From: Joel Fernandes <joelaf@xxxxxxxxxx> Subject: 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. [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@xxxxxx Signed-off-by: Joel Fernandes <joelaf@xxxxxxxxxx> Signed-off-by: Christoph Hellwig <hch@xxxxxx> Tested-by: Jisheng Zhang <jszhang@xxxxxxxxxxx> Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Cc: John Dias <joaodias@xxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/vmalloc.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff -puN mm/vmalloc.c~mm-add-preempt-points-into-__purge_vmap_area_lazy mm/vmalloc.c --- a/mm/vmalloc.c~mm-add-preempt-points-into-__purge_vmap_area_lazy +++ a/mm/vmalloc.c @@ -628,7 +628,7 @@ static bool __purge_vmap_area_lazy(unsig 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); @@ -638,18 +638,22 @@ static bool __purge_vmap_area_lazy(unsig 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; } _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
