Attachment 217196 Details for Bug 248008 – keg_drain patch

[patch] keg_drain patch

diff (text/plain), 3.36 KB, created by Mark Johnston on 2020-08-13 15:19:29 UTC

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Creator: Mark Johnston

Created: 2020-08-13 15:19:29 UTC

Size: 3.36 KB

patch

obsolete

>commit aca984f242fecdfaa2baf66e55adccb5e2c31513
>Author: Mark Johnston <markjdb@gmail.com>
>Date:   Wed Aug 12 13:08:49 2020 -0400
>
>    uma: Respect uk_reserve in keg_drain().
>    
>    When we set a reserve of free items for a zone, we must take care to
>    avoid reclamining them.  The two existing uma_zone_reserve() callers in
>    the tree fail to set UMA_ZONE_NOFREE, which would have the desired
>    effect.  Moreover, _NOFREE is a fairly large hammer.
>    
>    Modify keg_drain() to simply respect the reserved pool.  For now we take
>    uk_reserve to be a per-NUMA domain quantity, since that's what existing
>    code does.
>    
>    While here remove an always-false uk_freef == NULL check, and make sure
>    that the keg_drain() KTR statement does not reference an uninitialized
>    variable.
>
>diff --git a/sys/vm/uma_core.c b/sys/vm/uma_core.c
>index 9d0786c1d754..5b3bcaf109a1 100644
>--- a/sys/vm/uma_core.c
>+++ b/sys/vm/uma_core.c
>@@ -1404,6 +1404,49 @@ keg_free_slab(uma_keg_t keg, uma_slab_t slab, int start)
> 	uma_total_dec(PAGE_SIZE * keg->uk_ppera);
> }
> 
>+static void
>+keg_drain_domain(uma_keg_t keg, int domain)
>+{
>+	struct slabhead freeslabs;
>+	uma_domain_t dom;
>+	uma_slab_t slab, tmp;
>+	int n, skip;
>+
>+	dom = &keg->uk_domain[domain];
>+	LIST_INIT(&freeslabs);
>+
>+	CTR4(KTR_UMA, "keg_drain %s(%p) domain %d free items: %u",
>+	    keg->uk_name, keg, i, dom->ud_free_items);
>+
>+	KEG_LOCK(keg, domain);
>+	if ((keg->uk_flags & UMA_ZFLAG_HASH) != 0) {
>+		skip = keg->uk_reserve;
>+		LIST_FOREACH(slab, &dom->ud_free_slab, us_link) {
>+			if (skip > 0)
>+				skip -= keg->uk_ppera;
>+			else
>+				UMA_HASH_REMOVE(&keg->uk_hash, slab);
>+		}
>+	}
>+	LIST_SWAP(&freeslabs, &dom->ud_free_slab, uma_slab, us_link);
>+	n = dom->ud_free_slabs;
>+	for (skip = keg->uk_reserve; skip > 0; skip -= keg->uk_ppera) {
>+		slab = LIST_FIRST(&freeslabs);
>+		if (slab == NULL)
>+			break;
>+		LIST_REMOVE(slab, us_link);
>+		LIST_INSERT_HEAD(&dom->ud_free_slab, slab, us_link);
>+		n--;
>+	}
>+	dom->ud_free_slabs -= n;
>+	dom->ud_free_items -= n * keg->uk_ipers;
>+	dom->ud_pages -= n * keg->uk_ppera;
>+	KEG_UNLOCK(keg, domain);
>+
>+	LIST_FOREACH_SAFE(slab, &freeslabs, us_link, tmp)
>+		keg_free_slab(keg, slab, keg->uk_ipers);
>+}
>+
> /*
>  * Frees pages from a keg back to the system.  This is done on demand from
>  * the pageout daemon.
>@@ -1413,35 +1456,12 @@ keg_free_slab(uma_keg_t keg, uma_slab_t slab, int start)
> static void
> keg_drain(uma_keg_t keg)
> {
>-	struct slabhead freeslabs;
>-	uma_domain_t dom;
>-	uma_slab_t slab, tmp;
>-	int i, n;
>+	int i;
> 
>-	if (keg->uk_flags & UMA_ZONE_NOFREE || keg->uk_freef == NULL)
>+	if ((keg->uk_flags & UMA_ZONE_NOFREE) != 0)
> 		return;
>-
>-	for (i = 0; i < vm_ndomains; i++) {
>-		CTR4(KTR_UMA, "keg_drain %s(%p) domain %d free items: %u",
>-		    keg->uk_name, keg, i, dom->ud_free_items);
>-		dom = &keg->uk_domain[i];
>-		LIST_INIT(&freeslabs);
>-
>-		KEG_LOCK(keg, i);
>-		if ((keg->uk_flags & UMA_ZFLAG_HASH) != 0) {
>-			LIST_FOREACH(slab, &dom->ud_free_slab, us_link)
>-				UMA_HASH_REMOVE(&keg->uk_hash, slab);
>-		}
>-		n = dom->ud_free_slabs;
>-		LIST_SWAP(&freeslabs, &dom->ud_free_slab, uma_slab, us_link);
>-		dom->ud_free_slabs = 0;
>-		dom->ud_free_items -= n * keg->uk_ipers;
>-		dom->ud_pages -= n * keg->uk_ppera;
>-		KEG_UNLOCK(keg, i);
>-
>-		LIST_FOREACH_SAFE(slab, &freeslabs, us_link, tmp)
>-			keg_free_slab(keg, slab, keg->uk_ipers);
>-	}
>+	for (i = 0; i < vm_ndomains; i++)
>+		keg_drain_domain(keg, i);
> }
> 
> static void

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