The patch titled
Subject: mm/page_alloc.c: don't show protection in zone's ->lowmem_reserve[] for empty zone
has been added to the -mm mm-unstable branch. Its filename is
mm-page_allocc-dont-show-protection-in-zones-lowmem_reserve-for-empty-zone.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-page_allocc-dont-show-protection-in-zones-lowmem_reserve-for-empty-zone.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: Baoquan He <bhe@xxxxxxxxxx>
Subject: mm/page_alloc.c: don't show protection in zone's ->lowmem_reserve[] for empty zone
Date: Tue, 26 Mar 2024 14:11:32 +0800
On one node, for lower zone's ->lowmem_reserve[], it will show how much
memory is reserved in this lower zone to avoid excessive page allocation
from the relevant higher zone's fallback allocation.
However, currently lower zone's lowmem_reserve[] element will be filled
even though the relevant higher zone is empty. That doesnt' make sense
and can cause confusion.
E.g on node 0 of one system as below, it has zone
DMA/DMA32/NORMAL/MOVABLE/DEVICE, among them zone MOVABLE/DEVICE are the
highest and both are empty. In zone DMA/DMA32's protection array, we can
see that it has value for zone MOVABLE and DEVICE.
Node 0, zone DMA
......
pages free 2816
boost 0
min 7
low 10
high 13
spanned 4095
present 3998
managed 3840
cma 0
protection: (0, 1582, 23716, 23716, 23716)
......
Node 0, zone DMA32
pages free 403269
boost 0
min 753
low 1158
high 1563
spanned 1044480
present 487039
managed 405070
cma 0
protection: (0, 0, 22134, 22134, 22134)
......
Node 0, zone Normal
pages free 5423879
boost 0
min 10539
low 16205
high 21871
spanned 5767168
present 5767168
managed 5666438
cma 0
protection: (0, 0, 0, 0, 0)
......
Node 0, zone Movable
pages free 0
boost 0
min 32
low 32
high 32
spanned 0
present 0
managed 0
cma 0
protection: (0, 0, 0, 0, 0)
Node 0, zone Device
pages free 0
boost 0
min 0
low 0
high 0
spanned 0
present 0
managed 0
cma 0
protection: (0, 0, 0, 0, 0)
Here, clear out the element value in lower zone's ->lowmem_reserve[] if the
relevant higher zone is empty.
And also replace space with tab in _deferred_grow_zone()
Link: https://lkml.kernel.org/r/20240326061134.1055295-7-bhe@xxxxxxxxxx
Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: "Mike Rapoport (IBM)" <rppt@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/mm/page_alloc.c~mm-page_allocc-dont-show-protection-in-zones-lowmem_reserve-for-empty-zone
+++ a/mm/page_alloc.c
@@ -315,7 +315,7 @@ static inline bool deferred_pages_enable
static bool __ref
_deferred_grow_zone(struct zone *zone, unsigned int order)
{
- return deferred_grow_zone(zone, order);
+ return deferred_grow_zone(zone, order);
}
#else
static inline bool deferred_pages_enabled(void)
@@ -5911,10 +5911,11 @@ static void setup_per_zone_lowmem_reserv
for (j = i + 1; j < MAX_NR_ZONES; j++) {
struct zone *upper_zone = &pgdat->node_zones[j];
+ bool empty = !zone_managed_pages(upper_zone);
managed_pages += zone_managed_pages(upper_zone);
- if (clear)
+ if (clear || empty)
zone->lowmem_reserve[j] = 0;
else
zone->lowmem_reserve[j] = managed_pages / ratio;
_
Patches currently in -mm which might be from bhe@xxxxxxxxxx are
mm-vmallocc-optimize-to-reduce-arguments-of-alloc_vmap_area.patch
x86-remove-unneeded-memblock_find_dma_reserve.patch
mm-mm_initc-remove-the-useless-dma_reserve.patch
mm-mm_initc-add-new-function-calc_nr_all_pages.patch
mm-mm_initc-remove-meaningless-calculation-of-zone-managed_pages-in-free_area_init_core.patch
mm-mm_initc-remove-unneeded-calc_memmap_size.patch
mm-mm_initc-remove-arch_reserved_kernel_pages.patch
mm-move-array-mem_section-init-code-out-of-memory_present.patch
mm-init-remove-the-unnecessary-special-treatment-for-memory-less-node.patch
mm-make-__absent_pages_in_range-as-static.patch
mm-page_allocc-remove-unneeded-codes-in-numa-version-of-build_zonelists.patch
mm-mm_initc-remove-the-outdated-code-comment-above-deferred_grow_zone.patch
mm-page_allocc-dont-show-protection-in-zones-lowmem_reserve-for-empty-zone.patch
mm-page_allocc-change-the-array-length-to-migrate_pcptypes.patch
