From: Matthew Wilcox <willy@infradead.org>
To: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>,
akpm@linux-foundation.org, david@redhat.com, osalvador@suse.de,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 01/16] mm/page_alloc: ensure kswapd doesn't accidentally go to sleep
Date: Tue, 13 Sep 2022 08:58:55 +0100 [thread overview]
Message-ID: <YyA4Pz8hnnTsomUh@casper.infradead.org> (raw)
In-Reply-To: <ea96d35e-46ae-c168-3186-ddf58ad6806c@arm.com>
On Tue, Sep 13, 2022 at 12:32:50PM +0530, Anshuman Khandual wrote:
>
>
> On 9/9/22 14:54, Miaohe Lin wrote:
> > If ALLOC_KSWAPD is set, wake_all_kswapds() will be called to ensure
> > kswapd doesn't accidentally go to sleep. But when reserve_flags is
> > set, alloc_flags will be overwritten and ALLOC_KSWAPD is thus lost.
> > Preserve the ALLOC_KSWAPD flag in alloc_flags to ensure kswapd won't
> > go to sleep accidentally.
>
> Currently wake_all_kswapds() gets skipped subsequently if ALLOC_KSWAPD
> is lost, but this only happens when the 'retry:' loops is taken ?
Right, but see the comment:
/* Ensure kswapd doesn't accidentally go to sleep as long as we loop */
and that is not currently true. I think that was an inadvertent change.
Particularly since the changelog for 0a79cdad5eb2 says "No functional
change".
> >
> > Fixes: 0a79cdad5eb2 ("mm: use alloc_flags to record if kswapd can wake")
> > Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
> > ---
> > mm/page_alloc.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> > index ba5c9402a5cb..4b97a03fa2dd 100644
> > --- a/mm/page_alloc.c
> > +++ b/mm/page_alloc.c
> > @@ -5147,7 +5147,8 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
> >
> > reserve_flags = __gfp_pfmemalloc_flags(gfp_mask);
> > if (reserve_flags)
> > - alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, reserve_flags);
> > + alloc_flags = gfp_to_alloc_flags_cma(gfp_mask, reserve_flags) |
> > + (alloc_flags & ALLOC_KSWAPD);
> >
> > /*
> > * Reset the nodemask and zonelist iterators if memory policies can be
>
next prev parent reply other threads:[~2022-09-13 7:59 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-09 9:24 [PATCH 00/16] A few cleanup patches for mm Miaohe Lin
2022-09-09 9:24 ` [PATCH 01/16] mm/page_alloc: ensure kswapd doesn't accidentally go to sleep Miaohe Lin
2022-09-09 11:39 ` David Hildenbrand
2022-09-13 7:02 ` Anshuman Khandual
2022-09-13 7:58 ` Matthew Wilcox [this message]
2022-09-13 11:23 ` Anshuman Khandual
2022-09-15 4:34 ` Oscar Salvador
2022-09-09 9:24 ` [PATCH 02/16] mm/page_alloc: make zone_pcp_update() static Miaohe Lin
2022-09-09 11:26 ` David Hildenbrand
2022-09-13 7:58 ` Anshuman Khandual
2022-09-15 4:41 ` Oscar Salvador
2022-09-09 9:24 ` [PATCH 03/16] mm: remove obsolete macro NR_PCP_ORDER_MASK Miaohe Lin
2022-09-09 11:26 ` David Hildenbrand
2022-09-09 19:37 ` Matthew Wilcox
2022-09-13 3:14 ` Miaohe Lin
2022-09-13 8:03 ` Anshuman Khandual
2022-09-15 4:44 ` Oscar Salvador
2022-09-09 9:24 ` [PATCH 04/16] mm/page_alloc: remove obsolete comment in zone_statistics() Miaohe Lin
2022-09-09 11:27 ` David Hildenbrand
2022-09-13 8:15 ` Anshuman Khandual
2022-09-15 4:47 ` Oscar Salvador
2022-09-09 9:24 ` [PATCH 05/16] mm/page_alloc: add __init annotations to init_mem_debugging_and_hardening() Miaohe Lin
2022-09-09 11:27 ` David Hildenbrand
2022-09-13 8:20 ` Anshuman Khandual
2022-09-15 4:49 ` Oscar Salvador
2022-09-09 9:24 ` [PATCH 06/16] mm/page_alloc: fix freeing static percpu memory Miaohe Lin
2022-09-09 11:28 ` David Hildenbrand
2022-09-15 4:53 ` Oscar Salvador
2022-09-09 9:24 ` [PATCH 07/16] mm: remove obsolete pgdat_is_empty() Miaohe Lin
2022-09-09 11:28 ` David Hildenbrand
2022-09-13 8:43 ` Anshuman Khandual
2022-09-15 4:55 ` Oscar Salvador
2022-09-09 9:24 ` [PATCH 08/16] mm/page_alloc: add missing is_migrate_isolate() check in set_page_guard() Miaohe Lin
2022-09-09 11:31 ` David Hildenbrand
2022-09-13 6:51 ` Miaohe Lin
2022-09-15 7:26 ` Oscar Salvador
2022-09-15 8:11 ` Miaohe Lin
2022-09-09 9:24 ` [PATCH 09/16] mm/page_alloc: use local variable zone_idx directly Miaohe Lin
2022-09-09 11:31 ` David Hildenbrand
2022-09-13 8:49 ` Anshuman Khandual
2022-09-15 7:36 ` Oscar Salvador
2022-09-15 8:06 ` Miaohe Lin
2022-09-09 9:24 ` [PATCH 10/16] mm, memory_hotplug: remove obsolete generic_free_nodedata() Miaohe Lin
2022-09-09 11:32 ` David Hildenbrand
2022-09-13 8:57 ` Anshuman Khandual
2022-09-15 7:37 ` Oscar Salvador
2022-09-09 9:24 ` [PATCH 11/16] mm/page_alloc: make boot_nodestats static Miaohe Lin
2022-09-09 11:32 ` David Hildenbrand
2022-09-13 9:00 ` Anshuman Khandual
2022-09-15 7:38 ` Oscar Salvador
2022-09-09 9:24 ` [PATCH 12/16] mm/page_alloc: use helper macro SZ_1{K,M} Miaohe Lin
2022-09-09 11:34 ` David Hildenbrand
2022-09-09 19:44 ` Matthew Wilcox
2022-09-13 7:04 ` Miaohe Lin
2022-09-09 9:24 ` [PATCH 13/16] mm/page_alloc: init local variable buddy_pfn Miaohe Lin
2022-09-09 11:36 ` David Hildenbrand
2022-09-13 9:06 ` Anshuman Khandual
2022-09-15 7:42 ` Oscar Salvador
2022-09-09 9:24 ` [PATCH 14/16] mm/page_alloc: use costly_order in WARN_ON_ONCE_GFP() Miaohe Lin
2022-09-09 11:37 ` David Hildenbrand
2022-09-13 9:08 ` Anshuman Khandual
2022-09-15 7:45 ` Oscar Salvador
2022-09-09 9:24 ` [PATCH 15/16] mm/page_alloc: remove obsolete gfpflags_normal_context() Miaohe Lin
2022-09-09 11:37 ` David Hildenbrand
2022-09-13 11:12 ` Anshuman Khandual
2022-09-13 11:13 ` Anshuman Khandual
2022-09-15 7:48 ` Oscar Salvador
2022-09-09 9:24 ` [PATCH 16/16] mm/page_alloc: fix obsolete comment in deferred_pfn_valid() Miaohe Lin
2022-09-09 11:25 ` David Hildenbrand
2022-09-13 11:17 ` Anshuman Khandual
2022-09-15 7:50 ` Oscar Salvador
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