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mm: add preempt points into __purge_vmap_area_lazy()

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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@lst.de
Signed-off-by: Joel Fernandes <joelaf@google.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Jisheng Zhang <jszhang@marvell.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: John Dias <joaodias@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Joel Fernandes 2016-12-12 16:44:26 -08:00 committed by Linus Torvalds
parent f9e0997767
commit 763b218ddf
1 changed files with 9 additions and 5 deletions
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14
mm/vmalloc.c
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@ -628,7 +628,7 @@ 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);
@ -638,18 +638,22 @@ 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;
}