From 6030fd5fd1f7baaac3661a5301cc7838d4e3b7f6 Mon Sep 17 00:00:00 2001 From: "Uladzislau Rezki (Sony)" Date: Tue, 18 Oct 2022 20:10:51 +0200 Subject: [PATCH] mm: vmalloc: use trace_purge_vmap_area_lazy event This is for debug purposes and is called when all outstanding areas are removed back to the vmap space. It gives some extra information about: - a start:end range where set of vmap ares were freed; - a number of purged areas which were backed off. [urezki@gmail.com: simplify return boolean expression] Link: https://lkml.kernel.org/r/20221020125247.5053-1-urezki@gmail.com Link: https://lkml.kernel.org/r/20221018181053.434508-6-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) Reviewed-by: Steven Rostedt (Google) Reviewed-by: Christoph Hellwig Cc: Matthew Wilcox (Oracle) Cc: Nicholas Piggin Cc: Oleksiy Avramchenko Signed-off-by: Andrew Morton --- mm/vmalloc.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 849563d334fb..1b1205ade1cf 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1730,6 +1730,7 @@ static void purge_fragmented_blocks_allcpus(void); static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end) { unsigned long resched_threshold; + unsigned int num_purged_areas = 0; struct list_head local_purge_list; struct vmap_area *va, *n_va; @@ -1741,7 +1742,7 @@ static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end) spin_unlock(&purge_vmap_area_lock); if (unlikely(list_empty(&local_purge_list))) - return false; + goto out; start = min(start, list_first_entry(&local_purge_list, @@ -1776,12 +1777,16 @@ static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end) va->va_start, va->va_end); atomic_long_sub(nr, &vmap_lazy_nr); + num_purged_areas++; if (atomic_long_read(&vmap_lazy_nr) < resched_threshold) cond_resched_lock(&free_vmap_area_lock); } spin_unlock(&free_vmap_area_lock); - return true; + +out: + trace_purge_vmap_area_lazy(start, end, num_purged_areas); + return num_purged_areas > 0; } /*