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 DDB98C4167B for ; Thu, 7 Dec 2023 00:13:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1442149AbjLGANq (ORCPT ); Wed, 6 Dec 2023 19:13:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45814 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1442095AbjLGANd (ORCPT ); Wed, 6 Dec 2023 19:13:33 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B5776D3 for ; Wed, 6 Dec 2023 16:13:38 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 51205C433C9; Thu, 7 Dec 2023 00:13:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1701908018; bh=jazxRliskDmzc1Drri43dvIbu3oMKjke07Ic+IoXtxs=; h=Date:To:From:Subject:From; b=rI95+Uc2od/4aErNzMwhLlmHG+sF9X/H2zzqIgSPpCLKZdNX3WGs146XOjnJAS52F yIH49NddSZQtyhzzel0+OV1PjPixMegkxa7E8/R7qZ1stAakhijG5gm/V8sHiTmSMb iXJmhz/JXveMVKkYb6W2sUSfxNcJc4FZynrZXDAM= Date: Wed, 06 Dec 2023 16:13:37 -0800 To: mm-commits@vger.kernel.org, sj@kernel.org, akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-hotfixes-stable] mm-damon-sysfs-schemes-add-timeout-for-update_schemes_tried_regions.patch removed from -mm tree Message-Id: <20231207001338.51205C433C9@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/damon/sysfs-schemes: add timeout for update_schemes_tried_regions has been removed from the -mm tree. Its filename was mm-damon-sysfs-schemes-add-timeout-for-update_schemes_tried_regions.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: SeongJae Park Subject: mm/damon/sysfs-schemes: add timeout for update_schemes_tried_regions Date: Fri, 24 Nov 2023 21:38:40 +0000 If a scheme is set to not applied to any monitoring target region for any reasons including the target access pattern, quota, filters, or watermarks, writing 'update_schemes_tried_regions' to 'state' DAMON sysfs file can indefinitely hang. Fix the case by implementing a timeout for the operation. The time limit is two apply intervals of each scheme. Link: https://lkml.kernel.org/r/20231124213840.39157-1-sj@kernel.org Fixes: 4d4e41b68299 ("mm/damon/sysfs-schemes: do not update tried regions more than one DAMON snapshot") Signed-off-by: SeongJae Park Signed-off-by: Andrew Morton --- mm/damon/sysfs-schemes.c | 49 ++++++++++++++++++++++++++++++++----- 1 file changed, 43 insertions(+), 6 deletions(-) --- a/mm/damon/sysfs-schemes.c~mm-damon-sysfs-schemes-add-timeout-for-update_schemes_tried_regions +++ a/mm/damon/sysfs-schemes.c @@ -139,6 +139,13 @@ static const struct kobj_type damon_sysf * damon_sysfs_before_damos_apply() understands the situation by showing the * 'finished' status and do nothing. * + * If DAMOS is not applied to any region due to any reasons including the + * access pattern, the watermarks, the quotas, and the filters, + * ->before_damos_apply() will not be called back. Until the situation is + * changed, the update will not be finished. To avoid this, + * damon_sysfs_after_sampling() set the status as 'finished' if more than two + * apply intervals of the scheme is passed while the state is 'idle'. + * * Finally, the tried regions request handling finisher function * (damon_sysfs_schemes_update_regions_stop()) unregisters the callbacks. */ @@ -154,6 +161,7 @@ struct damon_sysfs_scheme_regions { int nr_regions; unsigned long total_bytes; enum damos_sysfs_regions_upd_status upd_status; + unsigned long upd_timeout_jiffies; }; static struct damon_sysfs_scheme_regions * @@ -1854,7 +1862,9 @@ static int damon_sysfs_after_sampling(st for (i = 0; i < sysfs_schemes->nr; i++) { sysfs_regions = sysfs_schemes->schemes_arr[i]->tried_regions; if (sysfs_regions->upd_status == - DAMOS_TRIED_REGIONS_UPD_STARTED) + DAMOS_TRIED_REGIONS_UPD_STARTED || + time_after(jiffies, + sysfs_regions->upd_timeout_jiffies)) sysfs_regions->upd_status = DAMOS_TRIED_REGIONS_UPD_FINISHED; } @@ -1885,14 +1895,41 @@ int damon_sysfs_schemes_clear_regions( return 0; } +static struct damos *damos_sysfs_nth_scheme(int n, struct damon_ctx *ctx) +{ + struct damos *scheme; + int i = 0; + + damon_for_each_scheme(scheme, ctx) { + if (i == n) + return scheme; + i++; + } + return NULL; +} + static void damos_tried_regions_init_upd_status( - struct damon_sysfs_schemes *sysfs_schemes) + struct damon_sysfs_schemes *sysfs_schemes, + struct damon_ctx *ctx) { int i; + struct damos *scheme; + struct damon_sysfs_scheme_regions *sysfs_regions; - for (i = 0; i < sysfs_schemes->nr; i++) - sysfs_schemes->schemes_arr[i]->tried_regions->upd_status = - DAMOS_TRIED_REGIONS_UPD_IDLE; + for (i = 0; i < sysfs_schemes->nr; i++) { + sysfs_regions = sysfs_schemes->schemes_arr[i]->tried_regions; + scheme = damos_sysfs_nth_scheme(i, ctx); + if (!scheme) { + sysfs_regions->upd_status = + DAMOS_TRIED_REGIONS_UPD_FINISHED; + continue; + } + sysfs_regions->upd_status = DAMOS_TRIED_REGIONS_UPD_IDLE; + sysfs_regions->upd_timeout_jiffies = jiffies + + 2 * usecs_to_jiffies(scheme->apply_interval_us ? + scheme->apply_interval_us : + ctx->attrs.sample_interval); + } } /* Called from damon_sysfs_cmd_request_callback under damon_sysfs_lock */ @@ -1902,7 +1939,7 @@ int damon_sysfs_schemes_update_regions_s { damon_sysfs_schemes_clear_regions(sysfs_schemes, ctx); damon_sysfs_schemes_for_damos_callback = sysfs_schemes; - damos_tried_regions_init_upd_status(sysfs_schemes); + damos_tried_regions_init_upd_status(sysfs_schemes, ctx); damos_regions_upd_total_bytes_only = total_bytes_only; ctx->callback.before_damos_apply = damon_sysfs_before_damos_apply; ctx->callback.after_sampling = damon_sysfs_after_sampling; _ Patches currently in -mm which might be from sj@kernel.org are mm-damon-core-test-test-damon_split_region_ats-access-rate-copying.patch mm-damon-core-implement-goal-oriented-feedback-driven-quota-auto-tuning.patch mm-damon-core-implement-goal-oriented-feedback-driven-quota-auto-tuning-fix.patch mm-damon-sysfs-schemes-implement-files-for-scheme-quota-goals-setup.patch mm-damon-sysfs-schemes-commit-damos-quota-goals-user-input-to-damos.patch mm-damon-sysfs-schemes-implement-a-command-for-scheme-quota-goals-only-commit.patch mm-damon-core-test-add-a-unit-test-for-the-feedback-loop-algorithm.patch selftests-damon-test-quota-goals-directory.patch docs-mm-damon-design-document-damos-quota-auto-tuning.patch docs-abi-damon-document-damos-quota-goals.patch docs-admin-guide-mm-damon-usage-document-for-quota-goals.patch