From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f71.google.com (mail-wm0-f71.google.com [74.125.82.71]) by kanga.kvack.org (Postfix) with ESMTP id 1F0186B0253 for ; Sat, 11 Jun 2016 15:16:17 -0400 (EDT) Received: by mail-wm0-f71.google.com with SMTP id 4so11139131wmz.1 for ; Sat, 11 Jun 2016 12:16:17 -0700 (PDT) Received: from mail-wm0-x241.google.com (mail-wm0-x241.google.com. [2a00:1450:400c:c09::241]) by mx.google.com with ESMTPS id f5si20895790wje.247.2016.06.11.12.16.15 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 11 Jun 2016 12:16:15 -0700 (PDT) Received: by mail-wm0-x241.google.com with SMTP id n184so5831330wmn.1 for ; Sat, 11 Jun 2016 12:16:15 -0700 (PDT) From: Ebru Akagunduz Subject: [RFC PATCH 1/3] mm, thp: revert allocstall comparing Date: Sat, 11 Jun 2016 22:15:59 +0300 Message-Id: <1465672561-29608-2-git-send-email-ebru.akagunduz@gmail.com> In-Reply-To: <1465672561-29608-1-git-send-email-ebru.akagunduz@gmail.com> References: <1465672561-29608-1-git-send-email-ebru.akagunduz@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Cc: hughd@google.com, riel@redhat.com, akpm@linux-foundation.org, kirill.shutemov@linux.intel.com, n-horiguchi@ah.jp.nec.com, aarcange@redhat.com, iamjoonsoo.kim@lge.com, gorcunov@openvz.org, linux-kernel@vger.kernel.org, mgorman@suse.de, rientjes@google.com, vbabka@suse.cz, aneesh.kumar@linux.vnet.ibm.com, hannes@cmpxchg.org, mhocko@suse.cz, boaz@plexistor.com, Ebru Akagunduz This patch takes back allocstall comparing when deciding whether swapin worthwhile because it does not work, if vmevent disabled. Related commit: http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=2548306628308aa6a326640d345a737bc898941d Signed-off-by: Ebru Akagunduz --- mm/khugepaged.c | 31 ++++++++----------------------- 1 file changed, 8 insertions(+), 23 deletions(-) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 0ac63f7..e3d8da7 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -68,7 +68,6 @@ static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait); */ static unsigned int khugepaged_max_ptes_none __read_mostly; static unsigned int khugepaged_max_ptes_swap __read_mostly; -static unsigned long allocstall; static int khugepaged(void *none); @@ -926,7 +925,6 @@ static void collapse_huge_page(struct mm_struct *mm, struct page *new_page; spinlock_t *pmd_ptl, *pte_ptl; int isolated = 0, result = 0; - unsigned long swap, curr_allocstall; struct mem_cgroup *memcg; unsigned long mmun_start; /* For mmu_notifiers */ unsigned long mmun_end; /* For mmu_notifiers */ @@ -955,8 +953,6 @@ static void collapse_huge_page(struct mm_struct *mm, goto out_nolock; } - swap = get_mm_counter(mm, MM_SWAPENTS); - curr_allocstall = sum_vm_event(ALLOCSTALL); down_read(&mm->mmap_sem); result = hugepage_vma_revalidate(mm, address); if (result) { @@ -972,22 +968,15 @@ static void collapse_huge_page(struct mm_struct *mm, up_read(&mm->mmap_sem); goto out_nolock; } - /* - * Don't perform swapin readahead when the system is under pressure, - * to avoid unnecessary resource consumption. + * __collapse_huge_page_swapin always returns with mmap_sem + * locked. If it fails, release mmap_sem and jump directly + * out. Continuing to collapse causes inconsistency. */ - if (allocstall == curr_allocstall && swap != 0) { - /* - * __collapse_huge_page_swapin always returns with mmap_sem - * locked. If it fails, release mmap_sem and jump directly - * out. Continuing to collapse causes inconsistency. - */ - if (!__collapse_huge_page_swapin(mm, vma, address, pmd)) { - mem_cgroup_cancel_charge(new_page, memcg, true); - up_read(&mm->mmap_sem); - goto out_nolock; - } + if (!__collapse_huge_page_swapin(mm, vma, address, pmd)) { + mem_cgroup_cancel_charge(new_page, memcg, true); + up_read(&mm->mmap_sem); + goto out_nolock; } up_read(&mm->mmap_sem); @@ -1822,7 +1811,6 @@ static void khugepaged_wait_work(void) if (!scan_sleep_jiffies) return; - allocstall = sum_vm_event(ALLOCSTALL); khugepaged_sleep_expire = jiffies + scan_sleep_jiffies; wait_event_freezable_timeout(khugepaged_wait, khugepaged_should_wakeup(), @@ -1830,10 +1818,8 @@ static void khugepaged_wait_work(void) return; } - if (khugepaged_enabled()) { - allocstall = sum_vm_event(ALLOCSTALL); + if (khugepaged_enabled()) wait_event_freezable(khugepaged_wait, khugepaged_wait_event()); - } } static int khugepaged(void *none) @@ -1842,7 +1828,6 @@ static int khugepaged(void *none) set_freezable(); set_user_nice(current, MAX_NICE); - allocstall = sum_vm_event(ALLOCSTALL); while (!kthread_should_stop()) { khugepaged_do_scan(); -- 1.9.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org