On 7/9/20 9:34 AM, Zi Yan wrote: > On 9 Jul 2020, at 11:34, Randy Dunlap wrote: > >> Hi, >> >> I have a few comments on this. >> >> a. I reported it very early and should have been Cc-ed. >> >> b. A patch that applies to mmotm or linux-next would have been better >> than a full replacement patch. >> >> c. I tried replacing what I believe is the correct/same patch file in mmotm >> and still have build errors. >> >> (more below) >> >> On 7/9/20 2:39 AM, Anshuman Khandual wrote: >> >>> --- >>> Applies on 5.8-rc4. >>> >>> Changes in V4: >>> >>> - Changed THP_MIGRATION_FAILURE as THP_MIGRATION_FAIL per John >>> - Dropped all conditional 'if' blocks in migrate_pages() per Andrew and John >>> - Updated migration events documentation per John >>> - Updated thp_nr_pages variable as nr_subpages for an expected merge conflict >>> - Moved all new THP vmstat events into CONFIG_MIGRATION >>> - Updated Cc list with Documentation/ and tracing related addresses >>> >>> Changes in V3: (https://patchwork.kernel.org/patch/11647237/) >>> >>> - Formatted new events documentation with 'fmt' tool per Matthew >>> - Made events universally available i.e dropped ARCH_ENABLE_THP_MIGRATION >>> - Added THP_MIGRATION_SPLIT >>> - Updated trace_mm_migrate_pages() with THP events >>> - Made THP events update normal page migration events as well >>> >>> Changes in V2: (https://patchwork.kernel.org/patch/11586893/) >>> >>> - Dropped PMD reference both from code and commit message per Matthew >>> - Added documentation and updated the commit message per Daniel >>> >>> Changes in V1: (https://patchwork.kernel.org/patch/11564497/) >>> >>> - Changed function name as thp_pmd_migration_success() per John >>> - Folded in a fix (https://patchwork.kernel.org/patch/11563009/) from Hugh >>> >>> Changes in RFC V2: (https://patchwork.kernel.org/patch/11554861/) >>> >>> - Decopupled and renamed VM events from their implementation per Zi and John >>> - Added THP_PMD_MIGRATION_FAILURE VM event upon allocation failure and split >>> >>> Changes in RFC V1: (https://patchwork.kernel.org/patch/11542055/) >>> >>> Documentation/vm/page_migration.rst | 27 +++++++++++++++ >>> include/linux/vm_event_item.h | 3 ++ >>> include/trace/events/migrate.h | 17 ++++++++-- >>> mm/migrate.c | 52 ++++++++++++++++++++++++----- >>> mm/vmstat.c | 3 ++ >>> 5 files changed, 91 insertions(+), 11 deletions(-) >>> >> >>> diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h >>> index 24fc7c3ae7d6..2e6ca53b9bbd 100644 >>> --- a/include/linux/vm_event_item.h >>> +++ b/include/linux/vm_event_item.h >>> @@ -56,6 +56,9 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, >>> #endif >>> #ifdef CONFIG_MIGRATION >>> PGMIGRATE_SUCCESS, PGMIGRATE_FAIL, >>> + THP_MIGRATION_SUCCESS, >>> + THP_MIGRATION_FAIL, >>> + THP_MIGRATION_SPLIT, >> >> These 3 new symbols are still only present if CONFIG_MIGRATION=y, but the build errors >> are using these symbols even when CONFIG_MIGRATION is not set. >> >>> #endif >>> #ifdef CONFIG_COMPACTION >>> COMPACTMIGRATE_SCANNED, COMPACTFREE_SCANNED, >> >>> diff --git a/mm/migrate.c b/mm/migrate.c >>> index f37729673558..c706e3576cfc 100644 >>> --- a/mm/migrate.c >>> +++ b/mm/migrate.c >>> @@ -1429,22 +1429,35 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, >>> enum migrate_mode mode, int reason) >>> { >>> int retry = 1; >>> + int thp_retry = 1; >>> int nr_failed = 0; >>> int nr_succeeded = 0; >>> + int nr_thp_succeeded = 0; >>> + int nr_thp_failed = 0; >>> + int nr_thp_split = 0; >>> int pass = 0; >>> + bool is_thp = false; >>> struct page *page; >>> struct page *page2; >>> int swapwrite = current->flags & PF_SWAPWRITE; >>> - int rc; >>> + int rc, nr_subpages; >>> >>> if (!swapwrite) >>> current->flags |= PF_SWAPWRITE; >>> >>> - for(pass = 0; pass < 10 && retry; pass++) { >>> + for (pass = 0; pass < 10 && (retry || thp_retry); pass++) { >>> retry = 0; >>> + thp_retry = 0; >>> >>> list_for_each_entry_safe(page, page2, from, lru) { >>> retry: >>> + /* >>> + * THP statistics is based on the source huge page. >>> + * Capture required information that might get lost >>> + * during migration. >>> + */ >>> + is_thp = PageTransHuge(page); >>> + nr_subpages = hpage_nr_pages(page); >>> cond_resched(); >>> >>> if (PageHuge(page)) >>> @@ -1475,15 +1488,30 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, >>> unlock_page(page); >>> if (!rc) { >>> list_safe_reset_next(page, page2, lru); >>> + nr_thp_split++; >>> goto retry; >>> } >>> } >>> + if (is_thp) { >>> + nr_thp_failed++; >>> + nr_failed += nr_subpages; >>> + goto out; >>> + } >>> nr_failed++; >>> goto out; >>> case -EAGAIN: >>> + if (is_thp) { >>> + thp_retry++; >>> + break; >>> + } >>> retry++; >>> break; >>> case MIGRATEPAGE_SUCCESS: >>> + if (is_thp) { >>> + nr_thp_succeeded++; >>> + nr_succeeded += nr_subpages; >>> + break; >>> + } >>> nr_succeeded++; >>> break; >>> default: >>> @@ -1493,19 +1521,27 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, >>> * removed from migration page list and not >>> * retried in the next outer loop. >>> */ >>> + if (is_thp) { >>> + nr_thp_failed++; >>> + nr_failed += nr_subpages; >>> + break; >>> + } >>> nr_failed++; >>> break; >>> } >>> } >>> } >>> - nr_failed += retry; >>> + nr_failed += retry + thp_retry; >>> + nr_thp_failed += thp_retry; >>> rc = nr_failed; >>> out: >>> - if (nr_succeeded) >>> - count_vm_events(PGMIGRATE_SUCCESS, nr_succeeded); >>> - if (nr_failed) >>> - count_vm_events(PGMIGRATE_FAIL, nr_failed); >>> - trace_mm_migrate_pages(nr_succeeded, nr_failed, mode, reason); >>> + count_vm_events(PGMIGRATE_SUCCESS, nr_succeeded); >>> + count_vm_events(PGMIGRATE_FAIL, nr_failed); >>> + count_vm_events(THP_MIGRATION_SUCCESS, nr_thp_succeeded); >>> + count_vm_events(THP_MIGRATION_FAIL, nr_thp_failed); >>> + count_vm_events(THP_MIGRATION_SPLIT, nr_thp_split); >> >> These references still cause build errors. >> >>> + trace_mm_migrate_pages(nr_succeeded, nr_failed, nr_thp_succeeded, >>> + nr_thp_failed, nr_thp_split, mode, reason); >>> >>> if (!swapwrite) >>> current->flags &= ~PF_SWAPWRITE; >>> diff --git a/mm/vmstat.c b/mm/vmstat.c >>> index 3fb23a21f6dd..09914a4bfee4 100644 >>> --- a/mm/vmstat.c >>> +++ b/mm/vmstat.c >>> @@ -1234,6 +1234,9 @@ const char * const vmstat_text[] = { >>> #ifdef CONFIG_MIGRATION >>> "pgmigrate_success", >>> "pgmigrate_fail", >>> + "thp_migration_success", >>> + "thp_migration_fail", >>> + "thp_migration_split", >>> #endif >>> #ifdef CONFIG_COMPACTION >>> "compact_migrate_scanned", >>> >> > > Which arch are you building? I did not see any error > after applying this patch on mmotm (reverting the existing ones) > and compiling them on x86_64. I used make x86_64_defconfig and > unselected COMPACTION and MIGRATION. Hi, I am trying to build x86_64. Maybe I am just having trouble replacing the patch file. Like I tried to say, I would prefer to see an incremental patch to fix mmotm or linux-next. > mm/migrate.c and added vm events will not be used > if CONFIG_MIGRATION is unchecked. Why would they cause compilation errors? AFAICT, the patch adds these calls: + count_vm_events(PGMIGRATE_SUCCESS, nr_succeeded); + count_vm_events(PGMIGRATE_FAIL, nr_failed); + count_vm_events(THP_MIGRATION_SUCCESS, nr_thp_succeeded); + count_vm_events(THP_MIGRATION_FAIL, nr_thp_failed); + count_vm_events(THP_MIGRATION_SPLIT, nr_thp_split); + trace_mm_migrate_pages(nr_succeeded, nr_failed, nr_thp_succeeded, + nr_thp_failed, nr_thp_split, mode, reason); even when CONFIG_MIGRATION is not set, but then the THP_MIGRATIION_SUCCESS/FAIL/SPLIT symbols are not defined. -- ~Randy
