Alistair Popple <apopple@nvidia.com> > Cc: haoxin <xhao@linux.alibaba.com> > --- > include/linux/migrate.h | 1 + > mm/migrate.c | 162 +++++++++++++++++++++++++++++----------- > 2 files changed, 121 insertions(+), 42 deletions(-) > > diff --git a/include/linux/migrate.h b/include/linux/migrate.h > index 3ef77f52a4f0..7376074f2e1e 100644 > --- a/include/linux/migrate.h > +++ b/include/linux/migrate.h > @@ -18,6 +18,7 @@ struct migration_target_control; > * - zero on page migration success; > */ > #define MIGRATEPAGE_SUCCESS 0 > +#define MIGRATEPAGE_UNMAP 1 > > /** > * struct movable_operations - Driver page migration > diff --git a/mm/migrate.c b/mm/migrate.c > index 97ea0737ab2b..e2383b430932 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -1009,11 +1009,29 @@ static int move_to_new_folio(struct folio *dst, struct folio *src, > return rc; > } > > -static int __unmap_and_move(struct folio *src, struct folio *dst, > +static void __migrate_folio_record(struct folio *dst, > + unsigned long page_was_mapped, > + struct anon_vma *anon_vma) > +{ > + dst->mapping = (struct address_space *)anon_vma; > + dst->private = (void *)page_was_mapped; > +} > + > +static void __migrate_folio_extract(struct folio *dst, > + int *page_was_mappedp, > + struct anon_vma **anon_vmap) > +{ > + *anon_vmap = (struct anon_vma *)dst->mapping; > + *page_was_mappedp = (unsigned long)dst->private; > + dst->mapping = NULL; > + dst->private = NULL; > +} This patch as commit 42871c600cad ("migrate_pages: split unmap_and_move() to _unmap() and _move()") in next-20230105 causes the following error with clang when CONFIG_RANDSTRUCT is enabled, which is the case with allmodconfig: ../mm/migrate.c:1041:15: error: casting from randomized structure pointer type 'struct address_space *' to 'struct anon_vma *' *anon_vmap = (struct anon_vma *)dst->mapping; ^ 1 error generated. With GCC, there is only a note: ../mm/migrate.c: In function '__migrate_folio_extract': ../mm/migrate.c:1041:20: note: randstruct: casting between randomized structure pointer types (ssa): 'struct anon_vma' and 'struct address_space' 1041 | *anon_vmap = (struct anon_vma *)dst->mapping; | ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Kees has done fixes for warnings and errors like this in the past (I just ran $ git log -p --grep='randomized structure pointer type' to find them) but I did not see any that would seem appropriate here hence just the report :) Cheers, Nathan
On Thu, Jan 05, 2023 at 11:26:55AM -0700, Nathan Chancellor wrote: > Hi Ying, > > On Tue, Dec 27, 2022 at 08:28:55AM +0800, Huang Ying wrote: > > This is a preparation patch to batch the folio unmapping and moving. > > > > In this patch, unmap_and_move() is split to migrate_folio_unmap() and > > migrate_folio_move(). So, we can batch _unmap() and _move() in > > different loops later. To pass some information between unmap and > > move, the original unused dst->mapping and dst->private are used. > > > > Signed-off-by: "Huang, Ying" <ying.huang@intel.com> > > Cc: Zi Yan <ziy@nvidia.com> > > Cc: Yang Shi <shy828301@gmail.com> > > Cc: Baolin Wang <baolin.wang@linux.alibaba.com> > > Cc: Oscar Salvador <osalvador@suse.de> > > Cc: Matthew Wilcox <willy@infradead.org> > > Cc: Bharata B Rao <bharata@amd.com> > > Cc: Alistair Popple <apopple@nvidia.com> > > Cc: haoxin <xhao@linux.alibaba.com> > > --- > > include/linux/migrate.h | 1 + > > mm/migrate.c | 162 +++++++++++++++++++++++++++++----------- > > 2 files changed, 121 insertions(+), 42 deletions(-) > > > > diff --git a/include/linux/migrate.h b/include/linux/migrate.h > > index 3ef77f52a4f0..7376074f2e1e 100644 > > --- a/include/linux/migrate.h > > +++ b/include/linux/migrate.h > > @@ -18,6 +18,7 @@ struct migration_target_control; > > * - zero on page migration success; > > */ > > #define MIGRATEPAGE_SUCCESS 0 > > +#define MIGRATEPAGE_UNMAP 1 > > > > /** > > * struct movable_operations - Driver page migration > > diff --git a/mm/migrate.c b/mm/migrate.c > > index 97ea0737ab2b..e2383b430932 100644 > > --- a/mm/migrate.c > > +++ b/mm/migrate.c > > @@ -1009,11 +1009,29 @@ static int move_to_new_folio(struct folio *dst, struct folio *src, > > return rc; > > } > > > > -static int __unmap_and_move(struct folio *src, struct folio *dst, > > +static void __migrate_folio_record(struct folio *dst, > > + unsigned long page_was_mapped, > > + struct anon_vma *anon_vma) > > +{ > > + dst->mapping = (struct address_space *)anon_vma; > > + dst->private = (void *)page_was_mapped; > > +} > > + > > +static void __migrate_folio_extract(struct folio *dst, > > + int *page_was_mappedp, > > + struct anon_vma **anon_vmap) > > +{ > > + *anon_vmap = (struct anon_vma *)dst->mapping; > > + *page_was_mappedp = (unsigned long)dst->private; > > + dst->mapping = NULL; > > + dst->private = NULL; > > +} > > This patch as commit 42871c600cad ("migrate_pages: split > unmap_and_move() to _unmap() and _move()") in next-20230105 causes the > following error with clang when CONFIG_RANDSTRUCT is enabled, which is > the case with allmodconfig: > > ../mm/migrate.c:1041:15: error: casting from randomized structure pointer type 'struct address_space *' to 'struct anon_vma *' > *anon_vmap = (struct anon_vma *)dst->mapping; > ^ > 1 error generated. > > With GCC, there is only a note: > > ../mm/migrate.c: In function '__migrate_folio_extract': > ../mm/migrate.c:1041:20: note: randstruct: casting between randomized structure pointer types (ssa): 'struct anon_vma' and 'struct address_space' > > 1041 | *anon_vmap = (struct anon_vma *)dst->mapping; > | ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > Kees has done fixes for warnings and errors like this in the past (I > just ran > > $ git log -p --grep='randomized structure pointer type' > > to find them) but I did not see any that would seem appropriate here > hence just the report :) If this struct is literally just a scratch space and the original struct layout doesn't matter, it may be possible to silence this cast by using "(void *)" instead of the explicit struct type pointer.
Kees Cook <keescook@chromium.org> writes: > On Thu, Jan 05, 2023 at 11:26:55AM -0700, Nathan Chancellor wrote: >> Hi Ying, >> >> On Tue, Dec 27, 2022 at 08:28:55AM +0800, Huang Ying wrote: >> > This is a preparation patch to batch the folio unmapping and moving. >> > >> > In this patch, unmap_and_move() is split to migrate_folio_unmap() and >> > migrate_folio_move(). So, we can batch _unmap() and _move() in >> > different loops later. To pass some information between unmap and >> > move, the original unused dst->mapping and dst->private are used. >> > >> > Signed-off-by: "Huang, Ying" <ying.huang@intel.com> >> > Cc: Zi Yan <ziy@nvidia.com> >> > Cc: Yang Shi <shy828301@gmail.com> >> > Cc: Baolin Wang <baolin.wang@linux.alibaba.com> >> > Cc: Oscar Salvador <osalvador@suse.de> >> > Cc: Matthew Wilcox <willy@infradead.org> >> > Cc: Bharata B Rao <bharata@amd.com> >> > Cc: Alistair Popple <apopple@nvidia.com> >> > Cc: haoxin <xhao@linux.alibaba.com> >> > --- >> > include/linux/migrate.h | 1 + >> > mm/migrate.c | 162 +++++++++++++++++++++++++++++----------- >> > 2 files changed, 121 insertions(+), 42 deletions(-) >> > >> > diff --git a/include/linux/migrate.h b/include/linux/migrate.h >> > index 3ef77f52a4f0..7376074f2e1e 100644 >> > --- a/include/linux/migrate.h >> > +++ b/include/linux/migrate.h >> > @@ -18,6 +18,7 @@ struct migration_target_control; >> > * - zero on page migration success; >> > */ >> > #define MIGRATEPAGE_SUCCESS 0 >> > +#define MIGRATEPAGE_UNMAP 1 >> > >> > /** >> > * struct movable_operations - Driver page migration >> > diff --git a/mm/migrate.c b/mm/migrate.c >> > index 97ea0737ab2b..e2383b430932 100644 >> > --- a/mm/migrate.c >> > +++ b/mm/migrate.c >> > @@ -1009,11 +1009,29 @@ static int move_to_new_folio(struct folio *dst, struct folio *src, >> > return rc; >> > } >> > >> > -static int __unmap_and_move(struct folio *src, struct folio *dst, >> > +static void __migrate_folio_record(struct folio *dst, >> > + unsigned long page_was_mapped, >> > + struct anon_vma *anon_vma) >> > +{ >> > + dst->mapping = (struct address_space *)anon_vma; >> > + dst->private = (void *)page_was_mapped; >> > +} >> > + >> > +static void __migrate_folio_extract(struct folio *dst, >> > + int *page_was_mappedp, >> > + struct anon_vma **anon_vmap) >> > +{ >> > + *anon_vmap = (struct anon_vma *)dst->mapping; >> > + *page_was_mappedp = (unsigned long)dst->private; >> > + dst->mapping = NULL; >> > + dst->private = NULL; >> > +} >> >> This patch as commit 42871c600cad ("migrate_pages: split >> unmap_and_move() to _unmap() and _move()") in next-20230105 causes the >> following error with clang when CONFIG_RANDSTRUCT is enabled, which is >> the case with allmodconfig: >> >> ../mm/migrate.c:1041:15: error: casting from randomized structure pointer type 'struct address_space *' to 'struct anon_vma *' >> *anon_vmap = (struct anon_vma *)dst->mapping; >> ^ >> 1 error generated. >> >> With GCC, there is only a note: >> >> ../mm/migrate.c: In function '__migrate_folio_extract': >> ../mm/migrate.c:1041:20: note: randstruct: casting between randomized structure pointer types (ssa): 'struct anon_vma' and 'struct address_space' >> >> 1041 | *anon_vmap = (struct anon_vma *)dst->mapping; >> | ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >> >> Kees has done fixes for warnings and errors like this in the past (I >> just ran >> >> $ git log -p --grep='randomized structure pointer type' >> >> to find them) but I did not see any that would seem appropriate here >> hence just the report :) > > If this struct is literally just a scratch space and the original struct > layout doesn't matter, it may be possible to silence this cast by using > "(void *)" instead of the explicit struct type pointer. It works! Thank you very much! Best Regards, Huang, Ying
diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 3ef77f52a4f0..7376074f2e1e 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -18,6 +18,7 @@ struct migration_target_control; * - zero on page migration success; */ #define MIGRATEPAGE_SUCCESS 0 +#define MIGRATEPAGE_UNMAP 1 /** * struct movable_operations - Driver page migration diff --git a/mm/migrate.c b/mm/migrate.c index 97ea0737ab2b..e2383b430932 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1009,11 +1009,29 @@ static int move_to_new_folio(struct folio *dst, struct folio *src, return rc; } -static int __unmap_and_move(struct folio *src, struct folio *dst, +static void __migrate_folio_record(struct folio *dst, + unsigned long page_was_mapped, + struct anon_vma *anon_vma) +{ + dst->mapping = (struct address_space *)anon_vma; + dst->private = (void *)page_was_mapped; +} + +static void __migrate_folio_extract(struct folio *dst, + int *page_was_mappedp, + struct anon_vma **anon_vmap) +{ + *anon_vmap = (struct anon_vma *)dst->mapping; + *page_was_mappedp = (unsigned long)dst->private; + dst->mapping = NULL; + dst->private = NULL; +} + +static int __migrate_folio_unmap(struct folio *src, struct folio *dst, int force, enum migrate_mode mode) { int rc = -EAGAIN; - bool page_was_mapped = false; + int page_was_mapped = 0; struct anon_vma *anon_vma = NULL; bool is_lru = !__PageMovable(&src->page); @@ -1089,8 +1107,8 @@ static int __unmap_and_move(struct folio *src, struct folio *dst, goto out_unlock; if (unlikely(!is_lru)) { - rc = move_to_new_folio(dst, src, mode); - goto out_unlock_both; + __migrate_folio_record(dst, page_was_mapped, anon_vma); + return MIGRATEPAGE_UNMAP; } /* @@ -1115,11 +1133,40 @@ static int __unmap_and_move(struct folio *src, struct folio *dst, VM_BUG_ON_FOLIO(folio_test_anon(src) && !folio_test_ksm(src) && !anon_vma, src); try_to_migrate(src, 0); - page_was_mapped = true; + page_was_mapped = 1; } - if (!folio_mapped(src)) - rc = move_to_new_folio(dst, src, mode); + if (!folio_mapped(src)) { + __migrate_folio_record(dst, page_was_mapped, anon_vma); + return MIGRATEPAGE_UNMAP; + } + + + if (page_was_mapped) + remove_migration_ptes(src, src, false); + +out_unlock_both: + folio_unlock(dst); +out_unlock: + /* Drop an anon_vma reference if we took one */ + if (anon_vma) + put_anon_vma(anon_vma); + folio_unlock(src); +out: + + return rc; +} + +static int __migrate_folio_move(struct folio *src, struct folio *dst, + enum migrate_mode mode) +{ + int rc; + int page_was_mapped = 0; + struct anon_vma *anon_vma = NULL; + + __migrate_folio_extract(dst, &page_was_mapped, &anon_vma); + + rc = move_to_new_folio(dst, src, mode); /* * When successful, push dst to LRU immediately: so that if it @@ -1140,14 +1187,11 @@ static int __unmap_and_move(struct folio *src, struct folio *dst, remove_migration_ptes(src, rc == MIGRATEPAGE_SUCCESS ? dst : src, false); -out_unlock_both: folio_unlock(dst); -out_unlock: /* Drop an anon_vma reference if we took one */ if (anon_vma) put_anon_vma(anon_vma); folio_unlock(src); -out: /* * If migration is successful, decrease refcount of dst, * which will not free the page because new page owner increased @@ -1159,19 +1203,32 @@ static int __unmap_and_move(struct folio *src, struct folio *dst, return rc; } -/* - * Obtain the lock on folio, remove all ptes and migrate the folio - * to the newly allocated folio in dst. - */ -static int unmap_and_move(new_page_t get_new_page, - free_page_t put_new_page, - unsigned long private, struct folio *src, - int force, enum migrate_mode mode, - enum migrate_reason reason, - struct list_head *ret) +static void migrate_folio_done(struct folio *src, + enum migrate_reason reason) +{ + /* + * Compaction can migrate also non-LRU pages which are + * not accounted to NR_ISOLATED_*. They can be recognized + * as __PageMovable + */ + if (likely(!__folio_test_movable(src))) + mod_node_page_state(folio_pgdat(src), NR_ISOLATED_ANON + + folio_is_file_lru(src), -folio_nr_pages(src)); + + if (reason != MR_MEMORY_FAILURE) + /* We release the page in page_handle_poison. */ + folio_put(src); +} + +/* Obtain the lock on page, remove all ptes. */ +static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page, + unsigned long private, struct folio *src, + struct folio **dstp, int force, + enum migrate_mode mode, enum migrate_reason reason, + struct list_head *ret) { struct folio *dst; - int rc = MIGRATEPAGE_SUCCESS; + int rc = MIGRATEPAGE_UNMAP; struct page *newpage = NULL; if (!thp_migration_supported() && folio_test_transhuge(src)) @@ -1182,20 +1239,50 @@ static int unmap_and_move(new_page_t get_new_page, folio_clear_active(src); folio_clear_unevictable(src); /* free_pages_prepare() will clear PG_isolated. */ - goto out; + list_del(&src->lru); + migrate_folio_done(src, reason); + return MIGRATEPAGE_SUCCESS; } newpage = get_new_page(&src->page, private); if (!newpage) return -ENOMEM; dst = page_folio(newpage); + *dstp = dst; dst->private = NULL; - rc = __unmap_and_move(src, dst, force, mode); + rc = __migrate_folio_unmap(src, dst, force, mode); + if (rc == MIGRATEPAGE_UNMAP) + return rc; + + /* + * A page that has not been migrated will have kept its + * references and be restored. + */ + /* restore the folio to right list. */ + if (rc != -EAGAIN) + list_move_tail(&src->lru, ret); + + if (put_new_page) + put_new_page(&dst->page, private); + else + folio_put(dst); + + return rc; +} + +/* Migrate the folio to the newly allocated folio in dst. */ +static int migrate_folio_move(free_page_t put_new_page, unsigned long private, + struct folio *src, struct folio *dst, + enum migrate_mode mode, enum migrate_reason reason, + struct list_head *ret) +{ + int rc; + + rc = __migrate_folio_move(src, dst, mode); if (rc == MIGRATEPAGE_SUCCESS) set_page_owner_migrate_reason(&dst->page, reason); -out: if (rc != -EAGAIN) { /* * A folio that has been migrated has all references @@ -1211,20 +1298,7 @@ static int unmap_and_move(new_page_t get_new_page, * we want to retry. */ if (rc == MIGRATEPAGE_SUCCESS) { - /* - * Compaction can migrate also non-LRU folios which are - * not accounted to NR_ISOLATED_*. They can be recognized - * as __folio_test_movable - */ - if (likely(!__folio_test_movable(src))) - mod_node_page_state(folio_pgdat(src), NR_ISOLATED_ANON + - folio_is_file_lru(src), -folio_nr_pages(src)); - - if (reason != MR_MEMORY_FAILURE) - /* - * We release the folio in page_handle_poison. - */ - folio_put(src); + migrate_folio_done(src, reason); } else { if (rc != -EAGAIN) list_add_tail(&src->lru, ret); @@ -1499,7 +1573,7 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, int pass = 0; bool is_large = false; bool is_thp = false; - struct folio *folio, *folio2; + struct folio *folio, *folio2, *dst = NULL; int rc, nr_pages; LIST_HEAD(split_folios); bool nosplit = (reason == MR_NUMA_MISPLACED); @@ -1524,9 +1598,13 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, cond_resched(); - rc = unmap_and_move(get_new_page, put_new_page, - private, folio, pass > 2, mode, - reason, ret_folios); + rc = migrate_folio_unmap(get_new_page, put_new_page, private, + folio, &dst, pass > 2, mode, + reason, ret_folios); + if (rc == MIGRATEPAGE_UNMAP) + rc = migrate_folio_move(put_new_page, private, + folio, dst, mode, + reason, ret_folios); /* * The rules are: * Success: folio will be freed
This is a preparation patch to batch the folio unmapping and moving. In this patch, unmap_and_move() is split to migrate_folio_unmap() and migrate_folio_move(). So, we can batch _unmap() and _move() in different loops later. To pass some information between unmap and move, the original unused dst->mapping and dst->private are used. Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Matthew Wilcox <willy@infradead.org> Cc: Bharata B Rao <bharata@amd.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: haoxin <xhao@linux.alibaba.com> --- include/linux/migrate.h | 1 + mm/migrate.c | 162 +++++++++++++++++++++++++++++----------- 2 files changed, 121 insertions(+), 42 deletions(-)