From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752739AbbKXHIX (ORCPT ); Tue, 24 Nov 2015 02:08:23 -0500 Received: from mail-pa0-f49.google.com ([209.85.220.49]:33956 "EHLO mail-pa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751790AbbKXHIW (ORCPT ); Tue, 24 Nov 2015 02:08:22 -0500 Date: Tue, 24 Nov 2015 16:08:14 +0900 From: Minchan Kim To: Sergey Senozhatsky Cc: Andrew Morton , linux-kernel@vger.kernel.org, Kyeongdon Kim , Sergey Senozhatsky Subject: Re: [PATCH 2/3] zram: try vmalloc() after kmalloc() Message-ID: <20151124070814.GC7708@blaptop> References: <1448337696-10689-1-git-send-email-minchan@kernel.org> <20151124061258.GJ705@swordfish> <20151124064249.GK705@swordfish> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151124064249.GK705@swordfish> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 24, 2015 at 03:42:49PM +0900, Sergey Senozhatsky wrote: > On (11/24/15 15:12), Sergey Senozhatsky wrote: > > [..] > > > static void *zcomp_lz4_create(void) > > > { > > > - return kzalloc(LZ4_MEM_COMPRESS, GFP_KERNEL); > > > + void *ret; > > > + > > > + /* > > > + * This function could be called in swapout/fs write path > > > + * so we couldn't use GFP_FS|IO. And it assumes we already > > > + * have at least one stream in zram initialization so we > > > + * don't do best effort to allocate more stream in here. > > > + * A default stream will work well without further multiple > > > + * stream. That's why we use __GFP_NORETRY|NOWARN|NOMEMALLOC. > > > + */ > > > + ret = kzalloc(LZ4_MEM_COMPRESS, > > > + __GFP_NORETRY|__GFP_NOWARN|__GFP_NOMEMALLOC); > > > + if (!ret) > > > + ret = __vmalloc(LZ4_MEM_COMPRESS, > > > + __GFP_NORETRY|__GFP_NOWARN| > > > + __GFP_NOMEMALLOC|__GFP_ZERO, > > > + PAGE_KERNEL); > > > + return ret; > > > } > > [..] > > > > so this change is still questionable. is there a real value in having > > a vmalloc() fallback in the middle of allocations sequence: > > > > zstrm = kmalloc(sizeof(*zstrm), GFP_NOIO); > > ^^^ ok, can fail here > > > > oh, and by the way, we still can get a warning from this guy. so NOWARN in > ->create() only is not enough, should be propogated to zstrm alloc too. > so is __get_free_pages() (that was not in the original patch). > > so pass nowarn everywhere. > > perhaps something like (__GFP_NORETRY... hm...): Yep. zcomp_strm_alloc has several allocation side and they have used different flags so in our discussion, there are a few time mistakes to miss so I want to pass gfp_t from client to zcomp_strm_alloc and all of allocation sites in zcomp_strm_alloc use the flag consistenly like my [3/3]. Thanks. > > --- > > drivers/block/zram/zcomp.c | 6 ++++-- > drivers/block/zram/zcomp_lz4.c | 3 ++- > drivers/block/zram/zcomp_lzo.c | 3 ++- > 3 files changed, 8 insertions(+), 4 deletions(-) > > diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c > index c536177..c0d02d5 100644 > --- a/drivers/block/zram/zcomp.c > +++ b/drivers/block/zram/zcomp.c > @@ -76,7 +76,8 @@ static void zcomp_strm_free(struct zcomp *comp, struct zcomp_strm *zstrm) > */ > static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp) > { > - struct zcomp_strm *zstrm = kmalloc(sizeof(*zstrm), GFP_NOIO); > + struct zcomp_strm *zstrm = kmalloc(sizeof(*zstrm), GFP_NOIO | > + __GFP_NORETRY | __GFP_NOWARN | __GFP_NOMEMALLOC); > if (!zstrm) > return NULL; > > @@ -85,7 +86,8 @@ static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp) > * allocate 2 pages. 1 for compressed data, plus 1 extra for the > * case when compressed size is larger than the original one > */ > - zstrm->buffer = (void *)__get_free_pages(GFP_NOIO | __GFP_ZERO, 1); > + zstrm->buffer = (void *)__get_free_pages(GFP_NOIO | __GFP_NOWARN | > + __GFP_ZERO, 1); > if (!zstrm->private || !zstrm->buffer) { > zcomp_strm_free(comp, zstrm); > zstrm = NULL; > diff --git a/drivers/block/zram/zcomp_lz4.c b/drivers/block/zram/zcomp_lz4.c > index ee44b51..dbeee93 100644 > --- a/drivers/block/zram/zcomp_lz4.c > +++ b/drivers/block/zram/zcomp_lz4.c > @@ -15,7 +15,8 @@ > > static void *zcomp_lz4_create(void) > { > - return kzalloc(LZ4_MEM_COMPRESS, GFP_NOIO); > + return kzalloc(LZ4_MEM_COMPRESS, GFP_NOIO | __GFP_NORETRY | > + __GFP_NOWARN | __GFP_NOMEMALLOC); > } > > static void zcomp_lz4_destroy(void *private) > diff --git a/drivers/block/zram/zcomp_lzo.c b/drivers/block/zram/zcomp_lzo.c > index 683ce04..19c0857 100644 > --- a/drivers/block/zram/zcomp_lzo.c > +++ b/drivers/block/zram/zcomp_lzo.c > @@ -15,7 +15,8 @@ > > static void *lzo_create(void) > { > - return kzalloc(LZO1X_MEM_COMPRESS, GFP_NOIO); > + return kzalloc(LZO1X_MEM_COMPRESS, GFP_NOIO | __GFP_NORETRY | > + __GFP_NOWARN | __GFP_NOMEMALLOC); > } > > static void lzo_destroy(void *private) -- Kind regards, Minchan Kim