From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4CE99C74A5B for ; Thu, 23 Mar 2023 21:15:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229690AbjCWVPZ (ORCPT ); Thu, 23 Mar 2023 17:15:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46050 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229642AbjCWVPY (ORCPT ); Thu, 23 Mar 2023 17:15:24 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3114C24495 for ; Thu, 23 Mar 2023 14:15:23 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id D74F6B82251 for ; Thu, 23 Mar 2023 21:15:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 983BDC433D2; Thu, 23 Mar 2023 21:15:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1679606120; bh=39wAqWI8t1rKU54Lt4qNvuJTCDyGGcsF7aULoT0U2Vg=; h=Date:To:From:Subject:From; b=lEXw3BHVCkJDHRM2rBmfeMRkZsjDo5nZ9pPzhvFAZYrgNY4sCPd1quZoSPgbT1mDX PvErjxn5Q4LgYt05abSSPDinYIwKu1OA2ghMGbJJEZzcnKYgSBruBZt0BDnOpZ5tI+ zDKMI7KOkF7y5VCnhBJzRfyFZ/f/YNGF4DIfu4aM= Date: Thu, 23 Mar 2023 14:15:20 -0700 To: mm-commits@vger.kernel.org, willy@infradead.org, shy828301@gmail.com, peterx@redhat.com, kirill@shutemov.name, jiaqiyan@google.com, hughd@google.com, david@redhat.com, stevensd@chromium.org, akpm@linux-foundation.org From: Andrew Morton Subject: [to-be-updated] mm-khugepaged-refactor-collapse_file-control-flow.patch removed from -mm tree Message-Id: <20230323211520.983BDC433D2@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The quilt patch titled Subject: mm/khugepaged: refactor collapse_file control flow has been removed from the -mm tree. Its filename was mm-khugepaged-refactor-collapse_file-control-flow.patch This patch was dropped because an updated version will be merged ------------------------------------------------------ From: David Stevens Subject: mm/khugepaged: refactor collapse_file control flow Date: Tue, 7 Mar 2023 14:20:34 +0900 Patch series "mm/khugepaged: fix khugepaged+shmem races", v5. Fix two races in khugepaged+shmem that cause issues with userfaultfd and lseek, respectively. This patch (of 3): Add a rollback label to deal with failure, instead of continuously checking for RESULT_SUCCESS, to make it easier to add more failure cases. The refactoring also allows the collapse_file tracepoint to include hpage on success (instead of NULL). Link: https://lkml.kernel.org/r/20230307052036.1520708-1-stevensd@google.com Link: https://lkml.kernel.org/r/20230307052036.1520708-2-stevensd@google.com Signed-off-by: David Stevens Acked-by: Peter Xu Reviewed-by: Yang Shi Cc: David Hildenbrand Cc: Hugh Dickins Cc: Jiaqi Yan Cc: "Kirill A . Shutemov" Cc: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton --- --- a/mm/khugepaged.c~mm-khugepaged-refactor-collapse_file-control-flow +++ a/mm/khugepaged.c @@ -1907,6 +1907,12 @@ static int collapse_file(struct mm_struc if (result != SCAN_SUCCEED) goto out; + __SetPageLocked(hpage); + if (is_shmem) + __SetPageSwapBacked(hpage); + hpage->index = start; + hpage->mapping = mapping; + /* * Ensure we have slots for all the pages in the range. This is * almost certainly a no-op because most of the pages must be present @@ -1919,16 +1925,10 @@ static int collapse_file(struct mm_struc xas_unlock_irq(&xas); if (!xas_nomem(&xas, GFP_KERNEL)) { result = SCAN_FAIL; - goto out; + goto rollback; } } while (1); - __SetPageLocked(hpage); - if (is_shmem) - __SetPageSwapBacked(hpage); - hpage->index = start; - hpage->mapping = mapping; - /* * At this point the hpage is locked and not up-to-date. * It's safe to insert it into the page cache, because nobody would @@ -2145,129 +2145,126 @@ xa_unlocked: */ try_to_unmap_flush(); - if (result == SCAN_SUCCEED) { - /* - * Replacing old pages with new one has succeeded, now we - * attempt to copy the contents. - */ - index = start; - list_for_each_entry(page, &pagelist, lru) { - while (index < page->index) { - clear_highpage(hpage + (index % HPAGE_PMD_NR)); - index++; - } - if (copy_mc_highpage(hpage + (page->index % HPAGE_PMD_NR), - page) > 0) { - result = SCAN_COPY_MC; - break; - } - index++; - } - while (result == SCAN_SUCCEED && index < end) { + if (result != SCAN_SUCCEED) + goto rollback; + + /* + * Replacing old pages with new one has succeeded, now we + * attempt to copy the contents. + */ + index = start; + list_for_each_entry(page, &pagelist, lru) { + while (index < page->index) { clear_highpage(hpage + (index % HPAGE_PMD_NR)); index++; } - } - - if (result == SCAN_SUCCEED) { - /* - * Copying old pages to huge one has succeeded, now we - * need to free the old pages. - */ - list_for_each_entry_safe(page, tmp, &pagelist, lru) { - list_del(&page->lru); - page->mapping = NULL; - page_ref_unfreeze(page, 1); - ClearPageActive(page); - ClearPageUnevictable(page); - unlock_page(page); - put_page(page); + if (copy_mc_highpage(hpage + (page->index % HPAGE_PMD_NR), page) > 0) { + result = SCAN_COPY_MC; + goto rollback; } + index++; + } + while (index < end) { + clear_highpage(hpage + (index % HPAGE_PMD_NR)); + index++; + } - xas_lock_irq(&xas); - if (is_shmem) - __mod_lruvec_page_state(hpage, NR_SHMEM_THPS, nr); - else - __mod_lruvec_page_state(hpage, NR_FILE_THPS, nr); - - if (nr_none) { - __mod_lruvec_page_state(hpage, NR_FILE_PAGES, nr_none); - /* nr_none is always 0 for non-shmem. */ - __mod_lruvec_page_state(hpage, NR_SHMEM, nr_none); - } - /* Join all the small entries into a single multi-index entry. */ - xas_set_order(&xas, start, HPAGE_PMD_ORDER); - xas_store(&xas, hpage); - xas_unlock_irq(&xas); + /* + * Copying old pages to huge one has succeeded, now we + * need to free the old pages. + */ + list_for_each_entry_safe(page, tmp, &pagelist, lru) { + list_del(&page->lru); + page->mapping = NULL; + page_ref_unfreeze(page, 1); + ClearPageActive(page); + ClearPageUnevictable(page); + unlock_page(page); + put_page(page); + } - folio = page_folio(hpage); - folio_mark_uptodate(folio); - folio_ref_add(folio, HPAGE_PMD_NR - 1); - - if (is_shmem) - folio_mark_dirty(folio); - folio_add_lru(folio); + xas_lock_irq(&xas); + if (is_shmem) + __mod_lruvec_page_state(hpage, NR_SHMEM_THPS, nr); + else + __mod_lruvec_page_state(hpage, NR_FILE_THPS, nr); + + if (nr_none) { + __mod_lruvec_page_state(hpage, NR_FILE_PAGES, nr_none); + /* nr_none is always 0 for non-shmem. */ + __mod_lruvec_page_state(hpage, NR_SHMEM, nr_none); + } + /* Join all the small entries into a single multi-index entry. */ + xas_set_order(&xas, start, HPAGE_PMD_ORDER); + xas_store(&xas, hpage); + xas_unlock_irq(&xas); - /* - * Remove pte page tables, so we can re-fault the page as huge. - */ - result = retract_page_tables(mapping, start, mm, addr, hpage, - cc); - unlock_page(hpage); - hpage = NULL; - } else { - /* Something went wrong: roll back page cache changes */ - xas_lock_irq(&xas); - if (nr_none) { - mapping->nrpages -= nr_none; - shmem_uncharge(mapping->host, nr_none); - } + folio = page_folio(hpage); + folio_mark_uptodate(folio); + folio_ref_add(folio, HPAGE_PMD_NR - 1); - xas_set(&xas, start); - xas_for_each(&xas, page, end - 1) { - page = list_first_entry_or_null(&pagelist, - struct page, lru); - if (!page || xas.xa_index < page->index) { - if (!nr_none) - break; - nr_none--; - /* Put holes back where they were */ - xas_store(&xas, NULL); - continue; - } + if (is_shmem) + folio_mark_dirty(folio); + folio_add_lru(folio); - VM_BUG_ON_PAGE(page->index != xas.xa_index, page); + /* + * Remove pte page tables, so we can re-fault the page as huge. + */ + result = retract_page_tables(mapping, start, mm, addr, hpage, + cc); + unlock_page(hpage); + goto out; + +rollback: + /* Something went wrong: roll back page cache changes */ + xas_lock_irq(&xas); + if (nr_none) { + mapping->nrpages -= nr_none; + shmem_uncharge(mapping->host, nr_none); + } - /* Unfreeze the page. */ - list_del(&page->lru); - page_ref_unfreeze(page, 2); - xas_store(&xas, page); - xas_pause(&xas); - xas_unlock_irq(&xas); - unlock_page(page); - putback_lru_page(page); - xas_lock_irq(&xas); + xas_set(&xas, start); + xas_for_each(&xas, page, end - 1) { + page = list_first_entry_or_null(&pagelist, + struct page, lru); + if (!page || xas.xa_index < page->index) { + if (!nr_none) + break; + nr_none--; + /* Put holes back where they were */ + xas_store(&xas, NULL); + continue; } - VM_BUG_ON(nr_none); - /* - * Undo the updates of filemap_nr_thps_inc for non-SHMEM file only. - * This undo is not needed unless failure is due to SCAN_COPY_MC. - */ - if (!is_shmem && result == SCAN_COPY_MC) - filemap_nr_thps_dec(mapping); + VM_BUG_ON_PAGE(page->index != xas.xa_index, page); + + /* Unfreeze the page. */ + list_del(&page->lru); + page_ref_unfreeze(page, 2); + xas_store(&xas, page); + xas_pause(&xas); xas_unlock_irq(&xas); - - hpage->mapping = NULL; + unlock_page(page); + putback_lru_page(page); + xas_lock_irq(&xas); } + VM_BUG_ON(nr_none); + /* + * Undo the updates of filemap_nr_thps_inc for non-SHMEM file only. + * This undo is not needed unless failure is due to SCAN_COPY_MC. + */ + if (!is_shmem && result == SCAN_COPY_MC) + filemap_nr_thps_dec(mapping); + + xas_unlock_irq(&xas); + + hpage->mapping = NULL; + + unlock_page(hpage); + put_page(hpage); - if (hpage) - unlock_page(hpage); out: VM_BUG_ON(!list_empty(&pagelist)); - if (hpage) - put_page(hpage); - trace_mm_khugepaged_collapse_file(mm, hpage, index, is_shmem, addr, file, nr, result); return result; } _ Patches currently in -mm which might be from stevensd@chromium.org are mm-khugepaged-skip-shmem-with-userfaultfd.patch mm-khugepaged-maintain-page-cache-uptodate-flag.patch