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 310C0C3DA78 for ; Sat, 14 Jan 2023 04:40:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229874AbjANEkw (ORCPT ); Fri, 13 Jan 2023 23:40:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52240 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229570AbjANEkk (ORCPT ); Fri, 13 Jan 2023 23:40:40 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9BE19AF for ; Fri, 13 Jan 2023 20:40:39 -0800 (PST) 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 4320CB822C0 for ; Sat, 14 Jan 2023 04:40:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D1AF7C433D2; Sat, 14 Jan 2023 04:40:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1673671236; bh=9TRJtua45vqv3Z/rBSg1grnVK8eRCGgB3o6w9sE1PU0=; h=Date:To:From:Subject:From; b=hQpofd36KKrmjN8upAq8aQCLaBXYot5qWfYnlY7O2wFE8T6MqjJ4dxtRneYhwZMbT gLwDku4cq4Jc7d74YgU7/BIroABgxQlCbroN14GsgEJdWhVOL1+YSTdr0U7XL4bz8v VT2nkvEqeTw3QeT8Kf0M1lwo8UsjDUFSCIgXN2sE= Date: Fri, 13 Jan 2023 20:40:36 -0800 To: mm-commits@vger.kernel.org, willy@infradead.org, vbabka@suse.cz, thierry.reding@gmail.com, neilb@suse.de, mhocko@suse.com, mgorman@techsingularity.net, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-page_alloc-explicitly-define-what-alloc-flags-deplete-min-reserves.patch added to mm-unstable branch Message-Id: <20230114044036.D1AF7C433D2@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm/page_alloc: explicitly define what alloc flags deplete min reserves has been added to the -mm mm-unstable branch. Its filename is mm-page_alloc-explicitly-define-what-alloc-flags-deplete-min-reserves.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-page_alloc-explicitly-define-what-alloc-flags-deplete-min-reserves.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Mel Gorman Subject: mm/page_alloc: explicitly define what alloc flags deplete min reserves Date: Fri, 13 Jan 2023 11:12:15 +0000 As there are more ALLOC_ flags that affect reserves, define what flags affect reserves and clarify the effect of each flag. Link: https://lkml.kernel.org/r/20230113111217.14134-5-mgorman@techsingularity.net Signed-off-by: Mel Gorman Acked-by: Vlastimil Babka Acked-by: Michal Hocko Cc: Matthew Wilcox Cc: NeilBrown Cc: Thierry Reding Signed-off-by: Andrew Morton --- --- a/mm/internal.h~mm-page_alloc-explicitly-define-what-alloc-flags-deplete-min-reserves +++ a/mm/internal.h @@ -792,6 +792,9 @@ unsigned int reclaim_clean_pages_from_li #define ALLOC_HIGHATOMIC 0x200 /* Allows access to MIGRATE_HIGHATOMIC */ #define ALLOC_KSWAPD 0x800 /* allow waking of kswapd, __GFP_KSWAPD_RECLAIM set */ +/* Flags that allow allocations below the min watermark. */ +#define ALLOC_RESERVES (ALLOC_HARDER|ALLOC_MIN_RESERVE|ALLOC_HIGHATOMIC|ALLOC_OOM) + enum ttu_flags; struct tlbflush_unmap_batch; --- a/mm/page_alloc.c~mm-page_alloc-explicitly-define-what-alloc-flags-deplete-min-reserves +++ a/mm/page_alloc.c @@ -3967,15 +3967,14 @@ ALLOW_ERROR_INJECTION(should_fail_alloc_ static inline long __zone_watermark_unusable_free(struct zone *z, unsigned int order, unsigned int alloc_flags) { - const bool alloc_harder = (alloc_flags & (ALLOC_HARDER|ALLOC_OOM)); long unusable_free = (1 << order) - 1; /* - * If the caller does not have rights to ALLOC_HARDER then subtract - * the high-atomic reserves. This will over-estimate the size of the - * atomic reserve but it avoids a search. + * If the caller does not have rights to reserves below the min + * watermark then subtract the high-atomic reserves. This will + * over-estimate the size of the atomic reserve but it avoids a search. */ - if (likely(!alloc_harder)) + if (likely(!(alloc_flags & ALLOC_RESERVES))) unusable_free += z->nr_reserved_highatomic; #ifdef CONFIG_CMA @@ -3999,25 +3998,36 @@ bool __zone_watermark_ok(struct zone *z, { long min = mark; int o; - const bool alloc_harder = (alloc_flags & (ALLOC_HARDER|ALLOC_OOM)); /* free_pages may go negative - that's OK */ free_pages -= __zone_watermark_unusable_free(z, order, alloc_flags); - if (alloc_flags & ALLOC_MIN_RESERVE) - min -= min / 2; + if (unlikely(alloc_flags & ALLOC_RESERVES)) { + /* + * __GFP_HIGH allows access to 50% of the min reserve as well + * as OOM. + */ + if (alloc_flags & ALLOC_MIN_RESERVE) + min -= min / 2; + + /* + * Non-blocking allocations can access some of the reserve + * with more access if also __GFP_HIGH. The reasoning is that + * a non-blocking caller may incur a more severe penalty + * if it cannot get memory quickly, particularly if it's + * also __GFP_HIGH. + */ + if (alloc_flags & ALLOC_HARDER) + min -= min / 4; - if (unlikely(alloc_harder)) { /* - * OOM victims can try even harder than normal ALLOC_HARDER + * OOM victims can try even harder than the normal reserve * users on the grounds that it's definitely going to be in * the exit path shortly and free memory. Any allocation it * makes during the free path will be small and short-lived. */ if (alloc_flags & ALLOC_OOM) min -= min / 2; - else - min -= min / 4; } /* _ Patches currently in -mm which might be from mgorman@techsingularity.net are mm-page_alloc-rename-alloc_high-to-alloc_min_reserve.patch mm-page_alloc-treat-rt-tasks-similar-to-__gfp_high.patch mm-page_alloc-explicitly-record-high-order-atomic-allocations-in-alloc_flags.patch mm-page_alloc-explicitly-define-what-alloc-flags-deplete-min-reserves.patch mm-page_alloc-explicitly-define-how-__gfp_high-non-blocking-allocations-accesses-reserves.patch