From: Baoquan He <bhe@redhat.com> To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, x86@kernel.org, linuxppc-dev@lists.ozlabs.org, akpm@linux-foundation.org, rppt@kernel.org, Baoquan He <bhe@redhat.com> Subject: [PATCH 4/6] mm/mm_init.c: remove meaningless calculation of zone->managed_pages in free_area_init_core() Date: Mon, 18 Mar 2024 22:21:36 +0800 [thread overview] Message-ID: <20240318142138.783350-5-bhe@redhat.com> (raw) In-Reply-To: <20240318142138.783350-1-bhe@redhat.com> Currently, in free_area_init_core(), when initialize zone's field, a rough value is set to zone->managed_pages. That value is calculated by (zone->present_pages - memmap_pages). In the meantime, add the value to nr_all_pages and nr_kernel_pages which represent all free pages of system (only low memory or including HIGHMEM memory separately). Both of them are gonna be used in alloc_large_system_hash(). However, the rough calculation and setting of zone->managed_pages is meaningless because a) memmap pages are allocated on units of node in sparse_init() or alloc_node_mem_map(pgdat); The simple (zone->present_pages - memmap_pages) is too rough to make sense for zone; b) the set zone->managed_pages will be zeroed out and reset with acutal value in mem_init() via memblock_free_all(). Before the resetting, no buddy allocation request is issued. Here, remove the meaningless and complicated calculation of (zone->present_pages - memmap_pages), directly set zone->present_pages to zone->managed_pages. It will be adjusted in mem_init(). And also remove the assignment of nr_all_pages and nr_kernel_pages in free_area_init_core(). Instead, call the newly added calc_nr_kernel_pages() to count up all free but not reserved memory in memblock and assign to nr_all_pages and nr_kernel_pages. The counting excludes memmap_pages, and other kernel used data, which is more accurate than old way and simpler, and can also cover the ppc required arch_reserved_kernel_pages() case. Signed-off-by: Baoquan He <bhe@redhat.com> --- mm/mm_init.c | 38 ++++++-------------------------------- 1 file changed, 6 insertions(+), 32 deletions(-) diff --git a/mm/mm_init.c b/mm/mm_init.c index c57a7fc97a16..55a2b886b7a6 100644 --- a/mm/mm_init.c +++ b/mm/mm_init.c @@ -1584,41 +1584,14 @@ static void __init free_area_init_core(struct pglist_data *pgdat) for (j = 0; j < MAX_NR_ZONES; j++) { struct zone *zone = pgdat->node_zones + j; - unsigned long size, freesize, memmap_pages; - - size = zone->spanned_pages; - freesize = zone->present_pages; - - /* - * Adjust freesize so that it accounts for how much memory - * is used by this zone for memmap. This affects the watermark - * and per-cpu initialisations - */ - memmap_pages = calc_memmap_size(size, freesize); - if (!is_highmem_idx(j)) { - if (freesize >= memmap_pages) { - freesize -= memmap_pages; - if (memmap_pages) - pr_debug(" %s zone: %lu pages used for memmap\n", - zone_names[j], memmap_pages); - } else - pr_warn(" %s zone: %lu memmap pages exceeds freesize %lu\n", - zone_names[j], memmap_pages, freesize); - } - - if (!is_highmem_idx(j)) - nr_kernel_pages += freesize; - /* Charge for highmem memmap if there are enough kernel pages */ - else if (nr_kernel_pages > memmap_pages * 2) - nr_kernel_pages -= memmap_pages; - nr_all_pages += freesize; + unsigned long size = zone->spanned_pages; /* - * Set an approximate value for lowmem here, it will be adjusted - * when the bootmem allocator frees pages into the buddy system. - * And all highmem pages will be managed by the buddy system. + * Set the zone->managed_pages as zone->present_pages roughly, it + * be zeroed out and reset when memblock allocator frees pages into + * buddy system. */ - zone_init_internals(zone, j, nid, freesize); + zone_init_internals(zone, j, nid, zone->present_pages); if (!size) continue; @@ -1915,6 +1888,7 @@ void __init free_area_init(unsigned long *max_zone_pfn) check_for_memory(pgdat); } + calc_nr_kernel_pages(); memmap_init(); /* disable hash distribution for systems with a single node */ -- 2.41.0
WARNING: multiple messages have this Message-ID (diff)
From: Baoquan He <bhe@redhat.com> To: linux-mm@kvack.org Cc: Baoquan He <bhe@redhat.com>, x86@kernel.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org, rppt@kernel.org Subject: [PATCH 4/6] mm/mm_init.c: remove meaningless calculation of zone->managed_pages in free_area_init_core() Date: Mon, 18 Mar 2024 22:21:36 +0800 [thread overview] Message-ID: <20240318142138.783350-5-bhe@redhat.com> (raw) In-Reply-To: <20240318142138.783350-1-bhe@redhat.com> Currently, in free_area_init_core(), when initialize zone's field, a rough value is set to zone->managed_pages. That value is calculated by (zone->present_pages - memmap_pages). In the meantime, add the value to nr_all_pages and nr_kernel_pages which represent all free pages of system (only low memory or including HIGHMEM memory separately). Both of them are gonna be used in alloc_large_system_hash(). However, the rough calculation and setting of zone->managed_pages is meaningless because a) memmap pages are allocated on units of node in sparse_init() or alloc_node_mem_map(pgdat); The simple (zone->present_pages - memmap_pages) is too rough to make sense for zone; b) the set zone->managed_pages will be zeroed out and reset with acutal value in mem_init() via memblock_free_all(). Before the resetting, no buddy allocation request is issued. Here, remove the meaningless and complicated calculation of (zone->present_pages - memmap_pages), directly set zone->present_pages to zone->managed_pages. It will be adjusted in mem_init(). And also remove the assignment of nr_all_pages and nr_kernel_pages in free_area_init_core(). Instead, call the newly added calc_nr_kernel_pages() to count up all free but not reserved memory in memblock and assign to nr_all_pages and nr_kernel_pages. The counting excludes memmap_pages, and other kernel used data, which is more accurate than old way and simpler, and can also cover the ppc required arch_reserved_kernel_pages() case. Signed-off-by: Baoquan He <bhe@redhat.com> --- mm/mm_init.c | 38 ++++++-------------------------------- 1 file changed, 6 insertions(+), 32 deletions(-) diff --git a/mm/mm_init.c b/mm/mm_init.c index c57a7fc97a16..55a2b886b7a6 100644 --- a/mm/mm_init.c +++ b/mm/mm_init.c @@ -1584,41 +1584,14 @@ static void __init free_area_init_core(struct pglist_data *pgdat) for (j = 0; j < MAX_NR_ZONES; j++) { struct zone *zone = pgdat->node_zones + j; - unsigned long size, freesize, memmap_pages; - - size = zone->spanned_pages; - freesize = zone->present_pages; - - /* - * Adjust freesize so that it accounts for how much memory - * is used by this zone for memmap. This affects the watermark - * and per-cpu initialisations - */ - memmap_pages = calc_memmap_size(size, freesize); - if (!is_highmem_idx(j)) { - if (freesize >= memmap_pages) { - freesize -= memmap_pages; - if (memmap_pages) - pr_debug(" %s zone: %lu pages used for memmap\n", - zone_names[j], memmap_pages); - } else - pr_warn(" %s zone: %lu memmap pages exceeds freesize %lu\n", - zone_names[j], memmap_pages, freesize); - } - - if (!is_highmem_idx(j)) - nr_kernel_pages += freesize; - /* Charge for highmem memmap if there are enough kernel pages */ - else if (nr_kernel_pages > memmap_pages * 2) - nr_kernel_pages -= memmap_pages; - nr_all_pages += freesize; + unsigned long size = zone->spanned_pages; /* - * Set an approximate value for lowmem here, it will be adjusted - * when the bootmem allocator frees pages into the buddy system. - * And all highmem pages will be managed by the buddy system. + * Set the zone->managed_pages as zone->present_pages roughly, it + * be zeroed out and reset when memblock allocator frees pages into + * buddy system. */ - zone_init_internals(zone, j, nid, freesize); + zone_init_internals(zone, j, nid, zone->present_pages); if (!size) continue; @@ -1915,6 +1888,7 @@ void __init free_area_init(unsigned long *max_zone_pfn) check_for_memory(pgdat); } + calc_nr_kernel_pages(); memmap_init(); /* disable hash distribution for systems with a single node */ -- 2.41.0
next prev parent reply other threads:[~2024-03-18 14:22 UTC|newest] Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-03-18 14:21 [PATCH 0/6] mm/mm_init.c: refactor free_area_init_core() Baoquan He 2024-03-18 14:21 ` Baoquan He 2024-03-18 14:21 ` [PATCH 1/6] mm/mm_init.c: remove the useless dma_reserve Baoquan He 2024-03-18 14:21 ` Baoquan He 2024-03-18 14:21 ` [PATCH 2/6] x86: remove memblock_find_dma_reserve() Baoquan He 2024-03-18 14:21 ` Baoquan He 2024-03-19 15:49 ` Mike Rapoport 2024-03-19 15:49 ` Mike Rapoport 2024-03-20 7:52 ` Baoquan He 2024-03-20 7:52 ` Baoquan He 2024-03-20 9:36 ` Mike Rapoport 2024-03-20 9:36 ` Mike Rapoport 2024-03-20 13:14 ` Baoquan He 2024-03-20 13:14 ` Baoquan He 2024-03-18 14:21 ` [PATCH 3/6] mm/mm_init.c: add new function calc_nr_kernel_pages() Baoquan He 2024-03-18 14:21 ` Baoquan He 2024-03-18 14:21 ` Baoquan He [this message] 2024-03-18 14:21 ` [PATCH 4/6] mm/mm_init.c: remove meaningless calculation of zone->managed_pages in free_area_init_core() Baoquan He 2024-03-19 16:17 ` Mike Rapoport 2024-03-19 16:17 ` Mike Rapoport 2024-03-20 8:18 ` Baoquan He 2024-03-20 8:18 ` Baoquan He 2024-03-20 8:47 ` Baoquan He 2024-03-20 8:47 ` Baoquan He 2024-03-18 14:21 ` [PATCH 5/6] mm/mm_init.c: remove unneeded calc_memmap_size() Baoquan He 2024-03-18 14:21 ` Baoquan He 2024-03-18 14:21 ` [PATCH 6/6] mm/mm_init.c: remove arch_reserved_kernel_pages() Baoquan He 2024-03-18 14:21 ` Baoquan He
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