Date: Fri, 11 Sep 2015 12:58:42 +0000 (UTC) From: Andriy Gapon <avg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r287665 - stable/10/sys/cddl/contrib/opensolaris/uts/common/fs/zfs Message-ID: <201509111258.t8BCwgw5038520@repo.freebsd.org>
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Author: avg Date: Fri Sep 11 12:58:41 2015 New Revision: 287665 URL: https://svnweb.freebsd.org/changeset/base/287665 Log: MFC r287099: account for ashift when gathering buffers to be written to l2arc device The change differs from that in head because of other changes that have not been MFC-ed yet. Modified: stable/10/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c Directory Properties: stable/10/ (props changed) Modified: stable/10/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c ============================================================================== --- stable/10/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c Fri Sep 11 12:50:52 2015 (r287664) +++ stable/10/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c Fri Sep 11 12:58:41 2015 (r287665) @@ -5062,8 +5062,7 @@ l2arc_write_buffers(spa_t *spa, l2arc_de { arc_buf_hdr_t *hdr, *hdr_prev, *head; list_t *list; - uint64_t write_asize, write_psize, write_sz, headroom, - buf_compress_minsz; + uint64_t write_asize, write_sz, headroom, buf_compress_minsz; void *buf_data; kmutex_t *list_lock; boolean_t full; @@ -5079,7 +5078,7 @@ l2arc_write_buffers(spa_t *spa, l2arc_de *headroom_boost = B_FALSE; pio = NULL; - write_sz = write_asize = write_psize = 0; + write_sz = write_asize = 0; full = B_FALSE; head = kmem_cache_alloc(hdr_cache, KM_PUSHPAGE); head->b_flags |= ARC_FLAG_L2_WRITE_HEAD; @@ -5122,6 +5121,7 @@ l2arc_write_buffers(spa_t *spa, l2arc_de l2arc_buf_hdr_t *l2hdr; kmutex_t *hash_lock; uint64_t buf_sz; + uint64_t buf_a_sz; if (arc_warm == B_FALSE) hdr_prev = list_next(list, hdr); @@ -5153,7 +5153,15 @@ l2arc_write_buffers(spa_t *spa, l2arc_de continue; } - if ((write_sz + hdr->b_size) > target_sz) { + /* + * Assume that the buffer is not going to be compressed + * and could take more space on disk because of a larger + * disk block size. + */ + buf_sz = hdr->b_size; + buf_a_sz = vdev_psize_to_asize(dev->l2ad_vdev, buf_sz); + + if ((write_asize + buf_a_sz) > target_sz) { full = B_TRUE; mutex_exit(hash_lock); ARCSTAT_BUMP(arcstat_l2_write_full); @@ -5196,7 +5204,6 @@ l2arc_write_buffers(spa_t *spa, l2arc_de l2hdr->b_asize = hdr->b_size; l2hdr->b_tmp_cdata = hdr->b_buf->b_data; - buf_sz = hdr->b_size; hdr->b_l2hdr = l2hdr; list_insert_head(dev->l2ad_buflist, hdr); @@ -5211,6 +5218,7 @@ l2arc_write_buffers(spa_t *spa, l2arc_de mutex_exit(hash_lock); write_sz += buf_sz; + write_asize += buf_a_sz; } mutex_exit(list_lock); @@ -5228,6 +5236,19 @@ l2arc_write_buffers(spa_t *spa, l2arc_de } /* + * Note that elsewhere in this file arcstat_l2_asize + * and the used space on l2ad_vdev are updated using b_asize, + * which is not necessarily rounded up to the device block size. + * Too keep accounting consistent we do the same here as well: + * stats_size accumulates the sum of b_asize of the written buffers, + * while write_asize accumulates the sum of b_asize rounded up + * to the device block size. + * The latter sum is used only to validate the corectness of the code. + */ + uint64_t stats_size = 0; + write_asize = 0; + + /* * Now start writing the buffers. We're starting at the write head * and work backwards, retracing the course of the buffer selector * loop above. @@ -5275,7 +5296,7 @@ l2arc_write_buffers(spa_t *spa, l2arc_de /* Compression may have squashed the buffer to zero length. */ if (buf_sz != 0) { - uint64_t buf_p_sz; + uint64_t buf_a_sz; wzio = zio_write_phys(pio, dev->l2ad_vdev, dev->l2ad_hand, buf_sz, buf_data, ZIO_CHECKSUM_OFF, @@ -5286,13 +5307,13 @@ l2arc_write_buffers(spa_t *spa, l2arc_de zio_t *, wzio); (void) zio_nowait(wzio); - write_asize += buf_sz; + stats_size += buf_sz; /* * Keep the clock hand suitably device-aligned. */ - buf_p_sz = vdev_psize_to_asize(dev->l2ad_vdev, buf_sz); - write_psize += buf_p_sz; - dev->l2ad_hand += buf_p_sz; + buf_a_sz = vdev_psize_to_asize(dev->l2ad_vdev, buf_sz); + write_asize += buf_a_sz; + dev->l2ad_hand += buf_a_sz; } } @@ -5302,8 +5323,8 @@ l2arc_write_buffers(spa_t *spa, l2arc_de ARCSTAT_BUMP(arcstat_l2_writes_sent); ARCSTAT_INCR(arcstat_l2_write_bytes, write_asize); ARCSTAT_INCR(arcstat_l2_size, write_sz); - ARCSTAT_INCR(arcstat_l2_asize, write_asize); - vdev_space_update(dev->l2ad_vdev, write_psize, 0, 0); + ARCSTAT_INCR(arcstat_l2_asize, stats_size); + vdev_space_update(dev->l2ad_vdev, stats_size, 0, 0); /* * Bump device hand to the device start if it is approaching the end.
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