On Tue 04-09-18 11:33:45, Alexander Duyck wrote: > From: Alexander Duyck <alexander.h.duyck@xxxxxxxxx> > > It doesn't make much sense to use the atomic SetPageReserved at init time > when we are using memset to clear the memory and manipulating the page > flags via simple "&=" and "|=" operations in __init_single_page. > > This patch adds a non-atomic version __SetPageReserved that can be used > during page init and shows about a 10% improvement in initialization times > on the systems I have available for testing. I agree with Dave about a comment is due. I am also quite surprised that this leads to such a large improvement. Could you be more specific about your test and machines you were testing on? Other than that the patch makes sense to me. > Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxx> With the above addressed, feel free to add Acked-by: Michal Hocko <mhocko@xxxxxxxx> Thanks! > --- > include/linux/page-flags.h | 1 + > mm/page_alloc.c | 4 ++-- > 2 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h > index 74bee8cecf4c..57ec3fef7e9f 100644 > --- a/include/linux/page-flags.h > +++ b/include/linux/page-flags.h > @@ -292,6 +292,7 @@ static inline int PagePoisoned(const struct page *page) > > PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) > __CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) > + __SETPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) > PAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) > __CLEARPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) > __SETPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 05e983f42316..9c7d6e971630 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -1231,7 +1231,7 @@ void __meminit reserve_bootmem_region(phys_addr_t start, phys_addr_t end) > /* Avoid false-positive PageTail() */ > INIT_LIST_HEAD(&page->lru); > > - SetPageReserved(page); > + __SetPageReserved(page); > } > } > } > @@ -5518,7 +5518,7 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone, > page = pfn_to_page(pfn); > __init_single_page(page, pfn, zone, nid); > if (context == MEMMAP_HOTPLUG) > - SetPageReserved(page); > + __SetPageReserved(page); > > /* > * Mark the block movable so that blocks are reserved for > -- Michal Hocko SUSE Labs
