From: Ye Liu Date: Fri, 18 Jul 2025 02:41:32 +0000 (+0800) Subject: mm: replace (20 - PAGE_SHIFT) with common macros for pages<->MB conversion X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=ddf8b129509a259832f9f41e51b4d32118e488e6;p=users%2Fjedix%2Flinux-maple.git mm: replace (20 - PAGE_SHIFT) with common macros for pages<->MB conversion Replace repeated (20 - PAGE_SHIFT) calculations with standard macros: - MB_TO_PAGES(mb) converts MB to page count - PAGES_TO_MB(pages) converts pages to MB No functional change. Link: https://lkml.kernel.org/r/20250718024134.1304745-1-ye.liu@linux.dev Signed-off-by: Ye Liu Acked-by: Zi Yan Reviewed-by: Lorenzo Stoakes Reviewed-by: Dev Jain Acked-by: David Hildenbrand Acked-by: Chris Li Cc: Baolin Wang Cc: Baoquan He Cc: Barry Song Cc: Ben Segall Cc: Boqun Feng Cc: Davidlohr Bueso Cc: Dietmar Eggemann Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Josh Triplett Cc: Juri Lelli Cc: Kairui Song Cc: Kemeng Shi Cc: Lai jiangshan Cc: Liam Howlett Cc: Mariano Pache Cc: Mathieu Desnoyers Cc: Mel Gorman Cc: Michal Hocko Cc: Mike Rapoport Cc: Neeraj Upadhyay Cc: Nhat Pham Cc: "Paul E . McKenney" Cc: Peter Zijlstra Cc: Ryan Roberts Cc: Steven Rostedt Cc: Suren Baghdasaryan Cc: "Uladzislau Rezki (Sony)" Cc: Valentin Schneider Cc: Vincent Guittot Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- diff --git a/include/linux/mm.h b/include/linux/mm.h index 1ae97a0b8ec7..b626d1bacef5 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -69,6 +69,15 @@ static inline void totalram_pages_add(long count) extern void * high_memory; +/* + * Convert between pages and MB + * 20 is the shift for 1MB (2^20 = 1MB) + * PAGE_SHIFT is the shift for page size (e.g., 12 for 4KB pages) + * So (20 - PAGE_SHIFT) converts between pages and MB + */ +#define PAGES_TO_MB(pages) ((pages) >> (20 - PAGE_SHIFT)) +#define MB_TO_PAGES(mb) ((mb) << (20 - PAGE_SHIFT)) + #ifdef CONFIG_SYSCTL extern int sysctl_legacy_va_layout; #else diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c index b521d0455992..7484d8ad5767 100644 --- a/kernel/rcu/rcuscale.c +++ b/kernel/rcu/rcuscale.c @@ -796,7 +796,7 @@ kfree_scale_thread(void *arg) pr_alert("Total time taken by all kfree'ers: %llu ns, loops: %d, batches: %ld, memory footprint: %lldMB\n", (unsigned long long)(end_time - start_time), kfree_loops, rcuscale_seq_diff(b_rcu_gp_test_finished, b_rcu_gp_test_started), - (mem_begin - mem_during) >> (20 - PAGE_SHIFT)); + PAGES_TO_MB(mem_begin - mem_during)); if (shutdown) { smp_mb(); /* Assign before wake. */ diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 82c8d804c54c..e256793b9a08 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1495,7 +1495,7 @@ static unsigned int task_nr_scan_windows(struct task_struct *p) * by the PTE scanner and NUMA hinting faults should be trapped based * on resident pages */ - nr_scan_pages = sysctl_numa_balancing_scan_size << (20 - PAGE_SHIFT); + nr_scan_pages = MB_TO_PAGES(sysctl_numa_balancing_scan_size); rss = get_mm_rss(p->mm); if (!rss) rss = nr_scan_pages; @@ -1934,8 +1934,7 @@ bool should_numa_migrate_memory(struct task_struct *p, struct folio *folio, } def_th = sysctl_numa_balancing_hot_threshold; - rate_limit = sysctl_numa_balancing_promote_rate_limit << \ - (20 - PAGE_SHIFT); + rate_limit = MB_TO_PAGES(sysctl_numa_balancing_promote_rate_limit); numa_promotion_adjust_threshold(pgdat, rate_limit, def_th); th = pgdat->nbp_threshold ? : def_th; diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 783904d8c5ef..e4d578e6121c 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -510,7 +510,7 @@ static void wb_update_bandwidth_workfn(struct work_struct *work) /* * Initial write bandwidth: 100 MB/s */ -#define INIT_BW (100 << (20 - PAGE_SHIFT)) +#define INIT_BW MB_TO_PAGES(100) static int wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi, gfp_t gfp) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 9c38a95e9f09..2b4ea5a2ce7d 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -911,7 +911,7 @@ static int __init hugepage_init(void) * where the extra memory used could hurt more than TLB overhead * is likely to save. The admin can still enable it through /sys. */ - if (totalram_pages() < (512 << (20 - PAGE_SHIFT))) { + if (totalram_pages() < MB_TO_PAGES(512)) { transparent_hugepage_flags = 0; return 0; } diff --git a/mm/swap.c b/mm/swap.c index 881e53b2877e..60e7b509807b 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -1101,7 +1101,7 @@ static const struct ctl_table swap_sysctl_table[] = { */ void __init swap_setup(void) { - unsigned long megs = totalram_pages() >> (20 - PAGE_SHIFT); + unsigned long megs = PAGES_TO_MB(totalram_pages()); /* Use a smaller cluster for small-memory machines */ if (megs < 16)