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Commit dceac2f0 authored by Sanjay Dwivedi's avatar Sanjay Dwivedi Committed by Gerrit - the friendly Code Review server
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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: default avatarJoel Fernandes <joelaf@google.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Tested-by: default avatarJisheng 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Git-commit: 763b218ddfaf56761c19923beb7e16656f66ec62
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: default avatarVinayak Menon <vinmenon@codeaurora.org>
Signed-off-by: default avatarSanjay Dwivedi <sanjaykd@codeaurora.org>
parent 36e92370

mm/vmalloc.c

+9 −8
Original line number Original line Diff line number Diff line
@@ -651,7 +651,7 @@ static void __purge_vmap_area_lazy(unsigned long *start, unsigned long *end, 
	LIST_HEAD(valist);

	LIST_HEAD(valist);

	struct vmap_area *va;

	struct vmap_area *va;

	struct vmap_area *n_va;

	struct vmap_area *n_va;

	int nr = 0;

	bool do_free = false;





	/*

	/*

	 * If sync is 0 but force_flush is 1, we'll go sync anyway but callers

	 * If sync is 0 but force_flush is 1, we'll go sync anyway but callers
@@ -674,7 +674,7 @@ static void __purge_vmap_area_lazy(unsigned long *start, unsigned long *end, 
				*start = va->va_start;

				*start = va->va_start;

			if (va->va_end > *end)

			if (va->va_end > *end)

				*end = va->va_end;

				*end = va->va_end;

			nr += (va->va_end - va->va_start) >> PAGE_SHIFT;

			do_free = true;

			list_add_tail(&va->purge_list, &valist);

			list_add_tail(&va->purge_list, &valist);

			va->flags |= VM_LAZY_FREEING;

			va->flags |= VM_LAZY_FREEING;

			va->flags &= ~VM_LAZY_FREE;

			va->flags &= ~VM_LAZY_FREE;
@@ -682,16 +682,17 @@ static void __purge_vmap_area_lazy(unsigned long *start, unsigned long *end, 
	}

	}

	rcu_read_unlock();

	rcu_read_unlock();





	if (nr)

	if (do_free || force_flush)

		atomic_sub(nr, &vmap_lazy_nr);



	if (nr || force_flush)

		flush_tlb_kernel_range(*start, *end);

		flush_tlb_kernel_range(*start, *end);





	if (nr) {

	if (do_free) {

		spin_lock(&vmap_area_lock);

		spin_lock(&vmap_area_lock);

		list_for_each_entry_safe(va, n_va, &valist, purge_list)

		list_for_each_entry_safe(va, n_va, &valist, purge_list) {

			int nr = (va->va_end - va->va_start) >> PAGE_SHIFT;

			__free_vmap_area(va);

			__free_vmap_area(va);

			atomic_sub(nr, &vmap_lazy_nr);

			cond_resched_lock(&vmap_area_lock);

		}

		spin_unlock(&vmap_area_lock);

		spin_unlock(&vmap_area_lock);

	}

	}

	spin_unlock(&purge_lock);

	spin_unlock(&purge_lock);