Trying to set or clear PG_lru on tail pages has been considered buggy. Enforce this rule by changing the policy for PG_lru from PF_HEAD to PF_NO_TAIL. This means setting or clearing PG_lru on tail pages won't be "corrected" by compound_page(). Such "correction" isn't helpful -- even if a piece of buggy code has gotten away with compound_page(tail)->flags, it will run into trouble with lru list addition and deletion because they use tail->lru rather than compound_page(tail)->lru. bloat-o-meter result: add/remove: 0/0 grow/shrink: 0/11 up/down: 0/-535 (-535) Signed-off-by: Yu Zhao <yuzhao@xxxxxxxxxx> --- include/linux/page-flags.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 1995208a3763..c9626e54df8d 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -333,8 +333,8 @@ PAGEFLAG(Referenced, referenced, PF_HEAD) __SETPAGEFLAG(Referenced, referenced, PF_HEAD) PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD) __CLEARPAGEFLAG(Dirty, dirty, PF_HEAD) -PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD) - TESTCLEARFLAG(LRU, lru, PF_HEAD) +PAGEFLAG(LRU, lru, PF_NO_TAIL) __CLEARPAGEFLAG(LRU, lru, PF_NO_TAIL) + TESTCLEARFLAG(LRU, lru, PF_NO_TAIL) PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD) TESTCLEARFLAG(Active, active, PF_HEAD) PAGEFLAG(Workingset, workingset, PF_HEAD) -- 2.30.1.766.gb4fecdf3b7-goog
