From: Christoph Hellwig <hch@infradead.org>
To: NeilBrown <neilb@suse.de>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>,
Anna Schumaker <anna.schumaker@netapp.com>,
Chuck Lever <chuck.lever@oracle.com>,
Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mgorman@suse.de>,
Christoph Hellwig <hch@infradead.org>,
David Howells <dhowells@redhat.com>,
linux-nfs@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 05/18] MM: reclaim mustn't enter FS for SWP_FS_OPS swap-space
Date: Tue, 21 Dec 2021 00:43:18 -0800 [thread overview]
Message-ID: <YcGTpjkJwhTZyUOE@infradead.org> (raw)
In-Reply-To: <163969850295.20885.4255989535187500085.stgit@noble.brown>
On Fri, Dec 17, 2021 at 10:48:22AM +1100, NeilBrown wrote:
> +static bool test_may_enter_fs(struct page *page, gfp_t gfp_mask)
> +{
> + if (gfp_mask & __GFP_FS)
> + return true;
> + if (!PageSwapCache(page) || !(gfp_mask & __GFP_IO))
> + return false;
> + /* We can "enter_fs" for swap-cache with only __GFP_IO
> + * providing this isn't SWP_FS_OPS.
> + * ->flags can be updated non-atomicially (scan_swap_map_slots),
> + * but that will never affect SWP_FS_OPS, so the data_race
> + * is safe.
> + */
> + return !data_race(page_swap_info(page)->flags & SWP_FS_OPS);
Nit: the normal kernel comment style uses an empty
/*
line to start the comment.
> @@ -1514,8 +1529,7 @@ static unsigned int shrink_page_list(struct list_head *page_list,
> if (!sc->may_unmap && page_mapped(page))
> goto keep_locked;
>
> - may_enter_fs = (sc->gfp_mask & __GFP_FS) ||
> - (PageSwapCache(page) && (sc->gfp_mask & __GFP_IO));
> + may_enter_fs = test_may_enter_fs(page, sc->gfp_mask);
>
> /*
> * The number of dirty pages determines if a node is marked
> @@ -1683,7 +1697,8 @@ static unsigned int shrink_page_list(struct list_head *page_list,
> goto activate_locked_split;
> }
>
> - may_enter_fs = true;
> + may_enter_fs = test_may_enter_fs(page,
> + sc->gfp_mask);
Now that may_enter_fs is always reset using test_may_enter_fs, do we
even need the local variable?
next prev parent reply other threads:[~2021-12-21 8:43 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-16 23:48 [PATCH 00/18 V2] Repair SWAP-over-NFS NeilBrown
2021-12-16 23:48 ` [PATCH 04/18] MM: perform async writes to SWP_FS_OPS swap-space NeilBrown
2021-12-21 8:41 ` Christoph Hellwig
2021-12-16 23:48 ` [PATCH 02/18] MM: create new mm/swap.h header file NeilBrown
2021-12-17 10:03 ` kernel test robot
2021-12-21 8:36 ` Christoph Hellwig
2021-12-16 23:48 ` [PATCH 03/18] MM: use ->swap_rw for reads from SWP_FS_OPS swap-space NeilBrown
2021-12-20 12:16 ` Mark Hemment
2021-12-21 8:40 ` Christoph Hellwig
2021-12-16 23:48 ` [PATCH 05/18] MM: reclaim mustn't enter FS for " NeilBrown
2021-12-17 8:51 ` kernel test robot
2021-12-21 8:43 ` Christoph Hellwig [this message]
2021-12-16 23:48 ` [PATCH 01/18] Structural cleanup for filesystem-based swap NeilBrown
2021-12-17 10:33 ` kernel test robot
2021-12-21 8:34 ` Christoph Hellwig
2021-12-16 23:48 ` [PATCH 06/18] MM: submit multipage reads for SWP_FS_OPS swap-space NeilBrown
2021-12-17 7:09 ` kernel test robot
2021-12-21 8:44 ` Christoph Hellwig
2021-12-16 23:48 ` [PATCH 12/18] SUNRPC/auth: async tasks mustn't block waiting for memory NeilBrown
2021-12-16 23:48 ` [PATCH 18/18] NFS: swap-out must always use STABLE writes NeilBrown
2021-12-16 23:48 ` [PATCH 10/18] NFS: swap IO handling is slightly different for O_DIRECT IO NeilBrown
2021-12-20 15:02 ` Mark Hemment
2021-12-16 23:48 ` [PATCH 15/18] NFS: discard NFS_RPC_SWAPFLAGS and RPC_TASK_ROOTCREDS NeilBrown
2021-12-16 23:48 ` [PATCH 11/18] SUNRPC/call_alloc: async tasks mustn't block waiting for memory NeilBrown
2021-12-16 23:48 ` [PATCH 08/18] MM: Add AS_CAN_DIO mapping flag NeilBrown
2021-12-19 13:38 ` Mark Hemment
2021-12-19 20:59 ` NeilBrown
2021-12-21 8:46 ` Christoph Hellwig
2022-01-19 3:54 ` NeilBrown
2021-12-16 23:48 ` [PATCH 14/18] SUNRPC: remove scheduling boost for "SWAPPER" tasks NeilBrown
2021-12-16 23:48 ` [PATCH 07/18] MM: submit multipage write for SWP_FS_OPS swap-space NeilBrown
2021-12-20 12:21 ` Mark Hemment
2021-12-16 23:48 ` [PATCH 13/18] SUNRPC/xprt: async tasks mustn't block waiting for memory NeilBrown
2021-12-16 23:48 ` [PATCH 17/18] NFSv4: keep state manager thread active if swap is enabled NeilBrown
2021-12-16 23:48 ` [PATCH 16/18] SUNRPC: improve 'swap' handling: scheduling and PF_MEMALLOC NeilBrown
2021-12-16 23:48 ` [PATCH 09/18] NFS: rename nfs_direct_IO and use as ->swap_rw NeilBrown
2021-12-17 21:29 ` [PATCH 00/18 V2] Repair SWAP-over-NFS Anna Schumaker
2021-12-19 21:07 ` NeilBrown
2021-12-21 8:48 ` Christoph Hellwig
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