From 7c5d813b55a6229e18a0d948eaa38358f331dfbe Mon Sep 17 00:00:00 2001 From: Joel Fernandes Date: Mon, 12 Dec 2016 16:44:26 -0800 Subject: [PATCH] mm: add preempt points into __purge_vmap_area_lazy() Use cond_resched_lock to avoid holding the vmap_area_lock for a potentially long time and thus creating bad latencies for various workloads. Change-Id: I36eb4d8dbd6604f52e5c463373a9754847a44bc2 [hch: split from a larger patch by Joel, wrote the crappy changelog] Link: http://lkml.kernel.org/r/1479474236-4139-11-git-send-email-hch@lst.de Signed-off-by: Joel Fernandes Signed-off-by: Christoph Hellwig Tested-by: Jisheng Zhang Cc: Andrey Ryabinin Cc: Chris Wilson Cc: John Dias Cc: Thomas Gleixner Cc: "H. Peter Anvin" Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Git-commit: 763b218ddfaf56761c19923beb7e16656f66ec62 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Vinayak Menon --- mm/vmalloc.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 30818930331f..b24be2a7f456 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -656,7 +656,7 @@ static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end) struct llist_node *valist; struct vmap_area *va; struct vmap_area *n_va; - int nr = 0; + bool do_free = false; lockdep_assert_held(&vmap_purge_lock); @@ -666,18 +666,22 @@ static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end) start = va->va_start; if (va->va_end > end) end = va->va_end; - nr += (va->va_end - va->va_start) >> PAGE_SHIFT; + do_free = true; } - if (!nr) + if (!do_free) return false; - atomic_sub(nr, &vmap_lazy_nr); flush_tlb_kernel_range(start, end); spin_lock(&vmap_area_lock); - llist_for_each_entry_safe(va, n_va, valist, purge_list) + llist_for_each_entry_safe(va, n_va, valist, purge_list) { + int nr = (va->va_end - va->va_start) >> PAGE_SHIFT; + __free_vmap_area(va); + atomic_sub(nr, &vmap_lazy_nr); + cond_resched_lock(&vmap_area_lock); + } spin_unlock(&vmap_area_lock); return true; }