From patchwork Sun Mar 17 16:30:57 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Darrick J. Wong" X-Patchwork-Id: 13594633 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 51C931B949; Sun, 17 Mar 2024 16:30:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710693058; cv=none; b=Bl0RuwfLrK/YSf9laVbjIpeQ+6f7LJNrbsbJS9N+bszKCfvnQ45klq0I30vdAly9vs7gC2eX+A+B06IEM8ZLnmIetPwA2XhzSHbdhqM5k+8bCIcnTN61pV2HS9JLBlL5C/aVKWaj0NbRPH7/n+3wxjM+5rqOkvFLaIzD1MOfZ7I= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710693058; c=relaxed/simple; bh=JWJ6asaa3IgK2Lg0qfpCMVmw2WfKIpy4CzWRor5gTcw=; h=Date:Subject:From:To:Cc:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=GxxdVIRdTH4x7uCMKqn/RX5f7R3lNczZzrwu4NscfpoisRnes9xfpH00CSPYO5Xtxnc95kL+pIRhxDCmLM2poOlU2afPomY2MPOpHro1+01PkTi8SXW9frXI/tOBGShG75rWF2FXlecvgruSet6nFCNnxvFvj+qTVpLvqti5pws= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Xc66V4Gp; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Xc66V4Gp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2A6FBC433C7; Sun, 17 Mar 2024 16:30:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1710693058; bh=JWJ6asaa3IgK2Lg0qfpCMVmw2WfKIpy4CzWRor5gTcw=; h=Date:Subject:From:To:Cc:In-Reply-To:References:From; b=Xc66V4Gp9ro7OPX71mlUyGezytQejc0bHpiUQRCcOh7f0ZrGxpa582hNfFdh1sxn1 d4hyts6xsG4NNLr1fVKQnICAsnveYKDR3MxJRMGdmdXmY1wQGRMmnMh5Iq325b8eNj Fz/Mfw/674EEZA1mb3Ly+0JeF3skPeRChYGaQlIDDD4ai+2DHAWn7iXWbIIIdlcL3J PjwvxIPKxRFBolAHN0pbrypzXHOjrtsZ5dpS3Csj2NoUaE5eVv16rWL3+aiFNPGVSY zGBeFg1+103cyPTCDH6z4mYIEGUOgBAk6b05FG9qmMvckCXEHrDhQE1S15MX0Sd34U nylOMiQbSSshA== Date: Sun, 17 Mar 2024 09:30:57 -0700 Subject: [PATCH 29/40] xfs: shrink verity blob cache From: "Darrick J. Wong" To: djwong@kernel.org, ebiggers@kernel.org, aalbersh@redhat.com Cc: linux-fsdevel@vger.kernel.org, fsverity@lists.linux.dev, linux-xfs@vger.kernel.org Message-ID: <171069246376.2684506.9738125055810923344.stgit@frogsfrogsfrogs> In-Reply-To: <171069245829.2684506.10682056181611490828.stgit@frogsfrogsfrogs> References: <171069245829.2684506.10682056181611490828.stgit@frogsfrogsfrogs> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: fsverity@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Darrick J. Wong Add some shrinkers so that reclaim can free cached merkle tree blocks when memory is tight. We add a shrinkref variable to bias reclaim against freeing the upper levels of the merkle tree in the hope of maintaining read performance. Signed-off-by: Darrick J. Wong --- fs/xfs/xfs_trace.h | 1 + fs/xfs/xfs_verity.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 88 insertions(+) diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h index 91a73399114e..37ea6822cca3 100644 --- a/fs/xfs/xfs_trace.h +++ b/fs/xfs/xfs_trace.h @@ -4797,6 +4797,7 @@ DEFINE_EVENT(xfs_verity_cache_class, name, \ DEFINE_XFS_VERITY_CACHE_EVENT(xfs_verity_cache_load); DEFINE_XFS_VERITY_CACHE_EVENT(xfs_verity_cache_store); DEFINE_XFS_VERITY_CACHE_EVENT(xfs_verity_cache_drop); +DEFINE_XFS_VERITY_CACHE_EVENT(xfs_verity_cache_reclaim); TRACE_EVENT(xfs_verity_shrinker_count, TP_PROTO(struct xfs_mount *mp, unsigned long long count, diff --git a/fs/xfs/xfs_verity.c b/fs/xfs/xfs_verity.c index 8d1888353515..c19fa47d1f76 100644 --- a/fs/xfs/xfs_verity.c +++ b/fs/xfs/xfs_verity.c @@ -42,6 +42,9 @@ struct xfs_merkle_blob { /* refcount of this item; the cache holds its own ref */ refcount_t refcount; + /* number of times the shrinker should ignore this item */ + atomic_t shrinkref; + unsigned long flags; /* Pointer to the merkle tree block, which is power-of-2 sized */ @@ -72,6 +75,7 @@ xfs_merkle_blob_alloc( /* Caller owns this refcount. */ refcount_set(&mk->refcount, 1); + atomic_set(&mk->shrinkref, 0); mk->flags = 0; return mk; } @@ -104,8 +108,10 @@ xfs_verity_cache_drop( struct xfs_inode *ip) { XA_STATE(xas, &ip->i_merkle_blocks, 0); + struct xfs_mount *mp = ip->i_mount; struct xfs_merkle_blob *mk; unsigned long flags; + s64 freed = 0; xas_lock_irqsave(&xas, flags); xas_for_each(&xas, mk, ULONG_MAX) { @@ -113,10 +119,13 @@ xfs_verity_cache_drop( trace_xfs_verity_cache_drop(ip, xas.xa_index, _RET_IP_); + freed++; xas_store(&xas, NULL); xfs_merkle_blob_rele(mk); } + percpu_counter_sub(&mp->m_verity_blocks, freed); xas_unlock_irqrestore(&xas, flags); + xfs_inode_clear_verity_tag(ip); } /* Destroy the merkle tree block cache */ @@ -175,6 +184,7 @@ xfs_verity_cache_store( unsigned long key, struct xfs_merkle_blob *mk) { + struct xfs_mount *mp = ip->i_mount; struct xfs_merkle_blob *old; unsigned long flags; @@ -189,6 +199,8 @@ xfs_verity_cache_store( old = __xa_cmpxchg(&ip->i_merkle_blocks, key, NULL, mk, GFP_KERNEL); } while (old && !refcount_inc_not_zero(&old->refcount)); + if (!old) + percpu_counter_add(&mp->m_verity_blocks, 1); xa_unlock_irqrestore(&ip->i_merkle_blocks, flags); if (old == NULL) { @@ -234,12 +246,73 @@ struct xfs_verity_scan { unsigned long freed; }; +/* Reclaim inactive merkle tree blocks that have run out of second chances. */ +static void +xfs_verity_cache_reclaim( + struct xfs_inode *ip, + struct xfs_verity_scan *vs) +{ + XA_STATE(xas, &ip->i_merkle_blocks, 0); + struct xfs_mount *mp = ip->i_mount; + struct xfs_merkle_blob *mk; + unsigned long flags; + s64 freed = 0; + + xas_lock_irqsave(&xas, flags); + xas_for_each(&xas, mk, ULONG_MAX) { + /* + * Tell the shrinker that we scanned this merkle tree block, + * even if we don't remove it. + */ + vs->scanned++; + if (vs->sc->nr_to_scan-- == 0) + break; + + /* Retain if there are active references */ + if (refcount_read(&mk->refcount) > 1) + continue; + + /* Ignore if the item still has lru refcount */ + if (atomic_add_unless(&mk->shrinkref, -1, 0)) + continue; + + trace_xfs_verity_cache_reclaim(ip, xas.xa_index, _RET_IP_); + + freed++; + xas_store(&xas, NULL); + xfs_merkle_blob_rele(mk); + } + percpu_counter_sub(&mp->m_verity_blocks, freed); + xas_unlock_irqrestore(&xas, flags); + + /* + * Try to clear the verity tree tag if we reclaimed all the cached + * blocks. On the flag setting side, we should have IOLOCK_SHARED. + */ + xfs_ilock(ip, XFS_IOLOCK_EXCL); + if (xa_empty(&ip->i_merkle_blocks)) + xfs_inode_clear_verity_tag(ip); + xfs_iunlock(ip, XFS_IOLOCK_EXCL); + + vs->freed += freed; +} + /* Scan an inode as part of a verity scan. */ int xfs_verity_scan_inode( struct xfs_inode *ip, struct xfs_icwalk *icw) { + struct xfs_verity_scan *vs; + + vs = container_of(icw, struct xfs_verity_scan, icw); + + if (vs->sc->nr_to_scan > 0) + xfs_verity_cache_reclaim(ip, vs); + + if (vs->sc->nr_to_scan == 0) + xfs_icwalk_verity_stop(icw); + xfs_irele(ip); return 0; } @@ -512,6 +585,13 @@ xfs_verity_read_merkle( * Free the new cache blob and continue with the existing one. */ xfs_merkle_blob_rele(new_mk); + } else { + /* + * We added this merkle tree block to the cache; tag the inode + * so that reclaim will scan this inode. The caller holds + * IOLOCK_SHARED this will not race with the shrinker. + */ + xfs_inode_set_verity_tag(ip); } out_hit: @@ -519,6 +599,13 @@ xfs_verity_read_merkle( block->context = mk; block->verified = test_bit(XFS_MERKLE_BLOB_VERIFIED_BIT, &mk->flags); + /* + * Prioritize keeping the root-adjacent levels cached if this isn't a + * streaming read. + */ + if (req->level >= 0) + atomic_set(&mk->shrinkref, req->level + 1); + return 0; out_new_mk: