From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50600) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e2WUe-0001Ep-Nh for qemu-devel@nongnu.org; Thu, 12 Oct 2017 01:57:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1e2WUd-0001tG-Rh for qemu-devel@nongnu.org; Thu, 12 Oct 2017 01:57:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35128) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1e2WUd-0001sd-Ka for qemu-devel@nongnu.org; Thu, 12 Oct 2017 01:57:15 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6DA255F2984 for ; Thu, 12 Oct 2017 05:57:14 +0000 (UTC) Date: Thu, 12 Oct 2017 13:57:09 +0800 From: Peter Xu Message-ID: <20171012055709.GF30901@pxdev.xzpeter.org> References: <20171010181542.24168-1-quintela@redhat.com> <20171010181542.24168-7-quintela@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20171010181542.24168-7-quintela@redhat.com> Subject: Re: [Qemu-devel] [PATCH 06/10] migration: Make sure that we pass the right cache size List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Juan Quintela Cc: qemu-devel@nongnu.org, dgilbert@redhat.com, lvivier@redhat.com On Tue, Oct 10, 2017 at 08:15:38PM +0200, Juan Quintela wrote: > Instead of passing silently round down the number of pages, make it an > error that the cache size is not a multiple of 2. s/multiple/power/? Would this patch break existing users? > > Signed-off-by: Juan Quintela > --- > migration/page_cache.c | 12 +++++++----- > 1 file changed, 7 insertions(+), 5 deletions(-) > > diff --git a/migration/page_cache.c b/migration/page_cache.c > index 9a9d13d6a2..96268c3aea 100644 > --- a/migration/page_cache.c > +++ b/migration/page_cache.c > @@ -58,6 +58,13 @@ PageCache *cache_init(int64_t new_size, size_t page_size, Error **errp) > return NULL; > } > > + /* round down to the nearest power of 2 */ > + if (!is_power_of_2(num_pages)) { > + error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "cache size", > + "is not a power of two number of pages"); > + return NULL; > + } > + > /* We prefer not to abort if there is no memory */ > cache = g_try_malloc(sizeof(*cache)); > if (!cache) { > @@ -65,11 +72,6 @@ PageCache *cache_init(int64_t new_size, size_t page_size, Error **errp) > "Failed to allocate cache"); > return NULL; > } > - /* round down to the nearest power of 2 */ > - if (!is_power_of_2(num_pages)) { > - num_pages = pow2floor(num_pages); > - DPRINTF("rounding down to %" PRId64 "\n", num_pages); > - } > cache->page_size = page_size; > cache->num_items = 0; > cache->max_num_items = num_pages; > -- > 2.13.6 > -- Peter Xu