From: Jérôme Glisse <jglisse@xxxxxxxxxx> Subject: mm/memcontrol: support MEMORY_DEVICE_PRIVATE HMM pages (private or public device pages) are ZONE_DEVICE page and thus need special handling when it comes to lru or refcount. This patch make sure that memcontrol properly handle those when it face them. Those pages are use like regular pages in a process address space either as anonymous page or as file back page. So from memcg point of view we want to handle them like regular page for now at least. Link: http://lkml.kernel.org/r/20170817000548.32038-11-jglisse@xxxxxxxxxx Signed-off-by: Jérôme Glisse <jglisse@xxxxxxxxxx> Acked-by: Balbir Singh <bsingharora@xxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx> Cc: Aneesh Kumar <aneesh.kumar@xxxxxxxxxxxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: David Nellans <dnellans@xxxxxxxxxx> Cc: Evgeny Baskakov <ebaskakov@xxxxxxxxxx> Cc: John Hubbard <jhubbard@xxxxxxxxxx> Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Mark Hairgrove <mhairgrove@xxxxxxxxxx> Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx> Cc: Sherry Cheung <SCheung@xxxxxxxxxx> Cc: Subhash Gutti <sgutti@xxxxxxxxxx> Cc: Bob Liu <liubo95@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/memremap.c | 1 mm/memcontrol.c | 52 ++++++++++++++++++++++++++++++++++++++++---- 2 files changed, 49 insertions(+), 4 deletions(-) diff -puN kernel/memremap.c~mm-memcontrol-support-memory_device_private-v4 kernel/memremap.c --- a/kernel/memremap.c~mm-memcontrol-support-memory_device_private-v4 +++ a/kernel/memremap.c @@ -516,6 +516,7 @@ void put_zone_device_private_page(struct __ClearPageWaiters(page); page->mapping = NULL; + mem_cgroup_uncharge(page); page->pgmap->page_free(page, page->pgmap->data); } else if (!count) diff -puN mm/memcontrol.c~mm-memcontrol-support-memory_device_private-v4 mm/memcontrol.c --- a/mm/memcontrol.c~mm-memcontrol-support-memory_device_private-v4 +++ a/mm/memcontrol.c @@ -4414,12 +4414,13 @@ enum mc_target_type { MC_TARGET_NONE = 0, MC_TARGET_PAGE, MC_TARGET_SWAP, + MC_TARGET_DEVICE, }; static struct page *mc_handle_present_pte(struct vm_area_struct *vma, unsigned long addr, pte_t ptent) { - struct page *page = vm_normal_page(vma, addr, ptent); + struct page *page = _vm_normal_page(vma, addr, ptent, true); if (!page || !page_mapped(page)) return NULL; @@ -4436,7 +4437,7 @@ static struct page *mc_handle_present_pt return page; } -#ifdef CONFIG_SWAP +#if defined(CONFIG_SWAP) || defined(CONFIG_DEVICE_PRIVATE) static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, pte_t ptent, swp_entry_t *entry) { @@ -4445,6 +4446,23 @@ static struct page *mc_handle_swap_pte(s if (!(mc.flags & MOVE_ANON) || non_swap_entry(ent)) return NULL; + + /* + * Handle MEMORY_DEVICE_PRIVATE which are ZONE_DEVICE page belonging to + * a device and because they are not accessible by CPU they are store + * as special swap entry in the CPU page table. + */ + if (is_device_private_entry(ent)) { + page = device_private_entry_to_page(ent); + /* + * MEMORY_DEVICE_PRIVATE means ZONE_DEVICE page and which have + * a refcount of 1 when free (unlike normal page) + */ + if (!page_ref_add_unless(page, 1, 1)) + return NULL; + return page; + } + /* * Because lookup_swap_cache() updates some statistics counter, * we call find_get_page() with swapper_space directly. @@ -4605,6 +4623,12 @@ out: * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a * target for charge migration. if @target is not NULL, the entry is stored * in target->ent. + * 3(MC_TARGET_DEVICE): like MC_TARGET_PAGE but page is MEMORY_DEVICE_PRIVATE + * (so ZONE_DEVICE page and thus not on the lru). For now we such page is + * charge like a regular page would be as for all intent and purposes it is + * just special memory taking the place of a regular page. + * + * See Documentations/vm/hmm.txt and include/linux/hmm.h * * Called with pte lock held. */ @@ -4633,6 +4657,8 @@ static enum mc_target_type get_mctgt_typ */ if (page->mem_cgroup == mc.from) { ret = MC_TARGET_PAGE; + if (is_device_private_page(page)) + ret = MC_TARGET_DEVICE; if (target) target->page = page; } @@ -4700,6 +4726,11 @@ static int mem_cgroup_count_precharge_pt ptl = pmd_trans_huge_lock(pmd, vma); if (ptl) { + /* + * Note their can not be MC_TARGET_DEVICE for now as we do not + * support transparent huge page with MEMORY_DEVICE_PUBLIC or + * MEMORY_DEVICE_PRIVATE but this might change. + */ if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE) mc.precharge += HPAGE_PMD_NR; spin_unlock(ptl); @@ -4915,6 +4946,14 @@ static int mem_cgroup_move_charge_pte_ra putback_lru_page(page); } put_page(page); + } else if (target_type == MC_TARGET_DEVICE) { + page = target.page; + if (!mem_cgroup_move_account(page, true, + mc.from, mc.to)) { + mc.precharge -= HPAGE_PMD_NR; + mc.moved_charge += HPAGE_PMD_NR; + } + put_page(page); } spin_unlock(ptl); return 0; @@ -4926,12 +4965,16 @@ retry: pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); for (; addr != end; addr += PAGE_SIZE) { pte_t ptent = *(pte++); + bool device = false; swp_entry_t ent; if (!mc.precharge) break; switch (get_mctgt_type(vma, addr, ptent, &target)) { + case MC_TARGET_DEVICE: + device = true; + /* fall through */ case MC_TARGET_PAGE: page = target.page; /* @@ -4942,7 +4985,7 @@ retry: */ if (PageTransCompound(page)) goto put; - if (isolate_lru_page(page)) + if (!device && isolate_lru_page(page)) goto put; if (!mem_cgroup_move_account(page, false, mc.from, mc.to)) { @@ -4950,7 +4993,8 @@ retry: /* we uncharge from mc.from later. */ mc.moved_charge++; } - putback_lru_page(page); + if (!device) + putback_lru_page(page); put: /* get_mctgt_type() gets the page */ put_page(page); break; _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
