From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Simmons Date: Thu, 27 Feb 2020 16:11:23 -0500 Subject: [lustre-devel] [PATCH 215/622] lustre: osc: reduce atomic ops in osc_enter_cache_try In-Reply-To: <1582838290-17243-1-git-send-email-jsimmons@infradead.org> References: <1582838290-17243-1-git-send-email-jsimmons@infradead.org> Message-ID: <1582838290-17243-216-git-send-email-jsimmons@infradead.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lustre-devel@lists.lustre.org From: Li Dongyang We can reduce the number of atomic ops performed on obd_dirty_pages for the common case. WC-bug-id: https://jira.whamcloud.com/browse/LU-11775 Lustre-commit: 8b364fbd6bd9 ("LU-11775 osc: reduce atomic ops in osc_enter_cache_try") Signed-off-by: Li Dongyang Reviewed-on: https://review.whamcloud.com/33859 Reviewed-by: Patrick Farrell Reviewed-by: Alexey Lyashkov Reviewed-by: Oleg Drokin Signed-off-by: James Simmons --- fs/lustre/osc/osc_cache.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/fs/lustre/osc/osc_cache.c b/fs/lustre/osc/osc_cache.c index a18e791..bdaf65f 100644 --- a/fs/lustre/osc/osc_cache.c +++ b/fs/lustre/osc/osc_cache.c @@ -1423,7 +1423,6 @@ static void osc_consume_write_grant(struct client_obd *cli, { assert_spin_locked(&cli->cl_loi_list_lock); LASSERT(!(pga->flag & OBD_BRW_FROM_GRANT)); - atomic_long_inc(&obd_dirty_pages); cli->cl_dirty_pages++; pga->flag |= OBD_BRW_FROM_GRANT; CDEBUG(D_CACHE, "using %lu grant credits for brw %p page %p\n", @@ -1560,13 +1559,18 @@ static bool osc_enter_cache_try(struct client_obd *cli, if (osc_reserve_grant(cli, bytes) < 0) return rc; - if (cli->cl_dirty_pages < cli->cl_dirty_max_pages && - atomic_long_read(&obd_dirty_pages) + 1 <= obd_max_dirty_pages) { - osc_consume_write_grant(cli, &oap->oap_brw_page); - rc = true; - } else { - __osc_unreserve_grant(cli, bytes, bytes); + if (cli->cl_dirty_pages < cli->cl_dirty_max_pages) { + if (atomic_long_add_return(1, &obd_dirty_pages) <= + obd_max_dirty_pages) { + osc_consume_write_grant(cli, &oap->oap_brw_page); + rc = true; + goto out; + } else + atomic_long_dec(&obd_dirty_pages); } + __osc_unreserve_grant(cli, bytes, bytes); + +out: return rc; } -- 1.8.3.1