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. mm/migrate.c and added vm events will not be used if CONFIG_MIGRATION is unchecked. Why would they cause compilation errors? — Best Regards, Yan Zi
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