From patchwork Tue Apr 30 03:28:16 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: 13648076 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 6EE42156C2; Tue, 30 Apr 2024 03:28:17 +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=1714447697; cv=none; b=rFeCSn8ykVhp7kpf+gzHyQQA6+CAcPqT8KgGCmKpsyrmhvx0gDqpiU/XX0O0zS/6wxangR47xfWhbfMbTfS1NAPXxw46UeSmdTDPmhkencZ/TPH9GcVP8Vm3toG9iHw22Yl4tBIOyzJPsK+o8jkV0rkv774vY3p6JnTzVhsbRfg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714447697; c=relaxed/simple; bh=Vkmr4g33MoOF/Zqsrvn4ruSmF3/aw67gsvBQJB9Oh9s=; h=Date:Subject:From:To:Cc:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=VEfapR0IJPFP+tAVelEiBreX/ae0QEWpJEvHV3zi0Fkx7xaOL+5rLcdjy3LUqwXOvLh/RnoWaRJ9pVYreVVi7JGdORnoDsIPAdtAZda+Z3dY7rYavtAoUPCwed5UGmRNoafzvShkQOFznclJ+whuc1l+/EInfHFLxTWLEpFHmy4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ku9/CaVN; 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="Ku9/CaVN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 46B14C116B1; Tue, 30 Apr 2024 03:28:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1714447697; bh=Vkmr4g33MoOF/Zqsrvn4ruSmF3/aw67gsvBQJB9Oh9s=; h=Date:Subject:From:To:Cc:In-Reply-To:References:From; b=Ku9/CaVN0DnrJtoTv3MrlxNDVsXe44a3eDSJfX+/I2qupn//NGpO/nFdUOjQRoMHD MTHx5xgSRwdIb9YpKkgfEHWK6dNm7OSsDsWSLLanRn8dx9PPV/7m8w7XDczwYuNmWP tea76pd+srnZ0MxfdAzn7CDbe+3IlVC05+Z5nBT5iNXx6iylG4JzSEHDexdVEw/jUF IXc5BfKtUwfhs0Qp65HqJhy8+08tGsrz8SVHf309f+SjhJPL4f+eHv5M3wPl/FR1U2 cNc/XggVqFf2Ei9V8x1q9splv7ONXqyWuA0auohKon3nfxMMYRK91ci5C9ghJR8X5C 0dgAEfSvuyerw== Date: Mon, 29 Apr 2024 20:28:16 -0700 Subject: [PATCH 16/26] xfs: shrink verity blob cache From: "Darrick J. Wong" To: aalbersh@redhat.com, ebiggers@kernel.org, djwong@kernel.org Cc: linux-xfs@vger.kernel.org, alexl@redhat.com, walters@verbum.org, fsverity@lists.linux.dev, linux-fsdevel@vger.kernel.org Message-ID: <171444680638.957659.5700993395267457237.stgit@frogsfrogsfrogs> In-Reply-To: <171444680291.957659.15782417454902691461.stgit@frogsfrogsfrogs> References: <171444680291.957659.15782417454902691461.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_fsverity.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++++- fs/xfs/xfs_trace.h | 23 +++++++++++++ 2 files changed, 111 insertions(+), 1 deletion(-) diff --git a/fs/xfs/xfs_fsverity.c b/fs/xfs/xfs_fsverity.c index ae3d1bdac2876..546c7ec6daadc 100644 --- a/fs/xfs/xfs_fsverity.c +++ b/fs/xfs/xfs_fsverity.c @@ -50,6 +50,9 @@ 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 */ @@ -89,6 +92,7 @@ xfs_merkle_blob_alloc( /* Caller owns this refcount. */ refcount_set(&mk->refcount, 1); + atomic_set(&mk->shrinkref, 0); mk->flags = 0; mk->key.ino = ip->i_ino; mk->key.pos = pos; @@ -321,18 +325,94 @@ xfs_fsverity_shrinker_count( return min_t(u64, ULONG_MAX, count); } +struct xfs_fsverity_scan { + struct shrink_control *sc; + + unsigned long scanned; + unsigned long freed; +}; + +/* Reclaim inactive merkle tree blocks that have run out of second chances. */ +static void +xfs_fsverity_perag_reclaim( + struct xfs_perag *pag, + struct xfs_fsverity_scan *vs) +{ + struct rhashtable_iter iter; + struct xfs_mount *mp = pag->pag_mount; + struct xfs_merkle_blob *mk; + s64 freed = 0; + + rhashtable_walk_enter(&pag->pagi_merkle_blobs, &iter); + rhashtable_walk_start(&iter); + while ((mk = rhashtable_walk_next(&iter)) != NULL) { + if (IS_ERR(mk)) + continue; + + /* + * 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; + + /* + * Grab our own active reference to the blob handle. If we + * can't, then we're racing with a cache drop and can move on. + */ + if (!refcount_inc_not_zero(&mk->refcount)) + continue; + + rhashtable_walk_stop(&iter); + + trace_xfs_fsverity_cache_reclaim(mp, &mk->key, _RET_IP_); + + xfs_merkle_blob_drop(pag, mk); + freed++; + + rhashtable_walk_start(&iter); + } + rhashtable_walk_stop(&iter); + rhashtable_walk_exit(&iter); + + percpu_counter_sub(&mp->m_verity_blocks, freed); + vs->freed += freed; +} + /* Actually try to reclaim merkle tree blocks. */ static unsigned long xfs_fsverity_shrinker_scan( struct shrinker *shrink, struct shrink_control *sc) { + struct xfs_fsverity_scan vs = { .sc = sc }; struct xfs_mount *mp = shrink->private_data; + struct xfs_perag *pag; + xfs_agnumber_t agno; if (!xfs_has_verity(mp)) return SHRINK_STOP; - return 0; + for_each_perag(mp, agno, pag) { + xfs_fsverity_perag_reclaim(pag, &vs); + + if (sc->nr_to_scan == 0) { + xfs_perag_rele(pag); + break; + } + } + + trace_xfs_fsverity_shrinker_scan(mp, vs.scanned, vs.freed, _RET_IP_); + return vs.freed; } /* Set up fsverity for this mount. */ @@ -765,6 +845,13 @@ xfs_fsverity_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 != FSVERITY_STREAMING_READ) + atomic_set(&mk->shrinkref, req->level + 1); + return 0; out_new_mk: diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h index 3810e20b9ee9b..21e8643e021eb 100644 --- a/fs/xfs/xfs_trace.h +++ b/fs/xfs/xfs_trace.h @@ -5979,6 +5979,29 @@ TRACE_EVENT(xfs_fsverity_shrinker_count, __entry->count, __entry->caller_ip) ) + +TRACE_EVENT(xfs_fsverity_shrinker_scan, + TP_PROTO(struct xfs_mount *mp, unsigned long scanned, + unsigned long freed, unsigned long caller_ip), + TP_ARGS(mp, scanned, freed, caller_ip), + TP_STRUCT__entry( + __field(dev_t, dev) + __field(unsigned long, scanned) + __field(unsigned long, freed) + __field(void *, caller_ip) + ), + TP_fast_assign( + __entry->dev = mp->m_super->s_dev; + __entry->scanned = scanned; + __entry->freed = freed; + __entry->caller_ip = (void *)caller_ip; + ), + TP_printk("dev %d:%d scanned %lu freed %lu caller %pS", + MAJOR(__entry->dev), MINOR(__entry->dev), + __entry->scanned, + __entry->freed, + __entry->caller_ip) +) #endif /* CONFIG_XFS_VERITY */ #endif /* _TRACE_XFS_H */