From 640c2ff8ae9bdbad91aa25094123bb97e5a92bbf Mon Sep 17 00:00:00 2001 From: Don Morris Date: Thu, 20 May 2021 10:54:38 -0400 Subject: [PATCH] ufs: Avoid M_WAITOK allocations when building a dirhash At this point the directory's vnode lock is held, so blocking while waiting for free pages makes the system more susceptible to deadlock in low memory conditions. This is particularly problematic on NUMA systems as UMA currently implements a strict first-touch policy. ufsdirhash_build() already uses M_NOWAIT for other allocations and already handled failures for the block array allocation, so just convert to M_NOWAIT. PR: 253992 Reviewed by: markj, mckusick, vangyzen (cherry picked from commit f17a5900850b4d449a91cbe9c61dfb62373c3cd1) --- sys/ufs/ufs/ufs_dirhash.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/sys/ufs/ufs/ufs_dirhash.c b/sys/ufs/ufs/ufs_dirhash.c index 13094b5a1c9..d1e1bed0bde 100644 --- a/sys/ufs/ufs/ufs_dirhash.c +++ b/sys/ufs/ufs/ufs_dirhash.c @@ -108,7 +108,7 @@ static uma_zone_t ufsdirhash_zone; #define DIRHASHLIST_LOCK() mtx_lock(&ufsdirhash_mtx) #define DIRHASHLIST_UNLOCK() mtx_unlock(&ufsdirhash_mtx) -#define DIRHASH_BLKALLOC_WAITOK() uma_zalloc(ufsdirhash_zone, M_WAITOK) +#define DIRHASH_BLKALLOC() uma_zalloc(ufsdirhash_zone, M_NOWAIT) #define DIRHASH_BLKFREE(ptr) uma_zfree(ufsdirhash_zone, (ptr)) #define DIRHASH_ASSERT_LOCKED(dh) \ sx_assert(&(dh)->dh_lock, SA_LOCKED) @@ -425,7 +425,7 @@ ufsdirhash_build(struct inode *ip) if (dh->dh_blkfree == NULL) goto fail; for (i = 0; i < narrays; i++) { - if ((dh->dh_hash[i] = DIRHASH_BLKALLOC_WAITOK()) == NULL) + if ((dh->dh_hash[i] = DIRHASH_BLKALLOC()) == NULL) goto fail; for (j = 0; j < DH_NBLKOFF; j++) dh->dh_hash[i][j] = DIRHASH_EMPTY;