A-Team_Digital_Solutions/android_kernel_motorola_sm6375
Watch
2
0
Fork
You've already forked android_kernel_motorola_sm6375
 0
mirror of https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git synced 2026-10-28 10:41:38 -04:00
Code Issues Projects Releases Packages Wiki Activity

[PATCH] fdtable: Make fdarray and fdsets equal in size

Browse source 
Currently, each fdtable supports three dynamically-sized arrays of data: the
fdarray and two fdsets.  The code allows the number of fds supported by the
fdarray (fdtable->max_fds) to differ from the number of fds supported by each
of the fdsets (fdtable->max_fdset).

In practice, it is wasteful for these two sizes to differ: whenever we hit a
limit on the smaller-capacity structure, we will reallocate the entire fdtable
and all the dynamic arrays within it, so any delta in the memory used by the
larger-capacity structure will never be touched at all.

Rather than hogging this excess, we shouldn't even allocate it in the first
place, and keep the capacities of the fdarray and the fdsets equal.  This
patch removes fdtable->max_fdset.  As an added bonus, most of the supporting
code becomes simpler.

Signed-off-by: Vadim Lobanov <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Dipankar Sarma <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Vadim Lobanov 2006-12-10 02:21:12 -08:00 • committed by Linus Torvalds
commit bbea9f6966
13 changed files with 48 additions and 81 deletions
Download patch file Download diff file Expand all files Collapse all files

56
fs/file.c
View file

@ -68,8 +68,8 @@ void free_fd_array(struct file **array, int num)
static void __free_fdtable(struct fdtable *fdt)
{
free_fdset(fdt->open_fds, fdt->max_fdset);
free_fdset(fdt->close_on_exec, fdt->max_fdset);
free_fdset(fdt->open_fds, fdt->max_fds);
free_fdset(fdt->close_on_exec, fdt->max_fds);
free_fd_array(fdt->fd, fdt->max_fds);
kfree(fdt);
}
@ -98,7 +98,7 @@ static void free_fdtable_rcu(struct rcu_head *rcu)
struct fdtable_defer *fddef;
BUG_ON(!fdt);
fdset_size = fdt->max_fdset / 8;
fdset_size = fdt->max_fds / 8;
fdarray_size = fdt->max_fds * sizeof(struct file *);
if (fdt->free_files) {
@ -110,13 +110,11 @@ static void free_fdtable_rcu(struct rcu_head *rcu)
kmem_cache_free(files_cachep, fdt->free_files);
return;
}
if (fdt->max_fdset <= EMBEDDED_FD_SET_SIZE &&
fdt->max_fds <= NR_OPEN_DEFAULT) {
if (fdt->max_fds <= NR_OPEN_DEFAULT)
/*
* The fdtable was embedded
*/
return;
}
if (fdset_size <= PAGE_SIZE && fdarray_size <= PAGE_SIZE) {
kfree(fdt->open_fds);
kfree(fdt->close_on_exec);
@ -136,9 +134,7 @@ static void free_fdtable_rcu(struct rcu_head *rcu)
void free_fdtable(struct fdtable *fdt)
{
if (fdt->free_files ||
fdt->max_fdset > EMBEDDED_FD_SET_SIZE ||
fdt->max_fds > NR_OPEN_DEFAULT)
if (fdt->free_files || fdt->max_fds > NR_OPEN_DEFAULT)
call_rcu(&fdt->rcu, free_fdtable_rcu);
}
@ -151,12 +147,11 @@ static void copy_fdtable(struct fdtable *nfdt, struct fdtable *fdt)
int i;
int count;
BUG_ON(nfdt->max_fdset < fdt->max_fdset);
BUG_ON(nfdt->max_fds < fdt->max_fds);
/* Copy the existing tables and install the new pointers */
i = fdt->max_fdset / (sizeof(unsigned long) * 8);
count = (nfdt->max_fdset - fdt->max_fdset) / 8;
i = fdt->max_fds / (sizeof(unsigned long) * 8);
count = (nfdt->max_fds - fdt->max_fds) / 8;
/*
* Don't copy the entire array if the current fdset is
@ -164,9 +159,9 @@ static void copy_fdtable(struct fdtable *nfdt, struct fdtable *fdt)
*/
if (i) {
memcpy (nfdt->open_fds, fdt->open_fds,
fdt->max_fdset/8);
fdt->max_fds/8);
memcpy (nfdt->close_on_exec, fdt->close_on_exec,
fdt->max_fdset/8);
fdt->max_fds/8);
memset (&nfdt->open_fds->fds_bits[i], 0, count);
memset (&nfdt->close_on_exec->fds_bits[i], 0, count);
}
@ -201,7 +196,7 @@ fd_set * alloc_fdset(int num)
void free_fdset(fd_set *array, int num)
{
if (num <= EMBEDDED_FD_SET_SIZE) /* Don't free an embedded fdset */
if (num <= NR_OPEN_DEFAULT) /* Don't free an embedded fdset */
return;
else if (num <= 8 * PAGE_SIZE)
kfree(array);
@ -220,18 +215,6 @@ static struct fdtable *alloc_fdtable(int nr)
if (!fdt)
goto out;
nfds = max_t(int, 8 * L1_CACHE_BYTES, roundup_pow_of_two(nr + 1));
if (nfds > NR_OPEN)
nfds = NR_OPEN;
new_openset = alloc_fdset(nfds);
new_execset = alloc_fdset(nfds);
if (!new_openset || !new_execset)
goto out;
fdt->open_fds = new_openset;
fdt->close_on_exec = new_execset;
fdt->max_fdset = nfds;
nfds = NR_OPEN_DEFAULT;
/*
* Expand to the max in easy steps, and keep expanding it until
@ -251,15 +234,21 @@ static struct fdtable *alloc_fdtable(int nr)
nfds = NR_OPEN;
}
} while (nfds <= nr);
new_openset = alloc_fdset(nfds);
new_execset = alloc_fdset(nfds);
if (!new_openset || !new_execset)
goto out;
fdt->open_fds = new_openset;
fdt->close_on_exec = new_execset;
new_fds = alloc_fd_array(nfds);
if (!new_fds)
goto out2;
goto out;
fdt->fd = new_fds;
fdt->max_fds = nfds;
fdt->free_files = NULL;
return fdt;
out2:
nfds = fdt->max_fdset;
out:
free_fdset(new_openset, nfds);
free_fdset(new_execset, nfds);
@ -290,7 +279,7 @@ static int expand_fdtable(struct files_struct *files, int nr)
* we dropped the lock
*/
cur_fdt = files_fdtable(files);
if (nr >= cur_fdt->max_fds || nr >= cur_fdt->max_fdset) {
if (nr >= cur_fdt->max_fds) {
/* Continue as planned */
copy_fdtable(new_fdt, cur_fdt);
rcu_assign_pointer(files->fdt, new_fdt);
@ -316,11 +305,10 @@ int expand_files(struct files_struct *files, int nr)
fdt = files_fdtable(files);
/* Do we need to expand? */
if (nr < fdt->max_fdset && nr < fdt->max_fds)
if (nr < fdt->max_fds)
return 0;
/* Can we expand? */
if (fdt->max_fdset >= NR_OPEN || fdt->max_fds >= NR_OPEN ||
nr >= NR_OPEN)
if (nr >= NR_OPEN)
return -EMFILE;
/* All good, so we try */